BLUENRG-232 - STMICROELECTRONICS

Features

• Bluetooth Low Energy system-on-chip Bluetooth v5.2 certified, supporting:

–Master, slave and multiple simultaneous roles

– LE Privacy 1.2 and LE secure connection

– LE data packet length extension

• Operating supply voltage: from 1.7 to 3.6 V

• Integrated linear regulator and DC-DC step-down converter

• Operating temperature range: -40 °C to 105 °C

• High performance, ultra-low power Cortex-M0 32-bit based architecture core

• Programmable 256 kB Flash

• 24 kB RAM with retention (two 12 kB banks)

• 1 x UART interface

• 1 x SPI interface

• 2 x I²C interface

• 14, 15 or 26 GPIOs

• 2 x multifunction timer

• 10-bit ADC

• Watchdog and RTC

• DMA controller

• PDM stream processor

• 16 or 32 MHz crystal oscillator

• 32 kHz crystal oscillator

• 32 kHz ring oscillator

• Battery voltage and temperature sensors

• Up to +8 dBm available output power (at antenna connector)

• Excellent RF link budget (up to 96 dB)

• Accurate RSSI to allow power control

• 8.3 mA TX current (@ -2 dBm, 3.0 V)

• Down to 1 µA current consumption with active BLE stack (sleep mode)

• ST companion integrated balun/filter chips are available

• Average advertisement current consumption 15.34 µA (advertisement interval

1000 ms) – 1 year, 8 months, 19 days with 230 mAh battery (CR2032)

• Average connection current consumption 7.059 µA (connection interval 1000

ms) – 3 years, 10 months, 12 days with 230 mAh battery (CR2032)

• Suitable for building applications compliant with the following radio frequency

regulations: ETSI EN 300 328, EN 300 440, FCC CFR47 part 15, ARIB STD-

T66

• Pre-programmed bootloader via UART

• QFN32, QFN48 and WCSP34 package options

Applications

• Watches

• Fitness, wellness and sports

Product status link

BlueNRG-2

Bluetooth® Low Energy wireless system-on-chip

BlueNRG-2

DS12166 - Rev 7 - December 2020

For further information contact your local STMicroelectronics sales office.

www.st.com

• Consumer medical

•Security/proximity

•Remote control

• Home and industrial automation

• Assisted living

• Mobile phone peripherals

• Lighting

• PC peripherals

BlueNRG-2

DS12166 - Rev 7 page 2/169

1Description

The BlueNRG-2 is a very low power Bluetooth Low Energy (BLE) single-mode system-on-chip, compliant with

Bluetooth specifications.

The BlueNRG-2 extends the features of award-winning BlueNRG network processor, enabling the usage of the

embedded Cortex M0 to run the user application code.

The BlueNRG-2 includes 256 kB of programming Flash memory, 24 kB of static RAM memory with retention (two

12 kB banks) and SPI, UART, I²C standard communication interface peripherals. It also features multifunction

timers, watchdog, RTC and DMA controller.

An ADC is available to interface with analog sensors, and to read the measurement of the integrated battery

voltage sensor. A digital filter is available to process a PDM stream.

The BlueNRG-2 offers the same excellent RF performance of the BlueNRG radio, and the integrated high

efficiency DC-DC converter keeps the same ultra-low power characteristics, but the BlueNRG-2 improves the

BlueNRG sleep mode current consumption allowing a further increase in the battery lifetime of the applications.

Figure 1. BlueNRG-2 architecture

RF AFE

LDOs

Rcosc Xosc

Modulation

Demodulation

Blue

Cortex

-M0

DMA

AHB Bus matrix

3x Masters

7x Slaves

Flash Controller

12 kB SRAM Switchable

12 kB SRAM always On

AHB2APB bridge

PKA 1 kB SRAM

RNG

256 kB Flash Array

14,15 or 26x GPIOs

SPI

UART

2x I2C

2x MFT

Watchdog

RTC

CRMU

(Clock and Reset

Management Unit)

ADC IF

AUX ADC

BlueNRG-2

Description

DS12166 - Rev 7 page 3/169

Figure 2. BlueNRG-2 bus architecture

AHB-APB

Bridge

SPI

2 x I2C

UART

2 x MFT

WDG

RTC

GPIOs

CM0

FLASH

(256 KB)

RAM

(24 KB)

DMA

2.4 GHz

radio

RNG

ADC

SWD

PKA

BlueNRG-2

Description

DS12166 - Rev 7 page 4/169

2BlueNRG-2 Bluetooth Low Energy stack

The BlueNRG-2 is complemented with a Bluetooth Low Energy stack C library that provides:

• Master, slave role support

• GAP: central, peripheral, observer or broadcaster roles

• ATT/GATT: client and server

• SM: privacy, authentication and authorization

• L2CAP

• Link layer: AES-128 encryption and decryption

The BlueNRG-2 can be configured to support single chip or network processor applications.

The BlueNRG-2 supports LE data packet length extension, in compliance with Buetooth Low Energy specification.

In the first configuration, the BlueNRG-2 operates as single device in the application for managing both the

application code and the Bluetooth Low Energy stack. The whole Bluetooth low energy stack is provided as object

code in a single library file whereas the GATT low energy profiles are provided as object codes in separate

libraries.

The figure below shows the single chip RF software layers.

Figure 3. BlueNRG-2 single-chip RF software layers

The BlueNRG-2 can be configured to operate as a network coprocessor. In this case, dedicated firmware is

provided to support the interface with an external application processor. The whole Bluetooth low energy stack

runs in the BlueNRG-2; the GATT profiles are provided to run in the application processor together with the

application code. The figure below shows the network processor RF software layers.

BlueNRG-2

BlueNRG-2 Bluetooth Low Energy stack

DS12166 - Rev 7 page 5/169

Figure 4. BlueNRG-2 network processor RF software layers

BlueNRG-2

BlueNRG-2 Bluetooth Low Energy stack

DS12166 - Rev 7 page 6/169

3Functional details

The BlueNRG-2 integrates:

• ARM Cortex-M0 core

•Interrupts management

• 256 kB Flash memory

• 24 kB of RAM with two retention options (12 kB or 24 kB)

• Power management

• Clocks

• Bluetooth low energy radio

• Random number generator (RNG) (reserved for Bluetooth low energy protocol stack, but user applications

can read it)

• Public key cryptography (PKA) (reserved for Bluetooth low energy protocol stack)

• Peripherals:

– SPI interface

– UART interface

– I²C bus interface

– GPIO

– Multifunction timer

– DMA controller

– Watchdog

– RTC

– ADC with battery voltage sensor and temperature sensor

– PDM stream processor

3.1 Core

The ARM® Cortex®-M0 processor has been developed to provide a low-cost platform that meets the needs

of MCU implementation, with a reduced pin count and low-power consumption, while delivering outstanding

computational performance and an advanced system response to interrupts.

The ARM® Cortex®-M0 32-bit RISC processor features exceptional code-efficiency, delivering the high-

performance expected from an ARM core in the memory size usually associated with 8-bit and 16-bit devices.

The BlueNRG-2 has an embedded ARM core and is therefore compatible with all ARM tools and software.

3.2 Interrupts

The Cortex-M0 nested vector interrupt controller (NVIC) handles interrupts. The NVIC controls specific Cortex-M0

interrupts (address 0x00 to 0x3C) as well as 32-user interrupts (address 0x40 to 0xBC). In the BlueNRG-2 device,

the user interrupts are connected to the interrupt signals of the different peripherals.

Table 1. BlueNRG-2 interrupt vectors

Position Priority Priority type Description Address

Initial main SP 0x0000_0000

-3 Fixed Reset handler 0x0000_0004

-2 Fixed NMI handler 0x0000_0008

-1 Fixed HardFault handler 0x0000_000C

RESERVED 0x0000_000C – 0x0000_0028

3 Settable SVC handler 0x0000_002C

BlueNRG-2

Functional details

DS12166 - Rev 7 page 7/169

Position Priority Priority type Description Address

RESERVED 0x0000_0030 - 0x0000_0034

5 Settable PendSV handler 0x0000_0038

6 Settable SystemTick handler 0x0000_003C

0 Init 0 Settable GPIO interrupt 0x0000_0040

1 Init 0 Settable FLASH controller interrupt 0x0000_0044

2 Init 0 Settable RESERVED 0x0000_0048

3 Init 0 Settable RESERVED 0x0000_004C

4 Init 0 Settable UART interrupt 0x0000_0050

5 Init 0 Settable SPI interrupt 0x0000_0054

6 Init 0 CRITICAL BLE controller interrupt 0x0000_0058

7 Init 0 Settable Watchdog interrupt 0x0000_005C

8 Init 0 Settable RESERVED 0x0000_0060

9 Init 0 Settable RESERVED 0x0000_0064

10 Init 0 Settable RESERVED 0x0000_0068

11 Init 0 Settable RESERVED 0x0000_006C

12 Init 0 Settable RESERVED 0x0000_0070

13 Init 0 Settable ADC interrupt 0x0000_0074

14 Init 0 Settable I2C 2 interrupt 0x0000_0078

15 Init 0 Settable I2C 1 interrupt 0x0000_007C

16 Init 0 Settable RESERVED 0x0000_0080

17 Init 0 Settable MFT1 A interrupt 0x0000_0084

18 Init 0 Settable MFT1 B interrupt 0x0000_0088

19 Init 0 Settable MFT2 A interrupt 0x0000_008C

20 Init 0 Settable MFT2 B interrupt 0x0000_0090

21 Init 0 Settable RTC interrupt 0x0000_0094

22 Init 0 Settable PKA interrupt 0x0000_0098

23 Init 0 Settable DMA interrupt 0x0000_009C

24 – 31 Init 0 Settable RESERVED 0x0000_00A0 – 0x0000_00BC

3.3 Memories

The memory subsystem consists 256 kB Flash memory and two banks of 12 kB ultra-low leakage static RAM

blocks.

The 256 kB Flash memory is available to the user and can be accessed per 32-bit for read access and per 32-bit

for write access (with 4x32-bit FIFO).

The access to the static RAM can be bytes, half words (16 bits) or words (32 bits).

The two banks of 12 kB RAM blocks are always in retention mode.

3.4 Power management

The BlueNRG-2 integrates both a low dropout voltage regulator (LDO) and a step-down DC-DC converter to

supply the internal BlueNRG-2 circuitry.

The BlueNRG-2 most efficient power management configuration is with DC-DC converter active where best

power consumption is obtained without compromising performances. Nevertheless, a configuration based on LDO

can also be used, if needed.

BlueNRG-2

Memories

DS12166 - Rev 7 page 8/169

A simplified version of the state machine is shown below.

Figure 5. BlueNRG-2 power management state machine

3.4.1 State description

3.4.1.1 Preactive state

The preactive state is the default state after a POR event.

In this state:

•All the digital power supplies are stable.

•The high frequency clock runs on internal fast clock RC oscillator (16 MHz).

• The low frequency clock runs on internal RC oscillator (32.768 kHz).

3.4.1.2 Active state

In this state:

• The high frequency runs on the accurate clock (16 MHz ±50 ppm) provided by the external XO. The internal

fast clock RO oscillator is switched off.

3.4.1.3 Standby state

In this state:

• Only the digital power supplies necessary to keep the RAM in retention are used.

The wake-up from this low power state is driven by the following sources:

•IO9

• IO10

• IO11

• IO12

• IO13(1)

1. Not available on WCSP34.

If they have been programmed as wake-up source in the system controller registers.

3.4.1.4 Sleep state

In this state:

•Only the digital power supplies necessary to keep the RAM in retention are used.

BlueNRG-2

Power management

DS12166 - Rev 7 page 9/169

• The low frequency oscillator is switched on.

The wake-up from this low power state is driven by the following sources:

• IO9

•IO10

• IO11

• IO12

• IO13 (1)

1. Not available on WCSP34.

If they have been programmed as wake-up source in the system controller registers and from the internal timers

of the BLE radio.

3.4.1.5 GPIO management during low power modes

3.4.1.5.1 IO wake-up sources

The IOs programmed to be wake-up sources need an external drive according to the selected level sensitivity.

If the wake-up level is high level, a pull-down drive should be used. If the wake-up level is low level, a pull-up

drive should be used.

If no external drive is applied, IO9, IO10 and IO11 are only sensitive to low level as they have an internal pull-up

(activated by default). IO12 and IO13 do not have an internal pull and therefore require an external drive.

3.4.1.5.2 Wake-up time

The wake-up time is typically 200 µs at 3.0 V and a temperature of 25 °C.

3.4.1.5.3 GPIO special settings in low power modes

The GPIO9, GPIO10 and GPIO11 can be configured as output GPIO during sleep and standby mode. In addition,

they can have enabled their internal pull. Their configuration is done in specific registers:

•SLEEPIO_OEN: has the same functionality of the register OEN (GPIO peripheral) and it is used to configure

in output mode or input mode (default)

•SLEEPIO_PE: has the same functionality of the register PE (GPIO peripheral) and it is used to enable the

internal pull. This register allows the internal pull of these IOs to be enabled or disabled also if they are not

configured in output state.

• SLEEPIO_DS: has the same functionality of the register DS (GPIO peripheral) and it is used to configure the

drive strength

• SLEEPIO_OUT: has the same functionality of the register DATA (GPIO peripheral) and it is used to set the

state of the GPIO (high state or low state)

Note: If the GPIO9, GPIO10 or GPIO11 are used as wake-up source, then the SLEEPIO_OEN has no effect, but it is

always possible to enable or disable the internal pull.

3.4.2 Power saving strategy

The application power saving strategy is based on clock stopping, dynamic clock gating,

digital power supply switch off and analog current consumption minimization.

A summary of functional blocks versus the BlueNRG-2 states is provided below.

Table 2. Relationship between the BlueNRG-2 states and functional blocks

Functional blocks RESET STANDBY SLEEP Preactive Active LOCK RX/

LOCK TX RX TX

LDO_SOFT_1V2 or

LDO_SOFT_0V9 OFF ON ON ON ON ON ON ON

LDO_STRONG_1V2 OFF OFF OFF ON ON ON ON ON

BlueNRG-2

Power management

DS12166 - Rev 7 page 10/169

Functional blocks RESET STANDBY SLEEP Preactive Active LOCK RX/

LOCK TX RX TX

LDO_DIG_1V8 OFF OFF OFF ON ON ON ON ON

SMPS OFF OFF OFF ON ON ON ON ON

LDO_DIG_1V2 OFF OFF OFF ON ON ON ON ON

BOR OFF OFF OFF ON ON ON ON ON

16 MHz RO OFF OFF OFF ON OFF OFF OFF OFF

16 MHz XO OFF OFF OFF OFF ON ON ON ON

32 kHz RO or XO OFF OFF ON ON ON ON ON ON

3.4.3 System controller registers

SYSTEM_CTRL peripheral base address (SYSTEM_CTRL_BASE_ADDR) 0x40200000.

Table 3. SYSTEM_CTRL registers

Address offset Name RW Reset Description

0x00 WKP_IO_IS RW 0x00000000

Level selection for wake-up IO (1 bit for IO).

0: The system wakes up when IO is low.

1: The system wakes up when IO is high.

0x04 WKP_IO_IE RW 0x00000007

Enables the IO that wakes up the device (1 bit for

IO).

0: The wake-up feature on the IO is disabled.

1: The wake-up feature on the IO is enabled.

0x08 CTRL RW 0x00000000 XO frequency indication is provided by the

application. Refer to the detailed description below.

0x0C SLEEPIO_OEN RW 0x00000007 GPIO output enable register for low power modes.

0x10 SLEEPIO_OUT RW 0x00000000 GPIO output value register for low power modes.

0x14 SLEEPIO_DS RW 0x00000000 GPIO drive strength control register for low power

modes.

0x18 SLEEPIO_PE RW 0x00000000 GPIO pull enable register for low power modes.

Table 4. SYSTEM_CTRL - WKP_IO_IS register description: address offset SYSTEM_CTRL_BASE_ADDR+0x00

Bit Field name Reset RW Description

4:0 LEVEL_SEL 0x00 RW

Selects the active wake-up level for the five IOs.

0: The system wakes up when IO is low.

1: The system wakes up when IO is high.

One bit by IO:

Bit0: IO9

Bit1: IO10

Bit2: IO11

Bit3: IO12

Bit4: IO13

31:5 RESERVED 0x00 RW RESERVED

BlueNRG-2

Power management

DS12166 - Rev 7 page 11/169

Table 5. SYSTEM_CTRL - WKP_IO_IE register description: address offset SYSTEM_CTRL_BASE_ADDR+0x04

Bit Field name Reset RW Description

4:0 IO_WAKEUP_EN 0x07 RW

Enables the IOs to be wake-up source.

0: Wake-up on the IO disabled.

1: Wake-up on the IO enabled.

One bit by IO:

Bit0: IO9

Bit1: IO10

Bit2: IO11

Bit3: IO12

Bit4: IO13

31:5 RESERVED 0x00 RW RESERVED

Table 6. SYSTEM_CTRL - CTRL register description: address offset SYSTEM_CTRL_BASE_ADDR+0x08

Bit Field name Reset RW Description

0 MHZ32_SEL 0x0 RW

Indicates the crystal frequency used in the

application.

0: The 16 MHz is selected.

1: The 32 MHz is selected.

31:1 RESERVED 0x0 RW RESERVED

Table 7. SYSTEM_CTRL - SLEEPIO_OEN register description: address offset SYSTEM_CTRL_BASE_ADDR+0x0C

Bit Field name Reset RW Description

2:0 SLEEPIO_OEN 0x07 RW

Enables the IOs to act as output during low power

modes.

0: output mode.

1: input mode.

One bit by IO:

Bit0: IO9

Bit1: IO10

Bit2: IO11

31:4 RESERVED 0x00 RW RESERVED

Table 8. SYSTEM_CTRL – SLEEPIO_OUT register description: address offset SYSTEM_CTRL_BASE_ADDR+0x10

Bit Field name Reset RW Description

2:0 SLEEPIO_OUT 0x00 RW

Writing to a bit drives the written value on the

corresponding IO when it is configured in output

direction in SLEEPIO_OEN register. Reading a bit in

this register returns the last written value. One bit by

IO:

Bit0: IO9

Bit1: IO10

Bit2: IO11

31:4 RESERVED 0x00 RW RESERVED

BlueNRG-2

Power management

DS12166 - Rev 7 page 12/169

Table 9. SYSTEM_CTRL - SLEEPIO_DS register description: address offset SYSTEM_CTRL_BASE_ADDR+0x14

Bit Field name Reset RW Description

2:0 SLEEPIO_DS 0x00 RW

Configure the drive strength during low power modes

for the IO9, IO10 and IO11.

0: low drive strength.

1: high drive strength

One bit by IO:

Bit0: IO9

Bit1: IO10

Bit2: IO11

31:4 RESERVED 0x00 RW RESERVED

Table 10. SYSTEM_CTRL - SLEEPIO_PE register description: address offset SYSTEM_CTRL_BASE_ADDR+0x18

Bit Field name Reset RW Description

2:0 SLEEPIO_PE 0x00 RW

Enable/disable the internal pull during low power

modes for the IO9, IO10 and IO11.

0: pull disabled.

1: pull enabled.

One bit by IO:

Bit0: IO9

Bit1: IO10

Bit2: IO11

31:4 RESERVED 0x00 RW RESERVED

AHBUPCONV peripheral base address (AHBUPCONV_BASE_ADDR) 0x40C00000.

Table 11. AHBUPCONV registers

Address offset Name RW Reset Description

0x00 COMMAND RW 0x00000000 AHB up/down converter command register

BLUE_CTRL peripheral base address (BLUE_CTRL_BASE_ADDR) 0x48000000.

Table 12. BLUE_CTRL registers

Address offset Name RW Reset Description

0x04 TIMEOUT RW 0x00000000 Timeout programming register

0x0C RADIO_CONFIG RW 0x00000000 Radio configuration register

Note: All RESERVED fields inside registers must always be written with their default value.

3.5 Clocks and reset management

The BlueNRG-2 embeds an RC low-speed frequency oscillator at 32 kHz and an RO high-speed frequency

oscillator at 16 MHz.

The low-frequency clock is used in low power mode and can be supplied either by a 32.7 kHz oscillator that uses

an external crystal and guarantees up to ±50 ppm frequency tolerance, or by a ring oscillator, which does not

require any external components.

BlueNRG-2

Clocks and reset management

DS12166 - Rev 7 page 13/169

The primary high-speed frequency clock is a 16 MHz or 32 MHz crystal oscillator. A fast-starting 16 MHz ring

oscillator provides the clock while the crystal oscillator is starting up. Frequency tolerance of high-speed crystal

oscillator is ±50 ppm.

The usage of the 16 MHz (for constraints related to the 16 MHz high-speed crystal usage, refer to the BlueNRG-1

DK SW release notes) (or 32 MHz) crystal is strictly necessary for RF communications.

The clock tree for the peripherals is as follows:

Figure 6. Clock tree

CLOCK_EN->WDG

CLOCK_EN->RTC

CLOCK_EN->NVM

CLOCK_EN->ADC

CLOCK_EN->I2Cx

CLOCK_EN->MFTx

CLOCK_EN->SPI

CLOCK_EN->UART

CLOCK_EN

->I2Cx

CLOCK_EN->ADC

CLOCK_EN-

>RNG

XO16/32M

XO32K

RC32K

CLK_32K_WDG

CLK_32K_RTC

DIV2

RO16M

16M_CLK

SYS_CLK

CLK_16M_NVM

CLK_16M_UART

CLK_16M_ADC

CLK_16M_I2Cx

CLK_16M_RNG

CLK_APB_BLUE

CLK_16M_SPI

CLK_APB_NVM

CLK_APB_UART

CLK_APB_ADC

CLK_APB_I2Cx

CLK_APB_MFTx

CLK_APB_SPI

CLK_APB_GPIO

CLK_APB_SYSCTRL

CLK_AHB_RNG

CLK_AHB_PKA

CLK_AHB_DMA

CLK_APB_WDG

CLOCK_EN->NVM

CLOCK_EN->UART

CLOCK_EN->SPI

CLK_APB_RTC

CLK_MFTx

CLOCK_EN->GPIO

CLOCK_EN

->SYSCTRL

CLOCK_EN->RNG

CLOCK_EN->PKA

CLOCK_EN->DMA

CLOCK_EN->MFTx

CLOCK_EN->RTC

CLOCK_EN->WDG

CLK_BLUE

Note: When 32 MHz XO is used, the Cortex-M0, the DMA and the APB tree (except for BLE radio access) run at 32

MHz. The rest of the clock tree is divided by two and is at 16 MHz.

The following clocks can be enabled/disabled by software to implement optimal power consumption:

•DMA

•BLE controller

• BLE clock generator

• RNG

• Flash controller

• GPIO

• System controller

• UART

• SPI

• I2C1(1)

• I2C2

• ADC

• MFT1

• MFT2

BlueNRG-2

Clocks and reset management

DS12166 - Rev 7 page 14/169

• RTC

• WDG

•PKA

1. The I2C1 is not available with WLCSP34 package.

By default, all the peripheral APB and AHB clocks are enabled, except for the PKA peripheral. The following

clocks are enabled/disabled automatically:

• Processor clock (disabled in sleep mode)

• RAM clock (disabled if processor clock, SPI clock and BLE clock are all disabled)

Note: It is possible to provide an external 32 kHz signal to the BlueNRG-2 device through the SXTAL0 pin by sourcing

a periodic waveform from 0 to 1.2 V.

3.5.1 Reset management

Figure 7. Reset and wake-up generation shows the general principle of reset. Releasing the reset pin puts

the chip out of shutdown state. The wake-up logic is powered and receives the POR. Each time the wake-up

controller decides to exit sleep or standby modes, it will generate a reset for the core logic. The core logic can

also be reset by:

•Watchdog

• Reset request from the processor (system reset)

• LOCKUP state of the Cortex-M0

The SWD logic is reset by the POR. It is important to highlight that reset pin actually power down chip, so it is not

possible to perform debug access with system under reset.

Figure 7. Reset and wake-up generation

If, for any reason, the users would like to power off the device there are two options:

1. Force RESETN pin to ground, keeping VBAT level

2. To put VBAT pins to ground (e.g. via a transistor)

In the second option, care must be taken to ensure that no voltage is applied to any of the other pins since device

can be powered and having an anomalous power consumption. ST recommendation is to use RESETN whenever

it is possible.

BlueNRG-2

Clocks and reset management

DS12166 - Rev 7 page 15/169

3.5.1.1 Power-on-Reset

The Power-on-Reset (POR) signal is the combination of the POR signal and the BOR signal generated by the

analog circuitry contained in the BlueNRG-2 device. The combination of these signals is used to generate the

input to the Cortex-M0, which is used to reset the debug access port (DAP) of the processor. It is also used to

generate the signal, which resets the debug logic of the Cortex-M0. The POR signal also resets the TAP controller

of the BlueNRG-2 and a part of the Flash controller (managing the Flash memory boot, which does not need to be

impacted by system resets).

The BOR reset is enabled by default. At software level, it can be decided to change the default values after reset.

3.5.1.2 Power-up sequence

The starting sequence of the BlueNRG-2 supply and reset signal is shown below.

Figure 8. BlueNRG-2 power-up sequence

VBATx

X=1,2,3

RESETN

Internal POR

System clock

CPU activity

30 µs

1.82 ms max.

CPU under reset CPU is running on

RCO 16 MHz

CPU can switch on

XO 16/32 MHz by SW

• The VBATx power must only be raised when RESETN pin is low.

•The different VBATx (x=1,2,3) power can be raised separately or together.

• Once the VBATx (x=1, 2, 3) reaches the nominal value, the RESETN pin could be driven high after a 30 us.

• The internal POR is released once internal LDOs are established and RCO clock is ready.

• The system starts on RCO 16 MHz clock system. The software is responsible for configuring the XO 16/32

MHz when necessary.

Note: The minimum negative pulse to reset the system must be at least 30 µs.

BlueNRG-2

Clocks and reset management

DS12166 - Rev 7 page 16/169

The POR circuit is powered by a 1.2 V regulator, which must also be powered up with the correct startup

sequence. Before VBAT has reached the nominal value, RESETN line must be kept low. An external RC circuit

on RESETN pin adds a delay that can prevent RESETN signal from going high before VBAT has reached the

nominal value.

Figure 9. Reset circuit

If the above conditions are not satisfied, ST cannot guarantee the correct operation of the device.

3.5.1.3 Watchdog reset

The BlueNRG-2 contains a watchdog timer, which may be used to recover from software crashes. The watchdog

contains a 32-bit down counter, which generates an interrupt, if the interrupt is not serviced, the watchdog

generates a reset. The watchdog reset resets the Flash controller, the Cortex-M0 and all its peripherals but it does

not reset the debug circuitry of the Cortex-M0.

3.5.1.4 System reset request

The system reset request is generated by the debug circuitry of the Cortex-M0. The debugger writes to the

SYSRESETREQ bit of the “application interrupt and reset control register” (AIRCR). This system reset request

through AIRCR register can also be done by embedded software. The system reset request does not affect the

debugger, thus allowing the debugger to remain connected during the reset sequence.

3.5.1.5 LOCKUP reset

The Cortex-M0 generates an output LOCKUP that indicates that the core is in a deliberate lock-up state resulting

from an unrecoverable exception. The LOCKUP signal is used to generate a reset in the BlueNRG-2, which

affects the Cortex-M0, the Flash controller and all the peripherals.

The LOCKUP signal does not reset the Cortex-M0 debug circuitry and it is not generated if a debugger is

connected.

3.5.2 Reset and wake-up reason decoding

The BlueNRG-2 provides a set of registers to identify the reason behind a reset and wake-up generation. Two

registers are used: CKGEN_SOC->REASON_RST and CKGEN_BLE->REASON_RST. The possible reasons are

listed below:

BlueNRG-2

Clocks and reset management

DS12166 - Rev 7 page 17/169

1. If the register CKGEN_SOC->REASON_RST = 0, according to the CKGEN_BLE->REASON_RST the

possible reasons are:

a. Wake-up from IO9, IO10, IO11, IO12, IO13

b. Wake-up from internal timer: BLE timer 1 or BLE timer 2

c. POR or BOR

2. If the register CKGEN_SOC->REASON_RST is not 0, according to its value the possible reasons are:

a. System reset

b. Watchdog reset

c. Lockup reset

3.5.3 Clock and reset registers

CKGEN_SOC peripheral base address (CKGEN_SOC_BASE_ADDR) 0x40900000.

Table 13. CKGEN_SOC registers

Address offset Name RW Reset Description

0x08 REASON_RST R 0x00000000 Indicates the reset reason from Cortex-M0. Refer to

the detailed description below.

0x1C DIE_ID(1) R0x00000100 Identification information of the device. Refer to the

detailed description below.

0x20 CLOCK_EN RW 0x0003FFFF Enable or gates the APB clock of the peripherals.

Refer to the detailed description below.

0x24 DMA_CONFIG RW 0x00000000 DMA config. Refer to the detailed description below.

0x28 JTAG_IDCODE R 0x0200A041 BlueNRG-2 JTAG IDCODE.

1. It depends on the cut version.

Table 14. CKGEN_SOC - REASON_RST register description: address offset CKGEN_SOC_BASE_ADDR+0x08

Bit Field name Reset RW Description

0 RESERVED 0x0 R RESERVED.

1 SYSREQ 0x0 R Reset caused by Cortex-M0 debug asserting

SYSRESETREQ.

2 WDG 0x0 R Reset caused by assertion of watchdog reset.

3 LOCKUP 0x0 R Reset caused by Cortex-M0 asserting LOCKUP

signal.

31:4 RESERVED 0x0 R RESERVED.

Table 15. CKGEN_SOC - DIE_ID register description: address offset CKGEN_SOC_BASE_ADDR+0x1C

Bit Field name Reset RW Description

3:0 REV 0x0 R Cut revision.

7:4 VERSION 0x0 R Cut version.

11:8 PRODUCT 0x1 R Product.

31:12 RESERVED 0x0 R RESERVED.

BlueNRG-2

Clocks and reset management

DS12166 - Rev 7 page 18/169

Table 16. CKGEN_SOC - CLOCK_EN register description: address offset CKGEN_SOC_BASE_ADDR+0x20

Bit Field name Reset RW Description

0 GPIO 0x1 RW GPIO clock

1 NVM 0x1 RW Flash controller clock

2 SYSCTRL 0x1 RW System controller clock

3 UART 0x1 RW UART clock

4 SPI 0x1 RW SPI clock

6:5 RESERVED 0x3 RW RESERVED

7 WDOG 0x1 RW Watchdog clock

8 ADC 0x1 RW ADC clock

9 I2C1 0x1 RW I2C1 clock

10 I2C2 0x1 RW I2C2 clock

11 MFT1 0x1 RW MFT1 clock

12 MFT2 0x1 RW MFT2 clock

13 RTC 0x1 RW RTC clock

14 SYSCLK_IO_EN 0x1 RW System clock output on IO0 enable bit

15 XO_IO_EN 0x1 RW XO clock output on IO9 enable bit

16 DMA 0x1 RW DMA AHB clock

17 RNG 0x1 RW RNG AHB clock

18 PKA 0x0 RW PKA AHB clock

19 PKA RAM 0x0 RW PKA RAM clock

31:20 RESERVED 0x0 RW RESERVED

Table 17. CKGEN_SOC - DMA_CONFIG register description: address offset CKGEN_SOC_BASE_ADDR+0x24

Bit Field name Reset RW Description

0 ADC_CH0 0x0 RW Select ADC on DMA channel 0 instead of peripheral.

1 ADC_CH1 0x0 RW Select ADC on DMA channel 1 instead of peripheral.

2 ADC_CH2 0x0 RW Select ADC on DMA channel 2 instead of peripheral.

3 ADC_CH3 0x0 RW Select ADC on DMA channel 3 instead of peripheral

4 ADC_CH4 0x0 RW Select ADC on DMA channel 4 instead of peripheral.

5 ADC_CH5 0x0 RW Select ADC on DMA channel 5 instead of peripheral.

6 ADC_CH6 0x0 RW Select ADC on DMA channel 6 instead of peripheral.

7 ADC_CH7 0x0 RW Select ADC on DMA channel 7 instead of peripheral.

31:8 RESERVED 0x0 RW RESERVED

Note: Only one DMA channel for the ADC should be selected at time. Hardware does not prevent selecting more than

one DMA channel for ADC.

Table 18. CKGEN_SOC - JTAG_IDCODE register description: address offset CKGEN_SOC_BASE_ADDR+0x28

Bit Field name Reset RW Description

0 RESERVED 0x1 R RESERVED

11:1 MANUF_ID 0x020 R Manufacturer ID

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Clocks and reset management

DS12166 - Rev 7 page 19/169

Bit Field name Reset RW Description

27:12 PART_NUMBER 0x200A R Part number

31:28 VERSION_NUM 0x0 R Version

CKGEN_BLE peripheral base address (CKGEN_BLE_BASE_ADDR) 0x48100000.

Table 19. CKGEN_BLE registers

Address offset Name RW Reset Description

0x08 REASON_RST R 0x00000005 Indicates the Reset reason from BLE. Refer to the

detailed description below.

0x0C CLK32K_COUNT RW 0x0000000F Counter of 32 kHz clock. Refer to the detailed

description below.

0x10 CLK32K_PERIOD R 0x00000000 Period of 32 kHz clock. Refer to the detailed

description below.

0x14 CLK32K_FREQ R 0x00000000 Measurement of frequency of 32 kHz clock. Refer to

the detailed description below.

0x18 CLK32K_IT RW 0x00000000 Interrupt event for 32 kHz clock measurement. Refer

to the detailed description below.

Table 20. CKGEN_BLE - REASON_RST register description: address offset CKGEN_BLE_BASE_ADDR+0x08

Bit Field name Reset RW Description

0 RESERVED 0x1 R RESERVED

1 BOR 0x0 R Reset from BOR

2 POR 0x1 R Reset from POR

3 WKP_IO9 0x0 R Wake-up from external IO9

4 WKP_IO10 0x0 R Wake-up from external IO10

5 WKP_IO11 0x0 R Wake-up from external IO11

6 WKP_IO12 0x0 R Wake-up from external IO12

7 WKP_IO13 0x0 R Wake-up from external IO13

8 WKP_BLUE 0x0 R Wake-up comes from the timer 1 expiration in the

wake-up control block of the BLE radio

10 WKP2_BLUE 0x0 R Wake-up comes from the timer 2 expiration in the

wake-up control block of the BLE radio

31:11 RESERVED 0x0 R RESERVED

Table 21. CKGEN_BLE - CLK32K_COUNT register description: address offset CKGEN_BLE_BASE_ADDR+0x0C

Bit Field name Reset RW Description

8:0 SLOW_COUNT 0xF RW Program the window length (in slow clock period unit)

for slow clock measurement

31:9 RESERVED 0x0 RW RESERVED

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Clocks and reset management

DS12166 - Rev 7 page 20/169

Table 22. CKGEN_BLE - CLK32K_PERIOD register description: address offset CKGEN_BLE_BASE_ADDR+0x10

Bit Field name Reset RW Description

18:0 SLOW_PERIOD 0x0 R

Indicates slow clock period information. The result

provided in this field corresponds to the length

of SLOW_COUNT periods of the slow clock (32

kHz) measured in 16 MHz half-period unit. The

measurement is done automatically each time the

device enters in active2 mode using SLOW_COUNT

= 16. A new calculation can be launched by writing

zero in CLK32K_PERIOD register. In this case,

the time window uses the value programmed in

SLOW_COUNT field.

31:19 RESERVED 0x0 R RESERVED

Table 23. CKGEN_BLE - CLK32K_FREQ register description: address offset CKGEN_BLE_BASE_ADDR+0x14

Bit Field name Reset RW Description

26:0 SLOW_FREQ 0x0 R Value equal to 239 / SLOW_PERIOD

31:27 RESERVED 0x0 R RESERVED

Table 24. CKGEN_BLE - CLK32K_IT register description: address offset CKGEN_BLE_BASE_ADDR+0x18

Bit Field name Reset RW Description

0 CLK32K_MEAS_IRQ 0x0 RW

When read, provides the status of the interrupt

indicating slow clock measurement is finished:

0: No pending interrupt.

1: Pending interrupt.

When written, clears the interrupt:

0: No effect.

1: Clear the interrupt.

31:1 RESERVED 0x0 RW RESERVED

Note: All RESERVED fields inside registers must always be written with their default value.

3.6 ADC

3.6.1 Introduction

The BlueNRG-2 integrates a 10-bit analog-to-digital converter (ADC) for sampling an external signal.

Main features are:

•Sampling frequency 1 MHz

•One channel in single ended or differential input through the pins ADC1 and ADC2

• Temperature and battery voltage sensors

• The conversion are either continuous or single step acquisition

• An integrated digital filter is used to process a PDM data stream from a MEMS microphone

3.6.2 Functional overview

The figure below shows a top diagram of the ADC.

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ADC

DS12166 - Rev 7 page 21/169

Figure 10. ADC block diagram

TEMP

VBATSENS

ADC1 pin

InP

InN

DOWNSAMPLE

FILTERS

ADC ADC_CLK

ADC_DATA

CLK

MIC_SEL

CONV_DATA

CLK to external

microphone

(1.6 MHz or 800 kHz)

PDM signal from

external microphone

PGA

ADC2 pin

PGA

CHSEL PDM_CLK PDM_DATA

VREF

Several channels are available for the conversion, the CHSEL selects the channel according to Table 25. ADC

channels.

Table 25. ADC channels

CHSEL Channels description

0 All switch open. No input

1 Single ended through ADC2 pin. InP = VREF (internal), InN = ADC2 pin

2 Single ended through ADC1 pin. InP = ADC1 pin, InN = VREF (internal)

3 Differential ADC1 pin – ADC2 pin. InP = ADC1 pin, InN = ADC2 pin

4 Temperature sensor. InN=TEMP, InP = 0.6 V (internal)

5 Battery voltage sensor. InN = VBATSENS, InP = 0.6 V (internal)

6 Short. InP = InN = 0.6 V (internal)

The conversion can be single (CONT = 0) or continuous (CONT = 1). In continuous mode, the conversion

runs with a pre-programmed sampling rate, the user must discard the first samples that are not valid because

generated during the establishment of the internal filter. In particular, it must discards a number of samples as

follows:

• 10 samples if the bitfield SKIP is 0 (COMP filter not bypassed)

• 3 samples if the bitfield SKIP is 1 (COMP filter bypassed)

In single step mode the ADC performs a conversion and then stops.

The output data rate depends on the setting of OSR according to the following table.

Table 26. ADC data rate

OSR Output data rate [Ksample/s]

0 (200) 5

1 (100) 10

2 (64) 15.625

3 (32) 31.25

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The setting of the oversampling ratio (OSR) must be done according to the frequency of the input signal (AC),

while for DC signals, the best performance is with OSR = 200. In order to achieve the best performance within

the selected input voltage range, the attenuation value must be set through the corresponding register PGASEL

value, as in the following table.

Table 27. ADC parameter settings

Vin range [V] Attenuation [dB] REFSEL value PGASEL value

[0, 1.2] 0 2 0

[0, 2.4] 6.02 2 1

[0, 3.6] 9.54 2 2

The impedance of the ADC input pins is programmable through the register PGASEL as shown in the following

table:

Table 28. Impedance of the ADC pin

PGASEL value Attenuation [dB] Input impedance[kΩ]

0 0 HiZ

1 6.02 520

2 9.54 585

Note: In order to reduce leakage from the ADC pins, the PGASEL register must be set to 0 if the ADC is not used,

regardless the ADC is ON or OFF.

3.6.2.1 ADC microphone mode

The system can work in conjunction with an external MEMS microphone. In this mode the user must configure:

• an IO as PDM_CLK (GPIO Serial2 mode) in order to provide the clock signal to an external MEMS

microphone (output signal)

•an IO as PDM_DATA (GPIO Serial2 mode) in order to receive and process the PDM data stream from the

external MEMS microphone (input signal). See Table 130. IO functional map for more details about how

these pins can be used for this mode.

• set the MIC_SEL bitfield of the CONF register, in order to provide a clock to the MEMS microphone. The

PDM_CLK signal provides a clock that can be 1.6 MHz (DIG_FILT_CLK = 0) or 0.8 MHz (DIG_FILT_CLK

=1)

• set the MIC_ON bitfield of the CTRL register, in order to make the ADC start the conversion from the MEMS

microphone

Note: MIC_ON and ON bitfields must be exclusive and must not be set together.

The output data rate changes with the OSR and according to the clock frequency provided as explained in

Table 29. Output data rate with microphone.

Table 29. Output data rate with microphone

DIG_FILT_CLK OSR Output data rate

[Ksample/s]

1 (clock = 0.8 MHz)

0 (200) 4

1 (100) 8

2 (64) 12.5

3 (32) 25

0 (clock = 1.6 MHz)

0 (200) 8

1 (100) 16

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DIG_FILT_CLK OSR Output data rate

[Ksample/s]

0 (clock = 1.6 MHz) 2 (64) 25

3 (32) 50

3.6.2.2 ADC start conversion

The ADC both analog and digital sub-system are switched on by setting ADCON and SWSTART.

The conversion operation consists of four phases.

1. The wake-up phase lasts 6 µs, is present at the beginning of a single acquisition, with the goal to let the

analog system to settle before to start the acquisition.

2. When CALEN bit and AUTO_OFFSET are set in ADC_CTRL register, a calibration starts. It permits to

compensate the offset in the analog part. The conversion status is tracked by SR status register. At the

beginning of the conversion the BUSY bit is set and masks any attempt to change CONF, up to the end of

the conversion. At end of this conversion, the ENDCAL flag is generated and the OFFSET register is written

with the converted offset voltage.

3. The acquisition phase is regulated by a timeout depending on the resolution. In this phase, digital filter chain

processes the data coming from ADC.

4. The elaboration phase is at the end of the timeout, the data obtained at the output of the digital filter is

written in the DATA register. The content of the OFFSET register is automatically used to compensate

the final result. Furthermore, the ADCEOC flag is generated to warn about the end of conversion. If

ENAB_COMP bit is set, the WDOG flag is generated to warn that the result of the conversion is between a

high THRESHOLD_HI and low threshold THRESHOLD_LO.

Note: It is always advisable to set the register fields CALEN and AUTO_OFFSET in order to perform automatic

calibration for each measurement.

3.6.2.3 ADC offset

The ADC automatically corrects a potential offset error by taking into account the content of the register OFFSET.

To enable the automatic offset correction the CALEN and the AUTO_OFFSET must be both set. The result of the

calibration is stored in the OFFSET register.

The correction of the offset can be also done manually, for example by performing firstly an automatic offset

calibration by making an ADC conversion with both AUTO_OFFSET and CALEN bitfields set. In this way, the

OFFSET register is updated with the current offset error. Then, the automatic offset calibration can be disabled

by set to 0b the AUTO_OFFSET and the CALEN bitfields. And so, the offset value is applied to all the next ADC

conversions.

The calibration value is a 16-bit value in the register OFFSET. It must be placed in the bitfield OFFSET_MSB if

the bitfield SKIP is 0 (filter not bypassed). While, if the bitfield SKIP is 1 (filter bypassed), the calibration value

must be placed in the bitfield OFFSET_LSB.

3.6.2.4 ADC conversion

The relationship between differential input voltage and ADCRAW code (first 16-bit MSB of DATA_CONV register)

depends on a limited set of parameters: the digital core power supply VDD1V2, the PGA value, and a scaling

factor.

Differential mode

This mode enables the ADC differential conversion from the pins ADC1 and ADC2.

VADC12 Volt =VADC1− VADC2= 1 + PGASEL *ADCRAW

FS_16 OSR 2*VDD1V2(1)

Single-ended mode

This mode enables the ADC conversion from the pin ADC1 or from the pin ADC2.

VADC1Volt = 1+PGASEL *VREF +ADCRAW

FS_16 OSR *2*VDD1V2(2)

VADC2Volt = 1+PGASEL *VREF − ADCRAW

FS_16 OSR *2*VDD1V2(3)

Battery voltage sensor

This mode enables the monitoring of the battery voltage VBATT, through an internal resistive bridge.

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ADC

DS12166 - Rev 7 page 24/169

VBATT Volt =KBATT*VREF − ADCRAW

FS_16 OSR *2*VDD1V2(4)

Temperature sensor

This mode enables the monitoring of the temperature by means of an internal sensor, with the following voltage to

temperature conversion:

VTEMP °C=KTC*VREF − ADCRAW

FS_16 OSR *2*VDD1V2 + OFFSETTC (5)

To ensure an accurate temperature reading, average the value over several readings.

Below the values for the symbols used in the ADC conversion formulas:

•PGASEL is the input attenuation register, values: 0, 1, or 2

• FS_16(OSR) is the full scale factor for ADCRAW and it depends on the oversampling ratio (OSR) as shown

below:

• If SKIP is 0 (filter not bypassed), then:

– ADCRAW is DATA_CONV_MSB

– FS_16(32) = FS_16(64) = 35442

– FS_16(100) = FS_16(200) = 41260

• If SKIP is 1 (filter bypassed), then:

– ADCRAW is DATA_CONV_LSB

– FS_16(32) = FS_16(64) = 32768

– FS_16(100) = FS_16(200) = 38147

• VDD1V2 is the digital core power supply = 1.2 V

• VREF is given by the register REFSEL, with a typical value of 0.6 V

• KBATT is 4.36

• KTC is 401

• OFFSETTC is 267 °C

3.6.3 ADC registers

ADC peripheral base address (ADC_BASE_ADDR) 0x40800000.

Table 30. ADC registers

Address offset Name RW Reset Description

0x00 CTRL RW 0x00000000 ADC control register. Refer to the

detailed description below.

0x04 CONF RW 0x0000000C ADC configuration register. Refer to the

detailed description below.

0x08 IRQSTAT R 0x00000000 IRQ masked status register. Refer to the

detailed description below.

0x0C IRQMASK RW 0x0000000F It sets the mask for ADC interrupt. Refer

to the detailed description below.

0x10 IRQRAW R 0x00000000 IRQ status register. Refer to the detailed

description below.

0x14 DATA_CONV R 0x00000000 Result of the conversion in two

complement format.

0x18 OFFSET RW 0x00000000 Offset for correction of converted data

0x20 SR_REG RW 0x00000000 ADC status register. Refer to the

detailed description below.

0x24 THRESHOLD_HI RW 0xFFFFFFFF High threshold for window comparator.

0x28 THRESHOLD_LO RW 0x00000000 Low threshold for window comparator.

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Table 31. ADC - CTRL register description: address offset ADC_BASE_ADDR+0x00

Bit Field name Reset RW Description

0 ON 0x0 RW

Starts ADC analog subsystem. This bit

must be set before starting a conversion.

0: ADC is OFF.

1: ADC is ON.

This bit works for all the mode except

the microphone mode.

1 CALEN 0x0 RW

The automatic calibration routine is

enabled if both AUTO_OFFSET and

CALEN bitfields are set. The result of

the calibration is placed in the OFFSET

value.

0: disable the automatic calibration

1: enable the automatic calibration

This bitfield can be set to 0 only by

setting to 1 the bitfield RSTCALEN

2 SWSTART 0x0 RW

Starts the ADC conversion phase when

set.

This bit works for all the mode except

the microphone mode.

3 RESET 0x0 RW

Reset all the ADC APB registers

when set (CTRL, CONF, DATA_CONV,

THRESHOLD_HI, THRESHOLD_LO).

This bit is auto-cleared by the hardware

so it is always read 0

4 STOP 0x0 RW

Permits the continuous conversion to be

stopped.

1: stop the continuous conversion and

switch off the ADC.

The bitfields SWSTART, ON, DMA_EN

and MIC_ON are auto-cleared if set.

This bit is auto-cleared by the hardware

so it is always read at 0.

5 ENAB_COMP 0x0 RW

Enables the window comparator when

set to 1. WDOG flag is ADC_SR register

is set if the converted value is between

THRESHOLD_HI and THRESHOLD_LO

value.

6 RSTCALEN 0x0 RW

Disable the calibration phase when set

to 1. This bit has to be set to disable

the calibration each time calibration is

enabled. This bit is auto-cleared by the

hardware so it is always read at 0.

7 AUTO_OFFSET 0x0 RW

The automatic calibration routine is

enabled if both AUTO_OFFSET and

CALEN bitfields are set. The result of

the calibration is placed in the OFFSET

value.

0: disable the automatic calibration.

1: enable the automatic calibration.

8 MIC_ON 0x0 RW

Starts ADC analog subsystem for

microphone mode only.

0: ADC is OFF

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Bit Field name Reset RW Description

1: ADC is ON

9 DMA_EN 0x0 RW

Enables the DMA.

0: DMA is disabled.

1: DMA is enabled.

31:10 RESERVED 0x0 RW RESERVED

Table 32. ADC - CONF register description: address offset ADC_BASE_ADDR+0x04

Bit Field name Reset RW Description

0 RESERVED 0x0 RW RESERVED

3:1 CHSEL 0x6 RW

Select the input channel:

000b: All switches open.

001b: Single-ended through ADC2 pin. InP = VREF

(internal), InN = ADC2 pin.

010b: Single-ended through ADC1 pin. InP = ADC1 pin,

InN = VREF (internal).

011b: Differential ADC1 pin - ADC2 pin, InP = ADC1 pin,

InN = ADC2 pin.

100b: Temperature sensor. InP = 0.6 V (internal), InN =

TEMP.

101b: Battery voltage sensor. InP = 0.6 V (internal), InN =

VBATSENS.

110b: Short InN = InP = 0.6 V (internal).

5:4 REFSEL 0x0 RW

Set the VREF for single ended conversion:

00b: 0.0 V (default value not recommended)

10b: 0.6 V (suggested value)

7:6 OSR 0x0 RW

Set the oversampling ratio.

00b: Set the oversampling ratio to 200 (1)

01b: Set the oversampling ratio to 100

10b: Set the oversampling ratio to 64

11b: Set the oversampling ratio to 32

9:8 PGASEL 0x0 RW

Set the input attenuator value:

00b: Input attenuator at 0 dB

01b: Input attenuator at 6.02 dB

10b: Input attenuator at 9.54 dB

10 RESERVED 0x0 RW RESERVED

11 CONT 0x0 RW

Enable the continuous conversion mode:

0: Single conversion

1: Continuous conversion

17:12 RESERVED 0x00 RW RESERVED

18 SKIP 0x0 RW

It permits the filter COMP to be bypassed to speed up the

conversion for signal at low frequency:

0: Filter not bypassed

1: Filter bypassed

According to the value of this bitfield, the behavior of the

ADC changes as follows:

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DS12166 - Rev 7 page 27/169

Bit Field name Reset RW Description

- If SKIP is 0: the first 10 converted samples in ADC mode

continuous should be discarded by the user. The converted

date is in the bitfield DATA_CONV_MSB. The calibration

result is in the bitfield OFFSET_MSB.

- If SKIP is 1: the first 3 converted samples in ADC mode

continuous should be discarded by the user. The converted

date is in the bitfield DATA_CONV_LSB. The calibration

result is in the bitfield OFFSET_LSB.

So, a calibration must be redone if the SKIP bitfield value

changes.

19 RESERVED 0x0 RW RESERVED

20 DIG_FILT_CLK 0x0 RW

Frequency clock selection value on PDM_CLK when

MIC_SEL=1:

0: 1.6 MHz

1: 0.8 MHz

21 RESERVED 0x0 RW RESERVED

22 MIC_SEL 0x0 RW

Provides the clock on GPIO:

0: Do not provided any external clock source

1: Provide clock source from GPIO

31:23 RESERVED 0x000 RW RESERVED

1. Best value for sampling DC signals.

Table 33. ADC - IRQSTAT register description: address offset ADC_BASE_ADDR+0x08

Bit Field name Reset RW Description

0 ENDCAL 0x0 R 1: When the calibration is completed. Clear on register

read.

1 RESERVED 0x0 R RESERVED

2 EOC 0x0 R 1: When the conversion is completed. Clear on register

read.

3 WDOG 0x0 R

If ENAB_COMP = 1, this bit indicates the result of the

conversion is between high and low threshold:

0: DATA_CONV is NOT between THRESHOLD_HI and

THRESHOLD_LO values.

1: DATA_CONV is between THRESHOLD_HI and

THRESHOLD_LO values.

This field is updated on each new end of conversion event

related to the converted data value.

Clear on register read.

31:4 RESERVED 0x0 R RESERVED

Table 34. ADC - IRQMASK register description: address offset ADC_BASE_ADDR+0x0C

Bit Field name Reset RW Description

0 ENDCAL 0x1 RW

Interrupt mask for the end of calibration event:

0: Interrupt is enabled.

1: Interrupt is disabled.

1 RESERVED 0x1 RW RESERVED

2 EOC 0x1 RW Interrupt mask for the end of conversion event:

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DS12166 - Rev 7 page 28/169

Bit Field name Reset RW Description

0: Interrupt is enabled.

1: Interrupt is disabled.

3 WDOG 0x1 RW

Interrupt mask for the within the threshold event:

0: Interrupt is enabled.

1: Interrupt is disabled.

31:4 RESERVED 0x0 RW RESERVED

Table 35. ADC - IRQRAW register description: address offset ADC_BASE_ADDR+0x10

Bit Field name Reset RW Description

0 ENDCAL 0x0 R 1: When the calibration is completed. Clear on register

read.

1 RESERVED 0x0 R RESERVED

2 EOC 0x0 R 1: When the conversion is completed. Clear on register

read.

3 WDOG 0x0 R

If ENAB_COMP = 1, this bit indicates the result of the

conversion is between high and low threshold:

0: DATA_CONV is NOT between THRESHOLD_HI and

THRESHOLD_LO values.

1: DATA_CONV is between THRESHOLD_HI and

THRESHOLD_LO values.

This field is updated on each new end of conversion event

related to the converted data value.

Clear on register read.

31:4 RESERVED 0x0 R RESERVED

Table 36. ADC - DATA_CONV register description: address offset ADC_BASE_ADDR+0x14

Bit Field name Reset RW Description

31:16 DATA_CONV_MS

B0x0000 R

Result of the conversion in two

complement format. If the filter is

not bypassed, the bitfield SKIP is

0, the DATA_CONV_LSB is negligible

and the ADC converted data is the

DATA_CONV_MSB.

15:0 DATA_CONV_LSB 0x0000 R

Result of the conversion in two

complement format. If the filter is

bypassed, the bitfield SKIP is 1, the

DATA_CONV_MSB is negligible and the

ADC converted data is the value of

DATA_CONV_LSB * 1.08 (corrective

factor).

Table 37. ADC - OFFSET register description: address offset ADC_BASE_ADDR+0x18

Bit Field name Reset RW Description

31:16 OFFSET_MSB 0x0000 RW

Offset for correction of converted data. If

the bitfield SKIP is 0, the 16-bit offset is

in the MSB part of the register.

15:0 OFFSET_LSB 0x0000 RW

Offset for correction of converted data. if

the bitfield SKIP is 1, the 16-bit offset is

in the LSB part of the register.

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Table 38. ADC - SR_REG register description: address offset ADC_BASE_ADDR+0x20

Bit Field name Reset RW Description

0 RESERVED 0x0 RW RESERVED

1 BUSY 0x0 RW 1: during conversion.

31:2 RESERVED 0x0 RW RESERVED

Table 39. ADC - THRESHOLD_HI register description: address offset ADC_BASE_ADDR+0x24

Bit Field name Reset RW Description

31:0 THRESHOLD_HI 0xFFFFFFFF RW High threshold for window comparator.

Table 40. ADC - THRESHOLD_LO register description: address offset ADC_BASE_ADDR+0x28

Bit Field name Reset RW Description

31:0 THRESHOLD_LO 0x00000000 RW Low threshold for window comparator.

Note: All RESERVED fields inside registers must always be written with their default value.

3.7 DMA

3.7.1 Introduction

The BlueNRG-2 device embeds a DMA allowing various combination of data transfer between the memory and

the peripherals without CPU intervention.

Main features are:

•Eight independently configurable channels connected to dedicated hardware DMA requests; software trigger

is also supported.

•Priorities between requests from channels of the DMA are software programmable (four levels consisting of

very high, high, medium, low). When two channels with same software priority need attention, channel with

lower hardware index will take priority.

• Independent source and destination transfer size (byte, half word, word), emulating packing and unpacking.

• Support for circular buffer management.

• Event flags (DMA half transfer, DMA transfer complete), logically ORed together in a single interrupt request

for each channel.

• Memory-to-memory transfer (RAM only), peripheral-to-memory and memory-to-peripheral, and peripheral-to-

peripheral transfers.

• Programmable number of data to be transferred up to 65536 bytes.

3.7.2 Functional overview

The DMA controller performs direct memory transfer by sharing the system bus with the other masters of the

device. The DMA request may stop the CPU access to the system bus for some bus cycles, when the CPU

and DMA are targeting the same destination (memory or peripheral). The bus matrix implements round-robin

scheduling, thus ensuring at least half of the system bus bandwidth (both to memory and peripheral) for the CPU.

3.7.2.1 DMA transactions

After an event, the peripheral sends a request signal to the DMA controller. The DMA controller serves the

request depending on the channel priorities. As soon as the DMA controller accesses the peripheral, the DMA

controller sends an acknowledge to the peripheral. The peripheral releases its request as soon as it gets the

acknowledge from the DMA controller. Once the request is deasserted by the peripheral, the DMA controller

releases the acknowledge. If there are more requests, the peripheral can initiate the next transaction.

In summary, each DMA transfer consists of three operations:

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• The loading of data from the peripheral data register or a location in memory addressed through an

internal current peripheral/memory address register. The start address used for the first transfer is the base

peripheral/memory address programmed in the DMA_CPARx or DMA_CMARx register.

• The storage of the data loaded to the peripheral data register or a location in memory addressed through an

internal current peripheral/memory address register. The start address used for the first transfer is the base

peripheral/memory address programmed in the DMA_CPARx or DMA_CMARx register.

• The post-decrementing of the DMA_CNDTRx register, which contains the number of transactions that have

still to be performed.

3.7.2.2 Arbiter

The arbiter manages the channel requests based on their priority and launches the peripheral/memory access

sequences.

The priorities are managed in two stages:

•Software: each channel priority can be configured in the DMA_CCRx register. There are four levels:

–Very high priority

– High priority

– Medium priority

– Low priority

• Hardware: if two requests have the same software priority level, the channel with the lowest number has the

priority versus the channel with the highest number. For example, channel 2 gets priority over channel 4.

3.7.2.3 DMA channels

Each channel can handle DMA transfer between a peripheral register located at a fixed address and a memory

address. The amount of data to be transferred (up to 65535) is programmable. The register, which contains the

amount of data items to be transferred, is decremented after each transaction.

Programmable data sizes

Transfer data sizes of the peripheral and memory are fully programmable through the PSIZE and MSIZE bits in

the DMA_CCRx register.

Pointer increments

Peripheral and memory pointers can optionally be automatically post-incremented after each transaction

depending on the PINC and MINC bits in the DMA_CCRx register. If incremented mode is enabled, the address

of the next transfer will be the address of the previous one incremented by 1, 2 or 4 depending on the chosen

data size. The first transfer address is the one programmed in the DMA_CPARx/DMA_CMARx registers. During

transfer operations, these registers keep the initially programmed value. The current transfer addresses (in the

current internal peripheral/memory address register) are not accessible by software. If the channel is configured

in non-circular mode, no DMA request is served after the last transfer (that is once the number of data items

to be transferred has reached zero). In order to reload a new number of data items to be transferred into the

DMA_CNDTRx register, the DMA channel must be disabled.

If a DMA channel is disabled, the DMA registers are not Reset. The DMA channel registers (DMA_CCRx,

DMA_CPARx and DMA_CMARx) retain the initial values programmed during the channel configuration phase.

In circular mode, after the last transfer, the DMA_CNDTRx register is automatically reloaded with the initially

programmed value. The current internal address registers are reloaded with the base address values from the

DMA_CPARx/DMA_CMARx registers.

Channel configuration procedure

The following sequence should be followed to configure a DMA channelx (where x is the channel number).

1. Set the peripheral register address in the DMA_CPARx register. The data are moved from/ to this address

to/ from the memory after the peripheral event.

2. Set the memory address in the DMA_CMARx register. The data will be written to or read from this memory

after the peripheral event.

3. Configure the total number of data to be transferred in the DMA_CNDTRx register. After each peripheral

event, this value is decremented.

4. Configure the channel priority using the PL[1:0] bits in the DMA_CCRx register.

5. Configure data transfer direction, circular mode, peripheral and memory incremented mode, peripheral and

memory data size, and interrupt after half and/or full transfer in the DMA_CCRx register.

6. Activate the channel by setting the ENABLE bit in the DMA_CCRx register.

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As soon as the channel is enabled, it can serve any DMA request from the peripheral connected on the channel.

Once half of the bytes are transferred, the half-transfer flag (HTIF) is set and an interrupt is generated if the

half-transfer interrupt enable bit (HTIE) is set. At the end of the transfer, the transfer complete flag (TCIF) is set

and an interrupt is generated if the transfer complete interrupt enable bit (TCIE) is set.

Circular mode

Circular mode is available to handle circular buffers and continuous data flows (e.g. ADC scan mode). This

feature can be enabled using the CIRC bit in the DMA_CCRx register. When circular mode is activated, the

number of data to be transferred is automatically reloaded with the initial value programmed during the channel

configuration phase, and the DMA requests continue to be served.

Memory-to-memory mode

The DMA channels can also work without being triggered by a request from a peripheral. This mode is called

memory-to-memory mode. If the MEM2MEM bit in the DMA_CCRx register is set, then the channel initiates

transfers as soon as it is enabled by software by setting the Enable bit (EN) in the DMA_CCRx register. The

transfer stops once the DMA_CNDTRx register reaches zero. Memory-to-Memory mode may not be used at the

same time as Circular mode.

3.7.2.4 Programmable data width, data alignment and endianness

When PSIZE and MSIZE are not equal, the DMA performs some data alignments as described in

Table 41. Programmable data width and endian behavior (when bits PINC = MINC = 1): Programmable data

width & endian behavior (when bits PINC = MINC = 1).

Table 41. Programmable data width and endian behavior (when bits PINC = MINC = 1)

Source

port

width

Destination

port width

Number of

data items

to transfer

(NDT)

Source content:

address/data Transfer operations

Destination

content:

address/data

8 8 4

@0x0 / B0 1: READ B0[7:0] @0x0 then WRITE

B0[7:0] @0x0 @0x0 / B0

@0x1 / B1 2: READ B1[7:0] @0x1 then WRITE

B0[7:0] @0x1 @0x1 / B1

@0x2 / B2 3: READ B2[7:0] @0x2 then WRITE

B0[7:0] @0x2 @0x2 / B2

@0x3 / B3 4: READ B3[7:0] @0x3 then WRITE

B0[7:0] @0x3 @0x3 / B3

8 16 4

@0x0 / B0 1: READ B0[7:0] @0x0 then WRITE

00B0[15:0] @0x0 @0x0 / 00B0

@0x1 / B1 2: READ B1[7:0] @0x1 then WRITE

00B0[15:0] @0x2 @0x2 / 00B1

@0x2 / B2 3: READ B2[7:0] @0x2 then WRITE

00B0[15:0] @0x4 @0x4 / 00B2

@0x3 / B3 4: READ B3[7:0] @0x3 then WRITE

00B0[15:0] @0x6 @0x6 / 00B3

8 32 4

@0x0 / B0 1: READ B0[7:0] @0x0 then WRITE

000000B0[31:0] @0x0 @0x0 / 000000B0

@0x1 / B1 2: READ B1[7:0] @0x1 then WRITE

000000B0[31:0] @0x4 @0x4 / 000000B1

@0x2 / B2 3: READ B2[7:0] @0x2 then WRITE

000000B0[31:0] @0x8 @0x8 / 000000B2

@0x3 / B3 4: READ B3[7:0] @0x3 then WRITE

000000B0[31:0] @0xC @0xC / 000000B3

16 8 4

@0x0 / B1B0 1: READ B1B0[15:0] @0x0 then WRITE

B0[7:0] @0x0 @0x0 / B0

@0x1 / B3B2 2: READ B3B2[15:0] @0x2 then WRITE

B0[7:0] @0x1 @0x1 / B2

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Source

port

width

Destination

port width

Number of

data items

to transfer

(NDT)

Source content:

address/data Transfer operations

Destination

content:

address/data

16 8 4

@0x2 / B5B4 3: READ B5B4[15:0] @0x4 then WRITE

B0[7:0] @0x2 @0x2 / B4

@0x3 / B7B6 4: READ B7B6[15:0] @0x6 then WRITE

B0[7:0] @0x3 @0x3 / B6

16 16 4

@0x0 / B1B0 1: READ B1B0[15:0] @0x0 then WRITE

B1B0[15:0] @0x0 @0x0 / B1B0

@0x1 / B3B2 2: READ B3B2[15:0] @0x2 then WRITE

B3B2[15:0] @0x2 @0x2 / B3B2

@0x2 / B5B4 3: READ B5B4[15:0] @0x4 then WRITE

B5B4[15:0] @0x4 @0x4 / B5B4

@0x3 / B7B6 4: READ B7B6[15:0] @0x6 then WRITE

B7B6[15:0] @0x6 @0x6 / B7B6

16 32 4

@0x0 / B1B0 1: READ B1B0[15:0] @0x0 then WRITE

0000B1B0[31:0] @0x0 @0x0 / 0000B1B0

@0x1 / B3B2 2: READ B3B2[15:0] @0x2 then WRITE

0000B3B2[31:0] @0x4 @0x4 / 0000B3B2

@0x2 / B5B4 3: READ B5B4[15:0] @0x4 then WRITE

0000B5B4[31:0] @0x8 @0x8 / 0000B5B4

@0x3 / B7B6 4: READ B7B6[15:0] @0x6 then WRITE

0000B7B6[31:0] @0xC

@0xC /

0000B7B6

32 8 4

@0x0 /

B3B2B1B0

1: READ B3B2B1B0[31:0] @0x0 then

WRITE B0[7:0] @0x0 @0x0 / B0

@0x4 /

B7B6B5B4

2: READ B7B6B5B4[31:0] @0x4 then

WRITE B0[7:0] @0x1 @0x1 / B4

@0x8 /

BBBAB9B8

3: READ BBBAB9B8[31:0] @0x8 then

WRITE B0[7:0] @0x2 @0x2 / B8

@0xC /

BFBEBDBC

4: READ BFBEBDBC[31:0] @0xC then

WRITE B0[7:0] @0x3 @0x3 / BC

32 16 4

@0x0 /

B3B2B1B0

1: READ B3B2B1B0[31:0] @0x0 then

WRITE B1B0[15:0] @0x0 @0x0 / B1B0

@0x4 /

B7B6B5B4

2: READ B7B6B5B4[31:0] @0x4 then

WRITE B3B2[15:0] @0x2 @0x2 / B5B4

@0x8 /

BBBAB9B8

3: READ BBBAB9B8[31:0] @0x8 then

WRITE B5B4[15:0] @0x4 @0x4 / B9B8

@0xC /

BFBEBDBC

4: READ BFBEBDBC[31:0] @0xC then

WRITE B7B6[15:0] @0x6 @0x6 / BDBC

32 32 4

@0x0 /

B3B2B1B0

1: READ B3B2B1B0[31:0] @0x0 then

WRITE 0000B1B0[31:0] @0x0

@0x0 /

B3B2B1B0

@0x4 /

B7B6B5B4

2: READ B7B6B5B4[31:0] @0x4 then

WRITE 0000B3B2[31:0] @0x4

@0x4 /

B7B6B5B4

@0x8 /

BBBAB9B8

3: READ BBBAB9B8[31:0] @0x8 then

WRITE 0000B5B4[31:0] @0x8

@0x8 /

BBBAB9B8

@0xC /

BFBEBDBC

4: READ BFBEBDBC[31:0] @0xC then

WRITE 0000B7B6[31:0] @0xC

@0xC /

BFBEBDBC

The DMA is addressed through AHB and can be accessed only with 32-bit access. Any 8-bit or 16-bit access will

generate a hard fault.

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When the DMA initiates an AHB byte or halfword write operation, the data are duplicated on the unused lanes

of the HWDATA[31:0] bus. So when the used AHB slave peripheral does not support byte or halfword write

operations (when HSIZE is not used by the peripheral) and does not generate any error, the DMA writes the 32

HWDATA bits as shown in the two examples below:

• To write the halfword “0xABCD”, the DMA sets the HWDATA bus to “0xABCDABCD” with HSIZE = HalfWord

• To write the byte “0xAB”, the DMA sets the HWDATA bus to “0xABABABAB” with HSIZE = byte

Assuming that the AHB/APB bridge is an AHB 32-bit slave peripheral that does not take the HSIZE data into

account, it will transform any AHB byte or halfword operation into a 32-bit APB operation in the following manner:

• an AHB byte write operation of the data “0xB0” to 0x0 (or to 0x1, 0x2 or 0x3) is converted to an APB word

write operation of the data “0xB0B0B0B0” to 0x0

• an AHB half-word write operation of the data “0xB1B0” to 0x0 (or to 0x2) is converted to an APB word write

operation of the data “0xB1B0B1B0” to 0x0

3.7.2.5 Error management

A DMA transfer error can be generated by reading from or writing to a reserved address space. When a DMA

transfer error occurs during a DMA read or a write access, the faulty channel is automatically disabled through

a hardware clear of its EN bit in the corresponding channel configuration register (DMA_CCRx). The channel's

transfer error interrupt flag (TEIF) in the ISR register is set and an interrupt is generated if the transfer error

interrupt enable bit (TEIE) in the DMA_CCRx register is set.

3.7.2.6 Interrupts

An interrupt can be produced on a half-transfer, transfer complete or transfer error for each DMA channel.

Separate interrupt enable bits are available for flexibility.

Table 42. DMA interrupt requests

Interrupt event Event flag Enable control bit

Half-transfer HTIF HTIE

Transfer complete TCIF TCIE

Transfer error TEIF TEIE

3.7.2.7 DMA request mapping

The eight requests from the peripherals (SPI, I2Cx[1,2] and UART) are multiplexed before entering DMA with

the ADC request. For each channel, the choice between the peripheral and the ADC is done through the

DMA_CONFIG register.

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Figure 11. DMA request mapping in BlueNRG-2

3.7.3 DMA registers

DMA peripheral base address (DMA_BASE_ADDR) 0xA0000000.

Table 43. DMA registers

Address offset Name RW Reset Description

0x00 ISR R 0x00000000 DMA interrupt status register. Refer to the detailed description below.

0x04 IFCR W 0x00000000 DMA interrupt flag clear register. Refer to the detailed description below.

Table 44. DMA - ISR register description: address offset DMA_BASE_ADDR+0x00

Bit Field name Reset RW Description

0 GIF0 0x0 R

Channel 0 global interrupt flag. This bit is set by hardware. It is

cleared by software writing 1 to the corresponding bit in the IFCR

0: No TE, HT or TC event on channel 0.

1: A TE, HT or TC event occurred on channel 0.

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Bit Field name Reset RW Description

1 TCIF0 0x0 R

Channel 0 transfer complete flag. This bit is set by hardware. It is

cleared by software writing 1 to the corresponding bit in the IFCR

0: No transfer complete (TC) on channel 0.

1: A transfer complete (TC) occurred on channel 0.

2HTIF0 0x0 R

Channel 0 half transfer flag. This bit is set by hardware. It is

cleared by software writing 1 to the corresponding bit in the IFCR

0: No half transfer (HT) event on channel 0.

1: A half transfer (HT) event occurred on channel 0.

3TEIF0 0x0 R

Channel 0 transfer error flag. This bit is set by hardware. It is

cleared by software writing 1 to the corresponding bit in the IFCR

0: No transfer error (TE) event on channel 0.

1: A transfer error (TE) occurred on channel 0.

4 GIF1 0x0 R

Channel 1 global interrupt flag. This bit is set by hardware. It is

cleared by software writing 1 to the corresponding bit in the IFCR

0: No TE, HT or TC event on channel 1.

1: A TE, HT or TC event occurred on channel 1.

5TCIF1 0x0 R

Channel 1 transfer complete flag. This bit is set by hardware. It is

cleared by software writing 1 to the corresponding bit in the IFCR

0: No transfer complete (TC) on channel 1.

1: A transfer complete (TC) occurred on channel 1.

6HTIF1 0x0 R

Channel 1 half transfer flag. This bit is set by hardware. It is

cleared by software writing 1 to the corresponding bit in the IFCR

0: No half transfer (HT) event on channel 1.

1: A half transfer (HT) event occurred on channel 1.

7TEIF1 0x0 R

Channel 1 transfer error flag. This bit is set by hardware. It is

cleared by software writing 1 to the corresponding bit in the IFCR

0: No transfer error (TE) event on channel 1.

1: A transfer error (TE) occurred on channel 1.

8 GIF2 0x0 R

Channel 2 global interrupt flag. This bit is set by hardware. It is

cleared by software writing 1 to the corresponding bit in the IFCR

0: No TE, HT or TC event on channel 2.

1: A TE, HT or TC event occurred on channel 2.

9TCIF2 0x0 R

Channel 2 transfer complete flag. This bit is set by hardware. It is

cleared by software writing 1 to the corresponding bit in the IFCR

0: No transfer complete (TC) on channel 2.

1: A transfer complete (TC) occurred on channel 2.

10 HTIF2 0x0 R

Channel 2 half transfer flag. This bit is set by hardware. It is

cleared by software writing 1 to the corresponding bit in the IFCR

0: No half transfer (HT) event on channel 2.

1: A half transfer (HT) event occurred on channel 2.

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Bit Field name Reset RW Description

11 TEIF2 0x0 R

Channel 2 transfer error flag. This bit is set by hardware. It is

cleared by software writing 1 to the corresponding bit in the IFCR

0: No transfer error (TE) event on channel 2.

1: A transfer error (TE) occurred on channel 2.

12 GIF3 0x0 R

Channel 3 global interrupt flag. This bit is set by hardware. It is

cleared by software writing 1 to the corresponding bit in the IFCR

0: No TE, HT or TC event on channel 3.

1: A TE, HT or TC event occurred on channel 3.

13 TCIF3 0x0 R

Channel 3 transfer complete flag. This bit is set by hardware. It is

cleared by software writing 1 to the corresponding bit in the IFCR

0: No transfer complete (TC) on channel 3.

1: A transfer complete (TC) occurred on channel 3.

14 HTIF3 0x0 R

Channel 3 half transfer flag. This bit is set by hardware. It is

cleared by software writing 1 to the corresponding bit in the IFCR

0: No half transfer (HT) event on channel 3.

1: A half transfer (HT) event occurred on channel 3.

15 TEIF3 0x0 R

Channel 3 transfer error flag. This bit is set by hardware. It is

cleared by software writing 1 to the corresponding bit in the IFCR

0: No transfer error (TE) event on channel 3.

1: A transfer error (TE) occurred on channel 3.

16 GIF4 0x0 R

Channel 4 global interrupt flag. This bit is set by hardware. It is

cleared by software writing 1 to the corresponding bit in the IFCR

0: No TE, HT or TC event on channel 4.

1: A TE, HT or TC event occurred on channel 4.

17 TCIF4 0x0 R

Channel 4 transfer complete flag. This bit is set by hardware. It is

cleared by software writing 1 to the corresponding bit in the IFCR

0: No transfer complete (TC) on channel 4.

1: A transfer complete (TC) occurred on channel 4.

18 HTIF4 0x0 R

Channel 4 half transfer flag. This bit is set by hardware. It is

cleared by software writing 1 to the corresponding bit in the IFCR

0: No half transfer (HT) event on channel 4.

1: A half transfer (HT) event occurred on channel 4.

19 TEIF4 0x0 R

Channel 4 transfer error flag. This bit is set by hardware. It is

cleared by software writing 1 to the corresponding bit in the IFCR

0: No transfer error (TE) event on channel 4.

1: A transfer error (TE) occurred on channel 4.

20 GIF5 0x0 R

Channel 5 global interrupt flag. This bit is set by hardware. It is

cleared by software writing 1 to the corresponding bit in the IFCR

0: No TE, HT or TC event on channel 5.

1: A TE, HT or TC event occurred on channel 5.

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Bit Field name Reset RW Description

21 TCIF5 0x0 R

Channel 5 transfer complete flag. This bit is set by hardware. It is

cleared by software writing 1 to the corresponding bit in the IFCR

0: No transfer complete (TC) on channel 5.

1: A transfer complete (TC) occurred on channel 5.

22 HTIF5 0x0 R

Channel 5 half transfer flag. This bit is set by hardware. It is

cleared by software writing 1 to the corresponding bit in the IFCR

0: No half transfer (HT) event on channel 5.

1: A half transfer (HT) event occurred on channel 5.

23 TEIF5 0x0 R

Channel 5 transfer error flag. This bit is set by hardware. It is

cleared by software writing 1 to the corresponding bit in the IFCR

0: No transfer error (TE) event on channel 5.

1: A transfer error (TE) occurred on channel 5.

24 GIF6 0x0 R

Channel 6 global interrupt flag. This bit is set by hardware. It is

cleared by software writing 1 to the corresponding bit in the IFCR

0: No TE, HT or TC event on channel 6.

1: A TE, HT or TC event occurred on channel 6.

25 TCIF6 0x0 R

Channel 6 transfer complete flag. This bit is set by hardware. It is

cleared by software writing 1 to the corresponding bit in the IFCR

0: No transfer complete (TC) on channel 6.

1: A transfer complete (TC) occurred on channel 6.

26 HTIF6 0x0 R

Channel 6 half transfer flag. This bit is set by hardware. It is

cleared by software writing 1 to the corresponding bit in the IFCR

0: No half transfer (HT) event on channel 6.

1: A half transfer (HT) event occurred on channel 6.

27 TEIF6 0x0 R

Channel 6 transfer error flag. This bit is set by hardware. It is

cleared by software writing 1 to the corresponding bit in the IFCR

0: No transfer error (TE) event on channel 6.

1: A transfer error (TE) occurred on channel 6.

28 GIF7 0x0 R

Channel 7 global interrupt flag. This bit is set by hardware. It is

cleared by software writing 1 to the corresponding bit in the IFCR

0: No TE, HT or TC event on channel 7.

1: A TE, HT or TC event occurred on channel 7.

29 TCIF7 0x0 R

Channel 7 transfer complete flag. This bit is set by hardware. It is

cleared by software writing 1 to the corresponding bit in the IFCR

0: No transfer complete (TC) on channel 7.

1: A transfer complete (TC) occurred on channel 7.

30 HTIF7 0x0 R

Channel 7 half transfer flag. This bit is set by hardware. It is

cleared by software writing 1 to the corresponding bit in the IFCR

0: No half transfer (HT) event on channel 7.

1: A half transfer (HT) event occurred on channel 7.

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Bit Field name Reset RW Description

31 TEIF7 0x0 R

Channel 7 transfer error flag. This bit is set by hardware. It is

cleared by software writing 1 to the corresponding bit in the IFCR

0: No transfer error (TE) event on channel 7.

1: A transfer error (TE) occurred on channel 7.

Table 45. DMA - IFCR register description: address offset DMA_BASE_ADDR+0x04

Bit Field name Reset RW Description

0 CGIF0 0x0 W

Channel 0 global interrupt flag. This bit is set by software.

0: No effect.

1: Clears the GIF, TEIF, HTIF and TCIF flags in the ISR register.

1 CTCIF0 0x0 W

Channel 0 transfer complete flag. This bit is set by software.

0: No effect.

1: Clears the corresponding TCIF flag in the ISR register.

2 CHTIF0 0x0 W

Channel 0 half transfer flag. This bit is set by software.

0: No effect.

1: Clears the corresponding HTIF flag in the ISR register.

3 CTEIF0 0x0 W

Channel 0 transfer error flag. This bit is set by software.

0: No effect.

1: Clears the corresponding TEIF flag in the ISR register.

4 CGIF1 0x0 W

Channel 1 global interrupt flag. This bit is set by software.

0: No effect.

1: Clears the GIF, TEIF, HTIF and TCIF flags in the ISR register.

5 CTCIF1 0x0 W

Channel 1 transfer complete flag. This bit is set by software.

0: No effect.

1: Clears the corresponding TCIF flag in the ISR register.

6 CHTIF1 0x0 W

Channel 1 half transfer flag. This bit is set by software.

0: No effect.

1: Clears the corresponding HTIF flag in the ISR register.

7 CTEIF1 0x0 W

Channel 1 transfer error flag. This bit is set by software.

0: No effect.

1: Clears the corresponding TEIF flag in the ISR register.

8 CGIF2 0x0 W

Channel 2 global interrupt flag. This bit is set by software.

0: No effect.

1: Clears the GIF, TEIF, HTIF and TCIF flags in the ISR register.

9 CTCIF2 0x0 W

Channel 2 transfer complete flag. This bit is set by software.

0: No effect.

1: Clears the corresponding TCIF flag in the ISR register.

10 CHTIF2 0x0 W

Channel 2 half transfer flag. This bit is set by software.

0: No effect.

1: Clears the corresponding HTIF flag in the ISR register.

11 CTEIF2 0x0 W Channel 2 transfer error flag. This bit is set by software.

0: No effect.

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Bit Field name Reset RW Description

1: Clears the corresponding TEIF flag in the ISR register.

12 CGIF3 0x0 W

Channel 3 global interrupt flag. This bit is set by software.

0: No effect.

1: Clears the GIF, TEIF, HTIF and TCIF flags in the ISR register.

13 CTCIF3 0x0 W

Channel 3 transfer complete flag. This bit is set by software.

0: No effect.

1: Clears the corresponding TCIF flag in the ISR register.

14 CHTIF3 0x0 W

Channel 3 half transfer flag. This bit is set by software.

0: No effect.

1: Clears the corresponding HTIF flag in the ISR register.

15 CTEIF3 0x0 W

Channel 3 transfer error flag. This bit is set by software.

0: No effect.

1: Clears the corresponding TEIF flag in the ISR register.

16 CGIF4 0x0 W

Channel 4 global interrupt flag. This bit is set by software.

0: No effect.

1: Clears the GIF, TEIF, HTIF and TCIF flags in the ISR register.

17 CTCIF4 0x0 W

Channel 4 transfer complete flag. This bit is set by software.

0: No effect.

1: Clears the corresponding TCIF flag in the ISR register.

18 CHTIF4 0x0 W

Channel 4 half transfer flag. This bit is set by software.

0: No effect.

1: Clears the corresponding HTIF flag in the ISR register.

19 CTEIF4 0x0 W

Channel 4 transfer error flag. This bit is set by software.

0: No effect.

1: Clears the corresponding TEIF flag in the ISR register.

20 CGIF5 0x0 W

Channel 5 global interrupt flag. This bit is set by software.

0: No effect.

1: Clears the GIF, TEIF, HTIF and TCIF flags in the ISR register.

21 CTCIF5 0x0 W

Channel 5 transfer complete flag. This bit is set by software.

0: No effect.

1: Clears the corresponding TCIF flag in the ISR register.

22 CHTIF5 0x0 W

Channel 5 half transfer flag. This bit is set by software.

0: No effect.

1: Clears the corresponding HTIF flag in the ISR register.

23 CTEIF5 0x0 W

Channel 5 transfer error flag. This bit is set by software.

0: No effect.

1: Clears the corresponding TEIF flag in the ISR register.

24 CGIF6 0x0 W

Channel 6 global interrupt flag. This bit is set by software.

0: No effect.

1: Clears the GIF, TEIF, HTIF and TCIF flags in the ISR register.

25 CTCIF6 0x0 W

Channel 6 transfer complete flag. This bit is set by software.

0: No effect.

1: Clears the corresponding TCIF flag in the ISR register.

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Bit Field name Reset RW Description

26 CHTIF6 0x0 W

Channel 6 half transfer flag. This bit is set by software.

0: No effect.

1: Clears the corresponding HTIF flag in the ISR register.

27 CTEIF6 0x0 W

Channel 6 transfer error flag. This bit is set by software.

0: No effect.

1: Clears the corresponding TEIF flag in the ISR register.

28 CGIF7 0x0 W

Channel 7 global interrupt flag. This bit is set by software.

0: No effect.

1: Clears the GIF, TEIF, HTIF and TCIF flags in the ISR register.

29 CTCIF7 0x0 W

Channel 7 transfer complete flag. This bit is set by software.

0: No effect.

1: Clears the corresponding TCIF flag in the ISR register.

30 CHTIF7 0x0 W

Channel 7 half transfer flag. This bit is set by software.

0: No effect.

1: Clears the corresponding HTIF flag in the ISR register.

31 CTEIF7 0x0 W

Channel 7 transfer error flag. This bit is set by software.

0: No effect.

1: Clears the corresponding TEIF flag in the ISR register.

• DMA_CH0 peripheral base address (DMA_CH0_BASE_ADDR) 0xA0000008

• DMA_CH1 peripheral base address (DMA_CH1_BASE_ADDR) 0xA000001C

•DMA_CH2 peripheral base address (DMA_CH2_BASE_ADDR) 0xA0000030

• DMA_CH3 peripheral base address (DMA_CH3_BASE_ADDR) 0xA0000044

• DMA_CH4 peripheral base address (DMA_CH4_BASE_ADDR) 0xA0000058

• DMA_CH5 peripheral base address (DMA_CH5_BASE_ADDR) 0xA000006C

• DMA_CH6 peripheral base address (DMA_CH6_BASE_ADDR) 0xA0000080

• DMA_CH7 peripheral base address (DMA_CH7_BASE_ADDR) 0xA0000094

Table 46. DMA_CHx registers

Address offset Name RW Reset Description

0x00 CCR RW 0x00000000 DMA channel configuration register. Refer to the detailed description

below.

0x04 CNDTR RW 0x00000000 DMA channel number of data register. Refer to the detailed description

below.

0x08 CPAR RW 0x00000000 DMA channel peripheral address register. Refer to the detailed

description below.

0x0C CMAR RW 0x00000000 DMA channel memory address register. Refer to the detailed

description below.

Table 47. DMA_CHx - CCR register description: address offset DMA_CHX_BASE_ADDR+0x00

Bit Field name Reset RW Description

0 EN 0x0 RW

DMA channel enable.

0: DMA channel disabled.

1: DMA channel enabled.

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Bit Field name Reset RW Description

1 TCIE 0x0 RW

Transfer complete interrupt enable.

0: TC interrupt disabled.

1: TC interrupt enabled.

2 HTIE 0x0 RW

Half transfer interrupt enable.

0: HT interrupt disabled.

1: HT interrupt enabled.

3 TEIE 0x0 RW

Transfer error interrupt enable.

0: TE interrupt disabled.

1: TE interrupt enabled.

4 DIR 0x0 RW

Data transfer direction.

0: Read from peripheral.

1: Read from memory.

5 CIRC 0x0 RW

Circular mode.

0: Circular mode disabled.

1: Circular mode enabled.

6 PINC 0x0 RW

Peripheral increment mode.

0: Peripheral increment disabled.

1: Peripheral increment enabled.

7 MINC 0x0 RW

Memory increment mode.

0: Memory increment disabled.

1: Memory increment enabled.

9:8 PSIZE 0x0 RW

Peripheral size.

00b: Size 8 bits.

01b: Size 16 bits.

10b: Size 32 bits.

11:10 MSIZE 0x0 RW

Memory size.

00b: Size 8 bits.

01b: Size 16 bits.

10b: Size 32 bits.

13:12 PL 0x0 RW

Channel priority level.

00b: Low priority.

01b: Medium priority.

10b: High priority.

11b: Very high priority.

14 MEM2MEM 0x0 RW

Memory-to-memory mode.

0: Memory-to-memory mode disabled.

0: Memory-to-memory mode enabled.

31:15 RESERVED 0x0 RW RESERVED

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Table 48. DMA_CHx - CNDTR register description: address offset DMA_CHX_BASE_ADDR+0x04

Bit Field name Reset RW Description

15:0 NDT 0x0 RW

Number of data to be transferred (0 up to 65535). This register can

only be written when the channel is disabled. Once the channel is

enabled, this register is read-only, indicating the remaining bytes to

be transmitted. This register decrements after each DMA transfer.

Once the transfer is completed, this register can either stay at zero

or be reloaded automatically by the value previously programmed

if the channel is configured in auto-reload mode. If this register is

zero, no transaction can be served whether the channel is enabled

or not.

31:16 RESERVED 0x0 RW RESERVED

Table 49. DMA_CHx - CPAR register description: address offset DMA_CHX_BASE_ADDR+0x08

Bit Field name Reset RW Description

31:0 PA 0x0 RW

Base address of the peripheral data register from/to which the data

are read/written. When PSIZE is 01 (16-bit), the PA[0] bit is ignored.

Access is automatically aligned to a halfword address. When

PSIZE is 10 (32-bit), PA[1:0] are ignored. Access is automatically

aligned to a word address.

Table 50. DMA_CHx - CMAR register description: address offset DMA_CHX_BASE_ADDR+0x0C

Bit Field name Reset RW Description

31:0 MA 0x0 RW

Base address of the memory area from/to which the data are read/

written. When MSIZE is 01 (16-bit), the MA[0] bit is ignored. Access

is automatically aligned to a halfword address. When MSIZE is 10

(32-bit), MA[1:0] are ignored. Access is automatically aligned to a

word address.

Note: All RESERVED fields inside registers must always be written with their default values.

3.8 SPI

3.8.1 Introduction

The BlueNRG-2 integrates a serial peripheral interface compatible with the Motorola and National Semiconductor

Microwire standards.

Main features are:

•Maximal supported baud rate is 1 MHz in slave mode and 8 MHz in master mode.

•Parallel-to-serial conversion on data written to an internal 32-bit wide, 16-location deep transmitter FIFO.

• Serial-to-parallel conversion on received data, buffering in a 32-bit wide 16-location deep receive FIFO.

• Programmable data frame size from 4-bit to 32-bit.

• Programmable clock bit rate and prescaler.

• Programmable clock phase and polarity in SPI mode.

• Support for direct memory access (DMA).

3.8.2 Functional overview

The SPI performs serial-to-parallel conversion on data received from a peripheral device on the SPI_IN pin, and

parallel-to-serial conversion on data written by CPU for transmission on the SPI_OUT pin.

The role of the SPI pins are defined by the SPI master or SPI slave role.

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Table 51. SPI pin assignments

SPI role SPI_IN pin SPI_OUT pin

Master MISO MOSI

Slave MOSI MISO

The transmit and receive paths are buffered with internal FIFO memories allowing up to 16 x 32-bit values to be

stored independently in both transmit and receive modes. FIFOs may be burst-loaded or emptied by the system

processor or by the DMA, from one to eight words per transfer. Each 32-bit word from the system fills one entry in

FIFO.

The SPI includes a programmable bitrate clock divider and prescaler to generate the serial output clock signal

from the SPI_CLK pin.

3.8.2.1 SPI clock phase and clock polarity

The SPH control bit selects the clock edge that captures data and allows it to change state. It has the most impact

on the first bit transmitted by either allowing or not allowing a clock transition before the first data capture edge.

The SPO bit selects the clock polarity (low or high) of the clock signal. SPH in conjunction with the SPO bit allow

four possible timing variations listed in the following table.

Table 52. SPI clock phase and clock polarity

SPH SPO Timing description

0b 0b

The clock signal is stopped to low inactive level between transfers. The first rising edge occurs in the middle of

the first data bit (with delay). The SPI transmits data one-half cycle ahead of the rising edge of clock signal and

receives data on the rising edge of clock signal. In case of multi byte transmission, the CS line must be pulsed

HIGH between each data word transfer.

0b 1b

The clock signal is stopped to high inactive level between transfers. The first falling edge occurs in the middle of

the first data bit (with delay). The SPI transmits data one-half cycle ahead of the falling edge of clock signal and

receives data on the falling edge of clock signal. In case of multi byte transmission, the CS line must be pulsed

HIGH between each data word transfer.

1b 0b

The clock signal is stopped to low inactive level between transfers. The first rising edge occurs at the start of the

first data bit (no delay). The SPI transmits data on the rising edge of clock signal and receives data on the failing

edge of clock signal.

1b 1b

The clock signal is stopped to high inactive level between transfers. The first falling edge occurs at the start of the

first data bit (no delay). The SPI transmits data on the falling edge of clock signal and receives data on the rising

edge of clock signal.

3.8.2.2 Procedure for enabling SPI

The SPI initialization procedure is the following (assuming clocks already enabled):

1. Clear the SSE bit in the CR1 register. This step is not required after a hardware or software reset of the

BlueNRG-2.

2. Empty the receive FIFO. This step is not required after a hardware or software reset of the device

BlueNRG-2.

3. Program IO_MODE to route SPI port signals on those GPIOs. See section GPIO operating modes.

4. Program the SPI clock prescaler register (CPSR), then program the configuration registers CR0 and CR1.

5. The transmit FIFO can optionally be filled before enabling the SPI.

6. Set the SSE bit to enable SPI operation.

Note: The transmit FIFO and the receive FIFO are not cleared when the SSE bit is cleared.

3.8.2.3 SPI bit rate generation

The SPI bitrate is derived by dividing down the peripheral clock (CLK) by an even prescaler value CPSDVSR from

2 to 254, the clock is further divided by a value from 1 to 256, which is 1+SCR. The SPI frequency clock duty

cycle is always 0.5.

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3.8.2.4 SPI data endianness

All transfers can be sent and received with configurable endianness according the setting of the (T/R)ENDN bit in

the CR1 registers

The cases "00b" and "11b" of TENDN and RENDN are implemented for data frame size from 4- to 32-bit. The

cases "01b" and "10b" of TENDN and RENDN are implemented only for the following data frame sizes: 16-bit,

24-bit and 32-bit. Transmit data endianness: TENDN in CR1:

Table 53. SPI_OUT endianness

TENDN Endianness

00b The element is transmitted MSByte-first and MSbit-first.

01b The element is transmitted LSByte-first and MSbit-first.

10b The element is transmitted MSByte-first and LSbit-first.

11b The element is transmitted LSByte-first and LSbit-first.

Table 54. SPI_IN endianness

RENDN Endianness

00b The element is received MSByte-first and MSbit-first.

01b The element is received LSByte-first and MSbit-first.

10b The element is received MSByte-first and LSbit-first.

11b The element is received LSByte-first and LSbit-first.

3.8.2.5 SPI interrupts

There are six individual maskable interrupt sources generated by the SPI (single interrupt signal that drives the

NVIC):

•Receive interrupt

•Transmit interrupt

• Timeout interrupt

• Receive overrun interrupt

• Transmit underrun interrupt

• Transmit empty interrupt

The user can enable or disable the individual interrupt sources by changing the mask bits in the IMSC register.

Setting the appropriate mask bit to 1b enables the interrupt. The status of the individual interrupt sources can be

read from the RIS register (raw interrupt status) or from the MIS register (masked interrupt status).

3.8.2.6 Receive interrupt

The receive interrupt is asserted when the number of data in receive FIFO reaches the programmed trigger

watermark level. The receive interrupt is cleared by reading data from the receive FIFO until there are less data

than the programmed watermark level.

3.8.2.7 Transmit interrupt

The transmit interrupt is asserted when the number of data in the transmit FIFO is less than or equal to the

programmed watermark level. It is cleared by performing writes to the transmit FIFO until it holds more elements

than the programmed watermark level. The transmitter interrupt is not qualified with the SPI enable bit, which

allows operation in one of two ways:

•Data can be written to the transmit FIFO prior to enabling the SPI and the interrupts.

•Or the SPI and the interrupts can be enabled so that data can be written to the transmit FIFO by an interrupt

service routine.

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3.8.2.8 Timeout interrupt

The receive timeout interrupt is asserted when the receive FIFO is not empty, and no further data is received over

a 32-bit period of the serial clock. This mechanism ensures that the user is aware that data is still present in the

receive FIFO and requires servicing.

The receive timeout interrupt is cleared either when the FIFO becomes empty through reading all the data, or if

new data is received, or when a 1b is written to the corresponding bit of the ICR register.

3.8.2.9 Receive overrun interrupt

The receive overrun interrupt is asserted when the receive FIFO is already full and an additional data frame is

received, causing an overrun of the FIFO. Data is overwritten in the receive shift register, but not in the FIFO. The

interrupt is cleared when a 1b is written to the corresponding bit of the ICR register.

3.8.2.10 Transmit underrun interrupt

The transmit underrun interrupt is asserted when the transmit FIFO is already empty and an additional frame is

transmitted, causing an underrun of the FIFO. Data is over-read in the transmit shift register. This interrupt is

cleared when a 1b is written to the corresponding bit of the ICR register.

3.8.2.11Transmit empty interrupt

The transmit interrupt is asserted when the transmit FIFO is empty. It is cleared by performing writes to the

transmit FIFO.

3.8.2.12 SPI master communication mode for Motorola standard

The SPIM register field selects the SPI transmission mode, these modes are applicable only for SPI master

mode:

• Full duplex mode (SPIM = 00b): the master transmits the data available in the TXFIFO and receives the data

from the slave.

•Transmit mode (SPIM = 01b): when the data is available in TX FIFO, the SPI_OUT line is run, and no data is

written in RX FIFO

• Receive mode (SPIM = 10b): the sequence of receive mode is:

1. The software sets the mode to receive (SPIM = 10) and writes the dummy character value to the CHN

2. The software writes the value “number of frames to receive from the slave” in the RXFRM register.

When the receive mode is selected we have two cases:

1. If the TXFIFO is empty, the master receives data from the slave, transmitting the character from

the CHN register in each frame received. The RXFRM register is decremented by one at each

transmission/reception. The interface runs until the RXFRM value is dummy AND the written number of

frames in RXFRM is received.

2. If the TXFIFO is not empty, the master first transmits the data available in the TXFIFO and receives

the data from the slave (like the full duplex mode). The RXFRM register is not decremented. When all

the data available in TXFIFO are transmitted, the TXFIFO becomes empty (case a), then the dummy

character from the CHN register are transmitted for each frame received. The RXFRM register is

decremented for each transaction. When the value in this register is zero and the written number of

frames in RXFRM is received, the interface does not run anymore. The user has to write the RXFRM

(with value greater than zero) by software to reactivate the interface.

Note: In all cases, the RXFRM is decremented by one only if the TXFIFO is empty. The RFRM is decremented before

the data is sent.

Note: If the software fills the TXFIFO while the SPI is transmitting the dummy character, then the words of TXFIFO

should be ignored and we should not send them in this mode, only the dummy -character are transmitted.

• Combined mode (SPIM = 11b): the sequence of combined mode is:

1. The software sets the mode to combined mode: (SPIM=11).

2. The software writes to the WDTXF register the "number of frames to be received by the slave (a value

greater than zero) from TXFIFO master".

If the number of words written in the WDTXF register are sent (WDTXF is equal to zero) but the RXFRM register

is not equal to zero, the master transmits the dummy character (defined in CHM register) and receives the slave

data, decrementing the RXFRM register by one. Once the RXFRM register is equal to zero and all the data

written in RXFRM are sent, the interface is stopped.

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When the RXFRM register is zero and WDTXF is not equal to zero and the TXFIFO of the master and of slave

are not empty, the master transmits the data from TXFIFO and receives the data from the slave. Before the data

is sent from TXFIFO, the WDTXF is decremented by one. When the WDTXF register is zero and all the numbers

written in this register are sent, the interface is stopped.

The interface is stopped when:

•WDTXF and RXFRM registers are equal to zero.

• WDTXF register is not equal to zero and TXFIFO is empty.

• RXFRM register is not equal to zero, the WDTXF register is zero and TXFIFO is not empty.

For each data transmission (TXFIFO data or CHN register data), the data slave is received.

WDTXF is decremented by one only at each data transmission from TXFIFO. The decrementing is done before

the words are sent out.

RXFRM is decremented by one only at each dummy character transmission from the CHN register. The

decrementing is done before the words are sent out.

When we start decrementing one of the registers (RXFRM or WDTXF), we must decrement until we reach zero

and we send the last words before starting the decrement of other registers (RXFRM or WDTXF).

Switching between these different modes when SPI is enabled is possible. If the transmission mode is deselected

for another mode during a frame transmission, the new mode becomes active at the start of the next word.

3.8.2.13 SPI master communication mode for National Semiconductor Microwire standard

The FRF register field selects the SPI mode interface: the default value 0 indicates the Motorola standard

interface, while FRF = 2 selects the Microwire standard interface for the 3-wire SPI mode.

The hardware connection considers the SPI_IN and SPI_OUT pins connected together as shown in the figure

below. The two pins are handled internally to send and receive data.

Figure 12. MicroWire master and slave communication

The CSS register field specifies the length of the data to send and the DSS register field specifies the length of

the data to receive.

In reception mode, the quantity of data to read is specified in the DSS register field. The set of the SSE register

field, enables SPI for the communication. The user should wait for data reception to end before attempting any

reads. The SSE register field must be reset at the end of the communication.

In transmission mode, the send data are written inside the TX FIFO and the quantity of data to send is specified

in the CSS register field. The SSE register field setting enables SPI for the communication. When the busy flag is

RESET, SPI communication is terminated. The SSE register field must be reset at the end of the communication.

3.8.3 SPI registers

SPI peripheral base address (SPI_BASE_ADDR) 0x40400000.

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Table 55. SPI registers

Address offset Name RW Reset Description

0x00 CR0 RW 0x1C000000 Control register 0. Refer to the detailed description below.

0x04 CR1 RW 0x00000000 Control register 1. Refer to the detailed description below.

0x08 DR RW 0x00000000 Data register. Refer to the detailed description below.

0x0C SR R 0x00000003 Status register. Refer to the detailed description below.

0x10 CPSR RW 0x00000000 Clock prescale register. Refer to the detailed description below.

0x14 IMSC RW 0x00000000 Interrupt mask set or clear register. Refer to the detailed description below.

0x18 RIS R 0x00000000 Raw interrupt status register. Refer to the detailed description below.

0x1C MIS R 0x00000000 Masked interrupt status register. Refer to the detailed description below.

0x20 ICR W 0x00000000 Interrupt clear register. Refer to the detailed description below.

0x24 DMACR RW 0x00000000 SPI DMA control register. Refer to the detailed description below.

0x28 RXFRM RW 0x00000000 SPI receive frame register. Indicates the number of frames to receive from

the slave.

0x2C CHN RW 0x00000000 Dummy character register

0x30 WDTXF RW 0x00000000 SPI transmit FIFO receive frame number. Indicates the number of frames to

receive from the transmit FIFO

0x80 ITCR RW 0x00000000 Integration test control register. Refer to the detailed description below.

0x8C TDR RW 0x00000000 Test data register

Table 56. SPI - CR0 register description: address offset SPI_BASE_ADDR+0x00

Bit Field name Reset RW Description

4:0 DSS 0x0 RW

Data size select. (DSS+1) defines the number of bits:

0x00: Reserved.

0x01: Reserved.

0x02: Reserved.

0x03: 4-bit data.

0x04: 5-bit data.

...

0x1F: 32-bit data.

5 RESERVED 0x0 RW RESERVED

6 SPO 0x0 RW

Clock polarity (Motorola SPI format only):

0: Steady-state of clock polarity is low.

1: Steady-state of clock polarity is high.

7SPH 0x0 RW

Clock phase (Motorola SPI format only):

0: Steady-state of clock phase is low.

1: Steady-state of clock phase is high.

15:8 SCR 0x0 RW

Serial clock rate.

The SRC value is used to generate the transmit and receive bit rate of the

SPI. The bit rate is: f_SPICLK / (CPSDVR * (1 + SCR)), where CPSDVR is

an even value from 2 to 254 and SCR is a value from 0 to 255.

20:16 CSS 0X00 RW

Command size select (CSS+1) defines the number of bits for the command

in MicroWire mode only:

0x00: Reserved

0x01: Reserved

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Bit Field name Reset RW Description

0x02: Reserved

0x03: 4-bit data

0x04: 5-bit data

...

0x1F: 32-bit data

21:22 FRF 0x00 RW

Frame format:

0: Motorola SPI frame format

2: National MicroWire frame format

24:23 SPIM 0x0 RW

SPI master transmission mode (in Motorola SPI master mode only):

00b: Full duplex mode.

01b: Transmit mode.

10b: Receive mode.

11b: Combined mode.

25 RESERVED 0x0 RW RESERVED

26 CS1 0x1 RW

Chip selection for slave one

0: the slave 1 is selected.

1: the slave 1 is not selected.

31:27 RESERVED 0x3 RW RESERVED

Table 57. SPI - CR1 register description: address offset SPI_BASE_ADDR+0x04

Bit Field name Reset RW Description

0 RESERVED 0x0 RW RESERVED

1 SSE 0x0 RW

SPI enable.

0: SPI disable.

1: SPI enable.

2 MS 0x0 RW

Master or slave mode select.

0: Master mode.

1: Slave mode.

3 SOD 0x0 RW

Slave mode output disable (slave mode only).

0: SPI can drive the MISO signal in slave mode.

1: SPI must not drive the MISO signal in slave mode.

In multiple slave system, it is possible for a SPI master to broadcast a

message to all slaves in the system while ensuring only one slave drives

data onto the serial output line MISO.

5:4 RENDN 0x0 RW

Receive endian format.

00b: The element is received MSByte-first and MSbit-first.

01b: The element is received LSByte-first and MSbit-first.

10b: The element is received MSByte-first and LSbit-first.

11b: The element is received LSByte-first and LSbit-first.

The cases 00b and 11b are set for data frame size from 4 to 32 bits. The

cases 01b and 10b are set only for data frame size 16, 24 and 32 bits.

6 MWAIT 0x0 RW

MicroWire wait state bit enable:

0: No wait state

1: One wait state

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Bit Field name Reset RW Description

9:7 RXIFLSEL 0x0 RW

Receive interrupt FIFO level select. This bit field selects the trigger points to

receive FIFO interrupt:

000b: RX FIFO contains 1 element or more.

001b: RX FIFO contains 4 elements or more.

010b: RX FIFO contains 8 elements or more.

Others: Reserved.

12:10 TXIFLSEL 0x0 RW

Transmit interrupt FIFO level select. This bit field selects the trigger points to

transmit FIFO interrupt:

000b: TX FIFO contains 1 element or more.

001b: TX FIFO contains 4 elements or more.

010b: TX FIFO contains 8 elements or more.

Others: Reserved.

13 RESERVED 0x0 RW RESERVED

17:14 MSPIWAIT 0x0 RW Motorola SPI wait mode. This value is used to insert a wait state between

frames.

19:18 TENDN 0x0 RW

Transmit endian format.

00b: The element is transmitted MSByte-first and MSbit-first.

01b: The element is transmitted LSByte-first and MSbit-first.

10b: The element is transmitted MSByte-first and LSbit-first.

11b: The element is transmitted LSByte-first and LSbit-first.

The cases 00b and 11b are set for data frame size from 4 to 32 bits. The

cases 01b and 10b are set only for data frame size 16, 24 and 32 bits.

20 RESERVED 0x0 RW RESERVED

21 DATAINDEL 0x0 RW

Data input delay.

0: No delay is inserted in data input.

1: A delay of 2-clock cycles is inserted in the data input path.

31:22 RESERVED 0x0 RW RESERVED

Table 58. SPI - DR register description: address offset SPI_BASE_ADDR+0x08

Bit Field

name Reset RW Description

31:0 DATA 0x0 RW

Transmit/receive data:

Read: RX FIFO is read.

Write: TX FIFO is written.

Data must be right-justified when a data size of less than 32-bit is programmed.

Unused bits are ignored by the transmit logic. The receive logic automatically

right-justifies data.

Table 59. SPI - SR register description: address offset SPI_BASE_ADDR+0x0C

Bit Field name Reset RW Description

0 TFE 0x1 R

Transmit FIFO empty:

0: TX FIFO is not empty.

1: TX FIFO is empty.

1 TNF 0x1 R Transmit FIFO not full:

0: TX FIFO is full.

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Bit Field name Reset RW Description

1: TX FIFO is not full.

2 RNE 0x0 R

Receive FIFO not empty:

0: RX FIFO is empty.

1: RX FIFO is not empty.

3 RFF 0x0 R

Receive FIFO full:

0: RX FIFO is not full.

1: RX FIFO is full.

4 BSY 0x0 R

SPI busy flag:

0: SPI is idle.

1: SPI is currently transmitting and/or receiving a frame or the TX FIFO is not

empty.

31:5 RESERVED 0x0 R RESERVED

Table 60. SPI - CPSR register description: address offset SPI_BASE_ADDR+0x10

Bit Field name Reset RW Description

7:0 CPSDVSR 0x0 RW

Clock prescaler divisor. It must be an even number from 2 to 254. The value

is used to generate the transmit and receive bit rate of the SPI. The bit rate is:

FSSPCLK / [CPSDVR x (1+SCR)]

where SCR is a value from 0 to 255, programmed through the SSP_CR0

31:8 RESERVED 0x0 RW RESERVED

Table 61. SPI - IMSC register description. Address offset SPI_BASE_ADDR+0x14.

Bit Field name Reset RW Description

0 RORIM 0x0 RW

Receive overrun interrupt mask:

0: RX FIFO written to while full condition interrupt is masked (irq disabled).

1: RX FIFO written to while full condition interrupt is not masked (irq enabled).

1 RTIM 0x0 RW

Receive timeout interrupt mask:

0: RX FIFO not empty or no read prior to the timeout period interrupt is

masked (irq disabled).

1: RX FIFO not empty or no read prior to the timeout period interrupt is not

masked (irq enabled).

2 RXIM 0x0 RW

Receive FIFO interrupt mask:

0: Receive interrupt is masked (irq disabled).

1: Receive interrupt is not masked (irq enabled).

3 TXIM 0x0 RW

Transmit FIFO interrupt mask:

0: Transmit interrupt is masked (irq disabled).

1: Transmit interrupt is not masked (irq enabled).

4 TURIM 0x0 RW

Transmit underrun interrupt mask:

0: Transmit underrun interrupt is masked (irq disabled).

1: Transmit underrun interrupt is not masked (irq enabled).

5 TEIM 0x0 RW

Transmit FIFO empty interrupt mask:

0: TX FIFO empty interrupt is masked (irq disabled).

1: TX FIFO empty interrupt is not masked (irq enabled).

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Bit Field name Reset RW Description

31:6 RESERVED 0x0 RW RESERVED

Table 62. SPI - RIS register description: address offset SPI_BASE_ADDR+0x18

Bit Field name Reset RW Description

0 RORRIS 0x0 R Receive overrun raw interrupt status

1 RTRIS 0x0 R Receive time out raw interrupt status

2 RXRIS 0x0 R Receive raw interrupt status

3 TXRIS 0x0 R Transmit raw interrupt status

4 TURRIS 0x0 R Transmit underrun raw interrupt Status

5 TERIS 0x0 R Transmit FIFO empty raw interrupt status

31:6 RESERVED 0x0 R RESERVED

Table 63. SPI - MIS register description: address offset SPI_BASE_ADDR+0x1C

Bit Field name Reset RW Description

0 RORMIS 0x0 R Receive overrun masked interrupt status: gives the interrupt status after

masking of the receive overrun interrupt.

1 RTMIS 0x0 R Receive time out masked interrupt status: gives the interrupt status after

masking of receive timeout interrupt.

2 RXMIS 0x0 R Receive masked interrupt status: gives the interrupt status after masking of

the receive interrupt.

3 TXMIS 0x0 R Transmit masked interrupt status: gives the interrupt status after masking of

the transmit interrupt.

4 TURMIS 0x0 R Transmit underrun masked interrupt status: gives the interrupt status after

masking of the transmit underrun interrupt.

5 TEMIS 0x0 R Transmit FIFO empty masked interrupt status: gives the interrupt status after

masking of the transmit FIFO empty interrupt.

31:6 RESERVED 0x0 R RESERVED

Table 64. SPI - ICR register description: address offset SPI_BASE_ADDR+0x20

Bit Field name Reset RW Description

0 RORIC 0x0 W Receive overrun clear interrupt: writing 1 clears the receive overrun interrupt.

1 RTIC 0x0 W Receive time out clear interrupt: writing 1 clears the receive timeout interrupt.

2 TURIC 0x0 W Transmit underrun clear interrupt: writing 1 clears the transmit overrun

interrupt.

31:3 RESERVED 0x0 W RESERVED

Table 65. SPI - DMACR register description: address offset SPI_BASE_ADDR+0x24

Bit Field name Reset RW Description

0 RXDMASE 0x0 RW

Single receive DMA request.

0: Single transfer DMA in receive disable.

1: Single transfer DMA in receive enable.

1 RESERVED 0x0 RW RESERVED

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Bit Field name Reset RW Description

2 TXDMASE 0x0 RW

Single transmit DMA request.

0: Single transfer DMA in transmit disable.

1: Single transfer DMA in transmit enable.

31:3 RESERVED 0x0 RW RESERVED

Table 66. SPI – RXFRM register description: address offset SPI_BASE_ADDR+0x28

Bit Field name Reset RW Description

15:0 RXFRM 0x0000 RW SPI receive frame register. Indicates the number of frames to receive from the slave.

31:16 RESERVED 0x0000 RW RESERVED

Table 67. SPI – CHN register description: address offset SPI_BASE_ADDR+0x2C

Bit Field name Reset RW Description

31:0 CHN 0x00000000 RW Dummy character register.

Table 68. SPI – WDTXF register description: address offset SPI_BASE_ADDR + 0x30

Bit Field name Reset RW Description

15:0 WDTXF 0x0000 0x0000 SPI transmit FIFO receive frame number. Indicates the number of frames to receive

from the TX FIFO.

31:16 RESERVED 0x0000 0x0000 RESERVED

Table 69. SPI - ITCR register description: address offset SPI_BASE_ADDR+0x80

Bit Field name Reset RW Description

0 RESERVED 0x0 RW RESERVED

1 SWAPFIFO 0x0 RW

FIFO control mode:

0: FIFO normal mode. Write in TDR register puts data in TX FIFO and read

from TDR register read data from RX FIFO.

1: FIFO swapped mode. Write in TDR register puts data in RX FIFO and read

from TDR register read data from TX FIFO.

The registers SWAPFIFO and TDR allow the TX FIFO to be cleared from

unwanted data.

31:2 RESERVED 0x0 RW RESERVED

Table 70. SPI – TDR register description: address offset SPI_BASE_ADDR+0x8C

Bit Field name Reset RW Description

31:0 TDR 0x00000000 RW

Allows reading out data from TX FIFO if the SWAPFIFO bitfield is set.

The registers SWAPFIFO and TDR allow the TX FIFO to be cleared from unwanted

data.

Note: All RESERVED fields inside registers must always be written with their default values.

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3.9 UART

3.9.1 Introduction

The BlueNRG-2 integrates a universal asynchronous receiver/transmitter that support much of the functionality of

the industry-standard 16C650 UART.

Main features are:

• Programmable baud rates up to 2 Mbps.

• Programmable data frame of 5, 6, 7 or 8 bits of data.

• Even, odd, stick or no-parity bit generation and detection.

• Programmable 1 or 2 stop bit.

• Support of hardware flow control using CTS and RTS pins.

• Support of software flow control using programmable Xon/Xoff characters

• False start bit detection.

• Line break generation and detection.

• Programmable 8-bit wide, 64-deep transmit FIFO and 12-bit wide (8-bit data and 4-bit status) , 64-deep

receive FIFO.

• Support for direct memory access (DMA).

3.9.2 Functional description

The UART performs serial-to-parallel conversion on data asynchronously received from a peripheral device on

the UART_RX pin, and parallel-to-serial conversion on data written by CPU for transmission on the UART_TX

pin. The transmit and receive paths are buffered with internal FIFO memories allowing up to 64 data byte for

transmission, and 64 data byte with 4-bit status (break, frame, parity, and overrun) for receive. FIFOs may be

burst-loaded or emptied by the system processor from 1 to 16 words per transfer.

3.9.2.1 Data transmission or reception

Data received or transmitted is stored in two 64-byte FIFOs. The receive FIFO has an extra four bits per character

for the status information:

• Error bits 8 to 10 are associated with a particular character: break error, parity error and framing error.

• Overrun indicator bit 11 is set when the FIFO is full, and the next character is completely received in the

shift register. The data in the shift register is overwritten, but it is not written into the FIFO. When an empty

location is available in the receive FIFO, and another character is received, the state of the overrun bit is

copied into the received FIFO along with the received character. The overrun state is then cleared.

Table 71. RX FIFO errors

FIFO bit Function

11 Overrun indicator

10 Break error

9 Parity error

8 Framing error

7:0 Received data

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For transmission, data is written into the transmit FIFO. If the UART is enabled, it causes a data frame to start

transmitting with the parameters indicated in LCRH_TX. Data continue to be transmitted until there is no data

left in the transmit FIFO. The BUSY flag in the UARTFR register is set as soon as data is written to the transmit

FIFO (that is, the FIFO is non-empty) and remains asserted while data is being transmitted. BUSY is cleared only

when the transmit FIFO is empty, and the last character has been transmitted from the shift register, including

the stop bits. BUSY can be set even though the UART might no longer be enabled. For each sample of data,

three readings are taken and the majority value is kept. In the following paragraphs, the middle sampling point is

defined, and one sample is taken either side of it. When the receiver detect a start bit, the receive counter runs

and data is sampled on the 8th cycle of that counter in normal UART mode. The start bit is valid if UART_RX

signal is still low on the eighth cycle of Baud16, otherwise a false start bit is detected and it is ignored. If the start

bit is valid, successive data bits are sampled on every 16th cycle of Baud16 (that is 1-bit period later) according to

the programmed length of the data characters. The parity bit is then checked if parity mode was enabled. Lastly,

a valid stop bit is confirmed if UART_RX signal is high, otherwise a framing error has occurred. When a full word

is received, the data is stored in the receive FIFO, with any error bits associated with that. The UART character

frame is shown in Figure 13. UART character frame below.

Figure 13. UART character frame

The FIFOs can be disabled. In this case, the transmit and receive sides of the UART have 1-byte holding registers

(the bottom entry of the FIFOs). The overrun bit is set when a word has been received, and the previous one was

not yet read. In this implementation, the FIFOs are not physically disabled, but the flags are manipulated to give

the illusion of a 1-byte register.

3.9.2.2 Baud rate divisor

The baud rate divisor is a 22-bit number consisting of a 16-bit integer (BRDI) and a 6-bit fractional part (BRDF).

The fractional baud rate divider enables the use of any clock to act as UART_CLK, while it is still possible to

generate all the standard baud rates.

The 16-bit integer is loaded through the UART_IBRD register and the 6-bit fractional part is loaded into the

UART_FBRD register. The baud rate divisor has the following relationship:

When bit OVSFACT = 0b: divisor = UARTCLK/(16 x baud rate) = BRDI + BRDF.

When bit OVSFACT = 1b: divisor = UARTCLK/(8 x baud rate) = BRDI + BRDF.

Calculation of the fractional 6-bit number (DIVFRAC) is done by taking the fractional part of the required baud rate

divisor and multiplying it by 64 (that is, 2n, where n is the width of the UART_FBRD register) and adding 0.5 to

account for rounding errors:

DIVFRAC = integer(BRDF * 64 + 0.5)

The maximum deviation error using a 6-bit UART_FBRD register is 1/64 * 100 = 1.56%.

This occurs when DIVFRAC = 1, and the error is cumulative over 64 clock ticks.

Example 1: Calculating the divisor value (with OVSFACT = 0b).

If the required baud rate is 460 800 and the UART clock frequency is 16 MHz then:

Baud rate divisor = (16 x 106) / (16 x 460 800) = 2.170

BRDI = 2 and BRDF = 0.170

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Therefore fractional part DIVFRAC = integer(BRDF * 64 + 0.5) = 11

Generated baud rate divider = 2 + (11 / 64) = 2.171875

Generated baud rate = (16 x 106) / (16 x 2.171875) = 460 431

Error = (460 800 - 460 431) / 460 800 x 100 = 0.08%

An internal clock enable signal, Baudl6, is generated, and is a stream of one UARTCLK wide pulses with an

average frequency of 16 (OVSFACT = 0b) or 8 (OVSFACT = 1b) times the desired baud rate. This signal is then

divided by 16 or 8 to give the transmit clock. A low number in the baud rate divisor gives a short bit period, and a

high number in the baud rate divisor gives a long bit period.

Table 72. Typical baud rates with OVSFACT = 0 shows some typical bit rates and their corresponding divisors

when OVSFACT = 0b, given the UART clock frequency of 16 MHz.

Table 72. Typical baud rates with OVSFACT = 0

Required bit rate (bps)

Programmed divisor

Generated bit rate (bps) Error (%)

Integer (DIVINT) Fraction (DIVFRAC)

921 600 1 (16’h0001) 5 (6’h05) 927 557 0.646

460 800 2 (16’h0002) 11 (6’h0B) 460 447 - 0.077

230 400 4 (16’h0004) 22 (6’h16) 230 218 - 0.079

115 200 8 (16’h0008) 44 (6’h2C) 115 107 - 0.081

57 600 17 (16’h0011) 23 (6’h17) 57 606 0.010

38 400 26 (16’h001A) 3 (6’h03) 38 392 - 0.021

28 800 34 (16’h0022) 46 (6’h2E) 28 802 0.007

19 200 52 (16’h0034) 5 (6’h05) 19 201 0.005

9 600 104 (16’h0068) 11 (6’h0B) 9 599 - 0.010

2 400 416 (16’h01A0) 43 (6’h2B) 2 399 - 0.042

1 200 833 (16’h04B0) 21 (6’h15) 1 200 0

300 3333 (16’h0D05) 21 (6’h15) 300 0

110 9090 (16’h2382) 58 (6’h3A) 110 0

Table 73. Typical baud rates with OVSFACT = 1

Required bit rate (bps)

Programmed divisor

Generated bit rate (bps) Error (%)

Integer (DIVINT) Fraction (DIVFRAC)

1 843 200 1 (16’h0001) 5 (6’h05) 1 855 115 0.646

921 600 2 (16’h0002) 11 (6’h0B) 920 895 - 0.076

460 800 4 (16’h0004) 22 (6’h16) 461 436 - 0.079

230 400 8 (16’h0008) 44 (6’h2C) 230 215 - 0.080

115 200 17 (16’h0011) 23 (6’h17) 115 212 0.010

57 600 34 (16’h0022) 46 (6’h2E) 57 605 0.009

38 400 52 (16’h0034) 5 (6’h05) 38 403 0.008

28800 69 (16’h0045) 28 (6’h1C) 28 802 0.007

19 200 104 (16’h0068) 11 (6’h0B) 19 199 - 0.005

9 600 208 (16’h00D0) 21 (6’h15) 9 600 0

2 400 833 (16’h0341) 21 (6’h15) 2 400 0

1 200 1666 (16’h0682) 43 (6’h2B) 1 199 -0.083

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Required bit rate (bps)

Programmed divisor

Generated bit rate (bps) Error (%)

Integer (DIVINT) Fraction (DIVFRAC)

300 6666 (16’h1A0A) 43 (6’h2B) 299 -0.333

110 18181 (16’h4705) 52 (6’h34) 110 0

3.9.2.3 Hardware flow control

The hardware flow controls feature is fully selectable through RTSEN and CTSEN in UARTCR register, and

allows to control the serial data flow by using the UART_RTS output and UART_CTS input signals.

Figure 14. Hardware flow control between two similar devices

When the RTS flow control is enabled, the UART_RTS signal is asserted until the receive FIFO is filled up to the

programmed watermark level. When the CTS flow control is enabled, the transmitter can only transmit data when

the UART_CTS signal is asserted.

Table 74. Control bits to enable and disable hardware flow control

CTSEN RTSEN Function

0b 0b Both RTS and CTS flow control disabled.

0b 1b Only RTS flow control enabled.

1b 0b Only CTS flow control enabled.

1b 1b Both RTS and CTS flow control enabled.

The RTS flow control logic is linked to the programmable receive FIFO watermark levels. When RTS flow control

is enabled, the UART_RTS is asserted until the receive FIFO is filled up to the watermark level. When the receive

FIFO watermark level is reached, the UART_RTS signal is de-asserted, indicating that there is no more room

to receive any more data. The transmission of data is expected to cease after the current character has been

transmitted. The UART_RTS signal is reasserted when data has been read out of the receive FIFO so that it is

filled to less than the watermark level. If RTS flow control is disabled and the UART is still enabled, then data is

received until the receive FIFO is full, or no more data is transmitted to it.

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If CTS flow control is enabled, then the transmitter checks the UART_CTS signal before transmitting the next

byte. If the UART_CTS signal is asserted, it transmits the byte otherwise, transmission does not occur. The data

continues to be transmitted while UART_CTS is asserted, and the transmit FIFO is not empty. If the transmit FIFO

is empty and the UART_CTS signal is asserted no data is transmitted. If the UART_CTS signal is de-asserted

and CTS flow control is enabled, then the current character transmission is completed before stopping. If CTS

flow control is disabled and the UART is enabled, then the data continues to be transmitted until the transmit FIFO

is empty.

3.9.2.4 Software flow control

Software flow control is enabled through register UART_XFCR bit SFEN.

Software receive flow control

Once the software receive flow control is enabled, the receiver compares the incoming data with the programmed

Xoff values. Different combinations of software receive flow control, which can be selected through SFRMOD,

where only 1 character match is needed or in which 2 Xoff characters must be received sequentially.

Table 75. Control bits to enable and program receive software flow control

SFSEN SFRMOD Function

0b xxb Software flow control disabled.

1b 00b Software receive flow control disabled.

1b 01b Use Xon1, Xoff1 for matching.

1b 10b Use Xon2, Xoff2 for matching.

1b 11b Use Xon1 & Xon2, Xoff1 & Xoff2 for matching.

If received characters match the programmed Xoff values, the transmission stops as soon as the current

character is completely transferred. The interrupt bit XOFFRIS in the raw interrupt register UART_RIS is set.

If the corresponding interrupt mask bit is set, the corresponding bit in the UART_MIS register is set and the UART

interrupt pin is asserted. Following such a transmission suspension, the receiver will monitor incoming characters

for a match with the programmed Xon values. The matching strategy is programmable through SWRFCPROG in

XONANY bit in register UART_XFCR is set, any incoming character is accepted as a valid Xon condition and the

transmission can then resume. The received character is written into the received FIFO.

Note: If the software flow control is enabled, the received Xon/Xoff characters are never written into the received FIFO.

Exceptions to this occur when the special character detection feature is enabled (Xoff2 is then written into FIFO

upon a special character match) and when the Xon-any bit is set.

Note: The received status (parity, framing and break error) of Xon/Xoff characters does not have to be valid for these

characters to be accepted as valid matches.

When the software transmit flow control is enabled through the SFTMOD bit field in the UART_XFCR register, the

transmitter will automatically insert an Xoff character if the received FIFO has passed the received trigger level

(bit field RXIFLSEL in the UART_IFLS register). The RTXDIS (remote transmitter disabled) bit in the UART_FR

Xon character is automatically inserted in the transmission stream and the RTXDIS bit in the UART_FR register is

cleared.

Table 76. Control bits to enable and program transmit software flow control

SFSEN SFTMOD Function

0b xxb Software flow control disabled.

1b 00b Software transmit flow control disabled.

1b 01b Use Xon1, Xoff1 for matching.

1b 10b Use Xon2, Xoff2 for matching.

1b 11b Use Xon1 and Xon2, Xoff1 and Xoff2 for matching.

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Note: After an Xoff character has been transmitted, if the software flow controlled is turned off, a Xon character is

automatically be inserted in the transmission stream and the bit RTXDIS bit in the UART_FR register is cleared.

Note: Transmission of an Xon/Xoff character follows the standard transmission protocol as programmed in the

transmitter registers (word length, parity and so on).

Note: When using the software transmit flow control, there are some cautions to take to manage the interrupt handler.

The software must react on RX interrupt (the flag is raised once the RX FIFO contains the RXIFSEL trigger

level. Then the interrupt handler must first poll the UART_FR.RTXDIS bit until it is set to indicate the Xoff byte

transmission is over and only then read the RX FIFO content. Note that hardware and software flow control

cannot be enabled simultaneously.

Software transmit flow control

When the special character detection feature is enabled through the SPECHAR bit in the UART_XFCR register,

the software flow control is turned off and the receiver compares received characters with the Xoff2 value. When

a match is found, the interrupt bit XOFFRIS in the raw interrupt register UART_RIS is set. If the corresponding

interrupt mask bit is set, the UART interrupt pin is asserted. The transmission is not halted. The special character

is written into the received FIFO. The interrupt bit XOFFIS will be cleared when the corresponding bit in interrupt

clear register is written as 1b.

Note: It is assumed that software flow control is turned off when this feature is used. The received status (i.e. parity,

framing and break error) of special characters does not have to be valid for these characters to be accepted as

valid matches.

3.9.2.5 UART interrupts

There are six individual maskable interrupt sources generated by the UART (single interrupt signal that drives the

NVIC):

•TX FIFO empty interrupt

•Xoff/ special character interrupt

• Receive interrupt

• Transmit interrupt

• Timeout interrupt

• Error interrupt

The user can enable or disable the individual interrupt sources by changing the mask bits in the UART_IMSC

can be read from the UART_RIS register (raw interrupt status) or from the UART_MIS register (masked interrupt

status).

3.9.2.6 TX FIFO empty interrupt

The TX FIFO empty interrupt is asserted whenever the BUSY status bit goes low to indicate that all DATA has

been transmitted. This BUSY bit remains set until the complete byte, including all the stop bits, has been sent

from the shift register. So, the new TX FIFO empty interrupt is asserted when the transmit FIFO and the transmit

shift register are empty.

3.9.2.7 Xoff/ special character interrupt

The Xoff/special character interrupt is asserted whenever an Xoff condition is detected by the receiver (incoming

data matches with the programmable Xoff values), or when a special character detection was performed

(incoming data matches with the Xoff2 and SPECHAR bit set).

3.9.2.8 Receive interrupt

The receive interrupt is asserted HIGH when one of the following conditions occurs:

• If the FIFOs are enabled and the number of characters received reaches the programmed trigger watermark

level. The receive interrupt is cleared by reading data from the receive FIFO until it becomes less than the

programmed watermark level, or by clearing the interrupt by writing a 1b to the corresponding bit in the

UART_ICR register.

• If the FIFOs are disabled (have a depth of one location) and there is a data present in the receiver single

location. It is cleared by performing a single read.

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3.9.2.9 Transmit interrupt

The transmit interrupt is asserted HIGH when one of the following conditions occurs:

• If the FIFOs are enabled and the number of characters in the transmit FIFO is less than the programmed

watermark level. It is cleared by performing writes to the transmit FIFO until it holds more characters than

the programmed watermark level, or by clearing the interrupt by software.

•If the FIFOs are disabled (have a depth of one location) and there is no data present in the transmitter

single location. It is cleared by performing a single write to the transmit FIFO, or by clearing the interrupt by

software.

Note: The transmit FIFO service interrupt is based on a transition through a level, rather than on the level itself. When

the interrupt and the UART are enabled before any data is written to the transmit FIFO, the interrupt is not set.

The interrupt is only set once written data leaves the single location of the transmit FIFO and it becomes empty.

Note: When the TX FIFO is disabled, the DATA can be written on the bottom of the FIFO during the transmission of a

previous DATA, or in another words, when the holding register is busy.

Note: The interrupt is de-asserted when we write the next DATA on the bottom of the TX FIFO. If we write DATA only

on the holding register and the bottom of the TX FIFO is empty, the only way to clear the interrupt is by the

software.

3.9.2.10 Timeout interrupt

The receive timeout interrupt is asserted when the receive FIFO is not empty, and no further data is received (or

no correct start bit of a frame is detected in the RX line) over a programmable timeout period. This mechanism

ensures that the user is aware that data is still present in the receive FIFO and requires servicing. The receive

timeout interrupt is cleared either when the FIFO becomes empty through reading all the data (or by reading the

holding register), or when a 1b is written to the corresponding bit of the UART_ICR register.

3.9.2.11 Error interrupt

The error interrupt is asserted when an error occurs in the reception of data by the UART. The interrupt can be

caused by the following error conditions:

• Framing

•Parity

• Break

• Overrun

The cause of the interrupt is available by reading the UART_RIS or UART_MIS registers. The interrupt can be

cleared by writing to the relevant bits of the UART_ICR register.

3.9.3 UART registers

UART peripheral base address (UART_BASE_ADDR) 0x40300000.

Table 77. UART registers

Address

offset Name RW Reset Description

0x00 DR RW 0x00000000 Data register. Refer to the detailed description below.

0x04 RSR R 0x00000000 Receive status register. Refer to the detailed description below.

0x04 ECR W 0x00000000 Error clear register. A write to this register clears the framing (FE),

parity (PE), break (BE), and overrun (OE) errors.

0x0C TIMEOUT RW 0x000001FF Timeout register. Refer to the detailed description below.

0x18 FR R 0x00001E90 Flag register. Refer to the detailed description below.

0x1C LCRH_RX RW 0x00000000 Receive line control register. Refer to the detailed description below.

0x24 IBRD RW 0x00000000 Integer baud rate register. Refer to the detailed description below.

0x28 FBRD RW 0x00000000 Fractional baud rate register. Refer to the detailed description below.

0x2C LCRH_TX RW 0x00000000 Transmit line control register. Refer to the detailed description below.

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Address

offset Name RW Reset Description

0x30 CR RW 0x00040300 Control register. Refer to the detailed description below.

0x34 IFLS RW 0x00000012 Interrupt FIFO level select register. Refer to the detailed description

below.

0x38 IMSC RW 0x00000000 Interrupt mask set/clear register. Refer to the detailed description

below.

0x3C RIS R 0x00000000 Raw interrupt status register. Refer to the detailed description below.

0x40 MIS R 0x00000000 Masked interrupt status register. Refer to the detailed description

below.

0x44 ICR W 0x00000000 Interrupt clear register. Refer to the detailed description below.

0x48 DMACR RW 0x00000000 DMA control register. Refer to the detailed description below.

0x50 XFCR RW 0x00000000 XON/XOFF control register. Refer to the detailed description below.

0x54 XON1 RW 0x00000000 Register used to store the Xon1 character used for software flow

control. Refer to the detailed description below.

0x58 XON2 RW 0x00000000 Register used to store the Xon2 character used for software flow

control. Refer to the detailed description below.

0x5C XOFF1 RW 0x00000000 Register used to store the Xoff1 character used for software flow

control. Refer to the detailed description below.

0x60 XOFF2 RW 0x00000000 Register used to store the Xoff2 character used for software flow

control. Refer to the detailed description below.

Table 78. UART - DR register description: address offset UART_BASE_ADDR+0x00

Bit Field name Reset RW Description

7:0 DATA 0x0 RW

UART data register:

Receive: read data character.

Transmit: write data character.

8 FE 0x0 R

Frame error. This bit is set to 1 if the received character did not have a valid

stop bit. In FIFO mode, this error is associated with the character at the top

of the FIFO.

9 PE 0x0 R

Parity error. This bit is set to 1 if the parity of the received data character

does not match the parity selected as defined by bits 2 and 7 of the

LCRH_RX register. In FIFO mode, this error is associated with the character

at the top of the FIFO.

10 BE 0x0 R

Break error. This bit is set to 1 if a break condition was detected, indicating

that the received data input was held low for longer than a full-word

transmission time (defined as start, data, parity and stop bits). In FIFO

mode, this error is associated with the character at the top of the FIFO.

When a break occurs, only one 0 character is loaded into the FIFO. The

next character is only enabled after the receive data input goes to HIGH

(marking state), and the next valid start bit is received

11 OE 0x0 R

Overrun error. This bit is set to 1 if data is received and the receive FIFO is

already full. This is cleared to 0b once there is an empty space in the FIFO

and a new character can be written to it. The FIFO content remains valid

since no further data is written when the FIFO is full, only the content of the

shift register is overwritten.

31:12 RESERVED 0x0 R RESERVED

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Table 79. UART - RSR register description: address offset UART_BASE_ADDR+0x04

Bit Field name Reset RW Description

0 FE 0x0 R

Frame error. This bit is set to 1 if the received character did not have a valid

stop bit (a valid stop bit is 1).This bit is cleared to 0b after a write to ECR.

In FIFO mode, this error is associated with the character at the top of the

FIFO.

1 PE 0x0 R

Parity error. This bit is set to 1 if the parity of the received data character

does not match the parity selected as defined by bits 2 and 7 of the

LCRH_RX register. This bit is cleared to 0b after a write to ECR. In FIFO

mode, this error is associated with the character at the top of the FIFO.

2BE 0x0 R

Break error. This bit is set to 1 if a break condition was detected, indicating

that the received data input was held low for longer than a full-word

transmission time (defined as start, data, parity and stop bits). This bit is

cleared to 0b after a write to ECR. In FIFO mode, this error is associated

with the character at the top of the FIFO. When a break occurs, only one 0

character is loaded into the FIFO. The next character is only enabled after

the receive data input goes to HIGH (marking state), and the next valid start

bit is received.

3 OE 0x0 R

Overrun error. This bit is set to 1 if data is received and the receive FIFO

is already full. This is cleared to 0 by a write to ECR (data value is not

important). The FIFO contents remain valid since no further data is written

when the FIFO is full, only the content of the shift register are overwritten.

The CPU or DMA must now read the data in order to empty the FIFO.

31:4 RESERVED 0x0 R RESERVED

Table 80. UART - TIMEOUT register description: address offset UART_BASE_ADDR+0x0C

Bit Field name Reset RW Description

21:0 PERIOD 0x1FF RW

Timeout period configuration. This bit field contains the timeout period

for the UART timeout interrupt assertion. The receive timeout interrupt

is asserted when the receive FIFO is not empty and no further data

is received over a programmed timeout period. The duration before the

timeout interrupt assert is calculated by the following formula:

timeout = PERIOD / (OverSamplingFactor * BaudRate) Where

OverSamplingFactor is:

16 if OVSFACT is 0

8 if OVSFACT is 1.

31:22 RESERVED 0x0 RW RESERVED

Table 81. UART - FR register description: address offset UART_BASE_ADDR+0x18

Bit Field name Reset RW Description

0 CTS 0x0 R Clear to send.

2:1 RESERVED 0x0 R RESERVED

3 BUSY 0x0 R

UART Busy. If this bit is set to 1, the UART is busy transmitting data. This

bit remains set until the complete byte, including all the stop bits, has been

sent from the shift register. However, if the transmit section of the UART

is disabled in the middle of a transmission, the BUSY bit gets cleared.

This bit is set again once the transmit section is re-enabled to complete

the remaining transmission. This bit is set as soon as the transmit FIFO

becomes nonempty (regardless of whether the UART is enabled or not).

4 RXFE 0x1 R

Receive FIFO empty. If the FIFO is disabled (bit FEN = 0b), this bit is set

when the receive holding register is empty. If the FIFO is enabled (FEN =

1b), the RXFE bit is set when the receive FIFO is empty.

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Bit Field name Reset RW Description

5 TXFF 0x0 R

Transmit FIFO full. If the FIFO is disabled (bit FEN = 0b), this bit is set when

the transmit holding register is full. If the FIFO is enabled (FEN = 1b), the

TXFF bit is set when the transmit FIFO is full.

6 RXFF 0x0 R

Receive FIFO full. If the FIFO is disabled (bit FEN = 0b), this bit is set when

the receive holding register is full. If the FIFO is enabled (FEN = 1b), the

RXFF bit is set when the receive FIFO is full.

7 TXFE 0x1 R

Transmit FIFO empty. If the FIFO is disabled (bit FEN = 0b), this bit is set

when the transmit holding register is empty. If the FIFO is enabled (FEN =

1b), the TXFE bit is set when the transmit FIFO is empty.

8 RESERVED 0x0 R RESERVED

9 DCTS 0x1 R Delta clear to send. This bit is set CTS changes since the last read of the

FR register.

12:10 RESERVED 0x7 R RESERVED

13 RTXDIS 0x0 R

Remote transmitter disabled (software flow control). This bit indicates an

Xoff character was sent to the remote transmitter to stop it after the received

FIFO has passed over its trigger limit. This bit is cleared when a Xon

character is sent to the remote transmitter.

31:14 RESERVED 0x0 R RESERVED

Table 82. UART - LCRH_RX register description: address offset UART_BASE_ADDR+0x1C

Bit Field name Reset RW Description

0 RESERVED 0x0 RW RESERVED

1 PEN_RX 0x0 RW

RX parity enable:

0: Parity disabled.

1: Parity enabled.

2 EPS_RX 0x0 RW

RX even parity selection, when the parity is enabled.

0: Odd parity generation and checking is performed during reception, which

check for an odd number of 1s in data and parity bits.

1: Even parity generation and checking is performed during reception, which

check for an even number of 1s in data and parity bits.

3 STP2_RX 0x0 RW

RX two stop bits select. This bit enables the check for two stop bits being

received:

0: 1 stop bit received.

1: 2 stop bits received.

4 FEN_RX 0x0 RW

RX enable FIFOs. This bit enables/disables the receive RX FIFO buffer:

0: RX FIFO is disabled (character mode).

1: RX FIFO is enabled.

6:5 WLEN_RX 0x0 RW

RX word length. This bit field indicates the number of data bits received in a

frame as follows:

00b: 5 bits.

01b: 6 bits.

10b: 7 bits.

11b: 8 bits.

7SPS_RX 0x0 RW

RX stick parity select:

0: stick parity is disabled.

1: when PEN_RX = 1b (parity enabled) and EPS_RX = 1b (even parity),

the parity is checked as a 0. When PEN_RX = 1b and EPS_RX = 0b (odd

parity), the parity bit is checked as a 1.

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Bit Field name Reset RW Description

31:8 RESERVED 0x0 RW RESERVED

Table 83. UART - IBRD register description: address offset UART_BASE_ADDR+0x24

Bit Field name Reset RW Description

15:0 DIVINT 0x0 RW

Baud rate integer. The baud rate divisor is calculated as follows:

When OVSFACT = 0b in the CR register: Baud rate divisor = (frequency

(UARTCLK)/(16*Baud rate))

When OVSFACT = 1b in CR register: Baud rate divisor = (frequency

(UARTCLK)/(8*Baud rate))

where frequency (UARTCLK) is the UART reference clock frequency. The

baud rate divisor comprises the integer value (DIVINT) and the fractional

value (DIVFRAC). The contents of the IBRD and FBRD registers are

not updated until transmission or reception of the current character has

completed.

31:16 RESERVED 0x0 RW RESERVED

Table 84. UART - FBRD register description: address offset UART_BASE_ADDR+0x28

Bit Field name Reset RW Description

5:0 DIVFRAC 0x0 RW

Baud rate fraction. Baud rate integer. The baud rate divisor is calculated as

follows:

When OVSFACT = 0b in the CR register: baud rate divisor = (frequency

(UARTCLK)/(16*Baud rate))

When OVSFACT = 1b in CR register: baud rate divisor = (frequency

(UARTCLK)/(8*Baud rate))

where frequency (UARTCLK) is the UART reference clock frequency. The

baud rate divisor comprises the integer value (DIVINT) and the fractional

value (DIVFRAC). The contents of the IBRD and FBRD registers are

not updated until transmission or reception of the current character has

completed.

31:6 RESERVED 0x0 RW RESERVED

Table 85. UART - LCRH_TX register description: address offset UART_BASE_ADDR+0x2C

Bit Field name Reset RW Description

0 BRK 0x0 RW

Send break. This bit allows a continuous low-level to be forced on TX

output, after completion of the current character. This bit must be asserted

for at least one complete frame transmission time in order to generate a

break condition. The transmit FIFO contents remain unaffected during a

break condition.

0: Normal transmission.

1: Break condition transmission.

1 PEN_TX 0x0 RW

TX parity enable:

0: Parity disabled.

1: Parity enable.

2 EPS_TX 0x0 RW

TX even parity select. This bit selects the parity generation, when the parity

is enabled (PEN_TX =1b). This bit has no effect when parity is disabled

(PEN_TX = 0b).

0: Odd parity generation and checking is performed during transmission,

which check for an odd number of 1s in data and parity bits.

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Bit Field name Reset RW Description

1: Even parity generation and checking is performed during transmission,

which check for an even number of 1s in data and parity bits.

3 STP2_TX 0x0 RW

TX two-stop bits select. This bit enables the check for two stop bits being

received:

0: 1 stop bit received.

1: 2 stop bits received.

4 FEN_TX 0x0 RW

TX Enable FIFO. This bit enables/disables the transmit TX FIFO buffer:

0: TX FIFO is disabled (character mode), i.e. the TX FIFO becomes a

1-byte deep holding register.

1: TX FIFO is enabled.

6:5 WLEN_TX 0x0 RW

TX word length. This bit field indicates the number of data bits transmitted in

a frame as follows:

00b: 5 bits.

01b: 6 bits.

10b: 7 bits.

11b: 8 bits.

7SPS_TX 0x0 RW

TX stick parity check:

0: stick parity disable.

1: when PEN_TX = 1b (parity enabled) and EPS_TX = 1b (even parity), the

parity is transmitted as a 0. When PEN_TX = 1b and EPS_TX = 0b (odd

parity), the parity bit is transmitted as a 1.

31:8 RESERVED 0x0 RW RESERVED

Table 86. UART - CR register description: address offset UART_BASE_ADDR+0x30

Bit Field name Reset RW Description

0 EN 0x0 RW

UART enable. This bit enables the UART.

0: UART is disabled.

1: UART is enabled. Data transmission and reception can occur.

When the UART is disabled in the middle of transmission or

reception, it completes the current character before stopping.

2:1 RESERVED 0x0 RW RESERVED

3 OVSFACT 0x0 RW

UART oversampling factor. This bit enables the UART oversampling

factor. If UARTCLK is 16 MHz thus max. baud-rate is 1 Mbaud when

OVSFACT = 0b, and 2 Mbaud when OVSFACT = 1b.

0: UART it is 16 UARTCLK clock cycles.

1: UART it is 8 UARTCLK clock cycles.

7:4 RESERVED 0x0 RW RESERVED

8 TXE 0x1 RW

Transmit enable.

0b: UART TX disabled.

1b: UART TX enabled.

9 RXE 0x1 RW

Receive enable.

0b: UART RX disabled.

1b: UART RX enabled.

10 RESERVED 0x0 RW RESERVED

11 RTS 0x0 RW Request to send.

0: RTS is high.

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Bit Field name Reset RW Description

1: RTS is low.

13:12 RESERVED 0x0 RW RESERVED

14 RTSEN 0x0 RW

RTS hardware flow control enable.

0b: RTS disabled.

1b: RTS enabled. Data is only requested when there is space in the

receive FIFO for it to be received.

15 CTSEN 0x0 RW

CTS hardware flow control enable.

0b: CTS disabled.

1b: CTS enabled. Data is only transmitted when the CTS is

asserted.

19:16 STA_B_DURATION 0x4 RW

START bit duration receiver state. These bits can be used to

configure the START bit duration (in clock cycles) to get the bit

sampled in the middle of the UART receiver. These bits can be

used only when using high baud rates (IBRD = 1, FBRD ≥ 0 and

OVSFACT = 1). Below the formula to calculate the START bit

duration receiver state:

STA_B_DURATION = Integer(Fuartclk/(2* BAUD RATE)) - 1

Example: when UARTCLK = 16 MHz and BAUD RATE = 2.0 Mbps

then STA_B_DURATION = 4 - 1 = 3. STA_B_DURATION field

should be configured with 4'b0011.

31:20 RESERVED 0x0 RW RESERVED

Table 87. UART - IFLS register description: address offset UART_BASE_ADDR+0x34

Bit Field name Reset RW Description

2:0 TXIFLSEL 0x2 RW

Transmit interrupt FIFO level select. This bit field selects the trigger points

for TX FIFO interrupt:

000b: Interrupt when FIFO ≥ 1/64 empty.

001b: Interrupt when FIFO ≥ 1/32 empty.

010b: Interrupt when FIFO ≥ 1/16 empty.

011b: Interrupt when FIFO ≥ 1/8 empty.

100b: Interrupt when FIFO ≥ 1/4 empty.

101b: Interrupt when FIFO ≥ 1/2 empty.

110b: Interrupt when FIFO ≥ 3/4 empty.

5:3 RXIFLSEL 0x2 RW

Receive interrupt FIFO level select. This bit field selects the trigger points

for RX FIFO interrupt:

000b: Interrupt when FIFO ≥ 1/64 full.

001b: Interrupt when FIFO ≥ 1/32 full.

010b: Interrupt when FIFO ≥ 1/16 full.

011b: Interrupt when FIFO ≥ 1/8 full.

100b: Interrupt when FIFO ≥ 1/4 full.

101b: Interrupt when FIFO ≥ 1/2 full.

110b: Interrupt when FIFO ≥ 3/4 full.

31:6 RESERVED 0x0 RW RESERVED

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Table 88. UART - IMSC register description: address offset UART_BASE_ADDR+0x38

Bit Field name Reset RW Description

0 RESERVED 0x0 RW RESERVED

1 CTSMIM 0x0 RW

Clear to send modem interrupt mask. On a read, the current mask for the

CTSMIM interrupt is returned.

0: Clears the mask (interrupt is disabled).

1: Sets the mask (interrupt is enabled).

3:2 RESERVED 0x0 RW RESERVED

4 RXIM 0x0 RW

Receive interrupt mask. On a read, the current mask for the RXIM interrupt

is returned.

0: Clears the mask (interrupt is disabled).

1: Sets the mask (interrupt is enabled).

5 TXIM 0x0 RW

Transmit interrupt mask. On a read, the current mask for the TXIM interrupt

is returned.

0: Clears the mask (interrupt is disabled).

1: Sets the mask (interrupt is enabled).

6 RTIM 0x0 RW

Receive timeout interrupt mask. On a read, the current mask for the RTIM

interrupt is returned.

0: Clears the mask (interrupt is disabled).

1: Sets the mask (interrupt is enabled).

7 FEIM 0x0 RW

Framing error interrupt mask. On a read, the current mask for the FEIM

interrupt is returned.

0: Clears the mask (interrupt is disabled).

1: Sets the mask (interrupt is enabled).

8 PEIM 0x0 RW

Parity error interrupt mask. On a read, the current mask for the PEIM

interrupt is returned.

0: Clears the mask (interrupt is disabled).

1: Sets the mask (interrupt is enabled).

9 BEIM 0x0 RW

Break error interrupt mask. On a read, the current mask for the BEIM

interrupt is returned.

0: Clears the mask (interrupt is disabled).

1: Sets the mask (interrupt is enabled).

10 OEIM 0x0 RW

Overrun error interrupt mask. On a read, the current mask for the OEIM

interrupt is returned.

0: Clears the mask (interrupt is disabled).

1: Sets the mask (interrupt is enabled).

11 XOFFIM 0x0 RW

XOFF interrupt mask. On a read, the current mask for the XOFFIM interrupt

is returned.

0: Clears the mask (interrupt is disabled).

1: Sets the mask (interrupt is enabled).

12 TXFEIM 0x0 RW

TX FIFO empty interrupt mask. On a read, the current mask for the TXFEIM

interrupt is returned.

0: Clears the mask (interrupt is disabled).

1: Sets the mask (interrupt is enabled).

31:13 RESERVED 0x0 RW RESERVED

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Table 89. UART - RIS register description: address offset UART_BASE_ADDR+0x3C

Bit Field name Reset RW Description

0 RESERVED 0x0 R RESERVED

1 CTSMIS 0x0 R

Clear to send interrupt status.

0: The interrupt is not pending.

1: The interrupt is pending.

3:2 RESERVED 0x0 R RESERVED

4 RXIS 0x0 R

Receive interrupt status.

0: The interrupt is not pending.

1: The interrupt is pending.

5 TXIM 0x0 R

Transmit interrupt status.

0: The interrupt is not pending.

1: The interrupt is pending.

6 RTIS 0x0 R

Receive timeout interrupt status.

0: The interrupt is not pending.

1: The interrupt is pending.

7 FEIS 0x0 R

Framing error interrupt status.

0: The interrupt is not pending.

1: The interrupt is pending.

8 PEIS 0x0 R

Parity error interrupt status.

0: The interrupt is not pending.

1: The interrupt is pending.

9 BEIS 0x0 R

Break error interrupt status.

0: The interrupt is not pending.

1: The interrupt is pending.

10 OEIS 0x0 R

Overrun error interrupt status.

0: The interrupt is not pending.

1: The interrupt is pending.

11 XOFFIS 0x0 R

XOFF interrupt status.

0: The interrupt is not pending.

1: The interrupt is pending.

12 TXFEIS 0x0 R

TX FIFO empty interrupt status.

0: The interrupt is not pending.

1: The interrupt is pending.

31:13 RESERVED 0x0 R RESERVED

Table 90. UART - MIS register description: address offset UART_BASE_ADDR+0x40

Bit Field name Reset RW Description

0 RESERVED 0x0 R RESERVED

1 CTSMMIS 0x0 R

Clear to send masked interrupt status.

0: The interrupt is not pending.

1: The interrupt is pending.

3:2 RESERVED 0x0 R RESERVED

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Bit Field name Reset RW Description

4 RXMIS 0x0 R

Receive masked interrupt status.

0: The interrupt is not pending.

1: The interrupt is pending.

5 TXMIS 0x0 R

Transmit masked interrupt status.

0: The interrupt is not pending.

1: The interrupt is pending.

6 RTMIS 0x0 R

Receive timeout masked interrupt status.

0: The interrupt is not pending.

1: The interrupt is pending.

7 FEMIS 0x0 R

Framing error masked interrupt status.

0: The interrupt is not pending.

1: The interrupt is pending.

8 PEMIS 0x0 R

Parity error masked interrupt status.

0: The interrupt is not pending.

1: The interrupt is pending.

9 BEMIS 0x0 R

Break error masked interrupt status.

0: The interrupt is not pending.

1: The interrupt is pending.

10 OEMIS 0x0 R

Overrun error masked interrupt status.

0: The interrupt is not pending.

1: The interrupt is pending.

11 XOFFMIS 0x0 R

XOFF interrupt masked status.

0: The interrupt is not pending.

1: The interrupt is pending.

12 TXFEMIS 0x0 R

TX FIFO empty masked interrupt status.

0: The interrupt is not pending.

1: The interrupt is pending.

31:13 RESERVED 0x0 R RESERVED

Table 91. UART - ICR register description: address offset UART_BASE_ADDR+0x44

Bit Field name Reset RW Description

0 RESERVED 0x0 RW RESERVED

1 CTSMIC 0x0 W

Clear to send modem interrupt clear.

0: No effect.

1: Clears the interrupt.

3:2 RESERVED 0x0 RW RESERVED

4 RXIC 0x0 W

Receive interrupt clear.

0: No effect.

1: Clears the interrupt.

5 TXIC 0x0 W

Transmit interrupt clear.

0: No effect.

1: Clears the interrupt.

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Bit Field name Reset RW Description

6 RTIC 0x0 W

Receive timeout interrupt clear.

0: No effect.

1: Clears the interrupt.

7 FEIC 0x0 W

Framing error interrupt clear.

0: No effect.

1: Clears the interrupt.

8 PEIC 0x0 W

Parity error interrupt clear.

0: No effect.

1: Clears the interrupt.

9 BEIC 0x0 W

Break error interrupt clear.

0: No effect.

1: Clears the interrupt.

10 OEIC 0x0 W

Overrun error interrupt clear.

0: No effect.

1: Clears the interrupt.

11 XOFFIC 0x0 W

XOFF interrupt clear.

0: No effect.

1: Clears the interrupt.

12 TXFEIC 0x0 W

TX FIFO empty interrupt clear.

0: No effect.

1: Clears the interrupt.

31:13 RESERVED 0x0 RW RESERVED

Table 92. UART - DMACR register description: address offset UART_BASE_ADDR+0x48

Bit Field name Reset RW Description

0 RXDMAE 0x0 RW

Receive DMA enable bit.

0: DMA mode is disabled for reception.

1: DMA mode is enabled for reception.

1 TXDMAE 0x0 RW

Transmit DMA enable bit.

0: DMA mode is disabled for transmit.

1: DMA mode is enabled for transmit.

2 RESERVED 0x0 RW RESERVED

3 DMAONERR 0x0 RW

DMA on error.

0: UART error interrupt status has no impact in receive DMA mode.

1: DMA receive requests are disabled when the UART error interrupt is

asserted.

31:4 RESERVED 0x0 RW RW RESERVED

Table 93. UART - XFCR register description: address offset UART_BASE_ADDR+0x50

Bit Field name Reset RW Description

0 SFEN 0x0 RW Software flow control enable.

0: Software flow control disable.

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Bit Field name Reset RW Description

1: software flow control enable.

2:1 SFRMOD 0x0 RW

Software receive flow control mode:

00b: Receive flow control is disabled.

01b: Xon1, Xoff1 characters are used in receiving software flow control.

10b: Xon2, Xoff2 characters are used in receiving software flow control.

11b: Xon1 and Xon2, Xoff1 and Xoff2 characters are used in receiving

software flow control.

4:3 SFTMOD 0x0 RW

Software transmit flow control mode:

00b: Transmit flow control is disabled.

01b: Xon1, Xoff1 characters are used in transmitting software flow control.

10b: Xon2, Xoff2 characters are used in transmitting software flow control.

11b: Xon1 and Xon2, Xoff1 and Xoff2 characters are used in transmitting

software flow control.

5 XONANY 0x0 RW

Xon-any bit:

0: Incoming character must match Xon programmed value(s) to be a valid

Xon.

1: Any incoming character is considered as a valid Xon.

6 SPECHAR 0x0 RW

Special character detection bit.

0: Special character detection disabled.

1: Special character detection enabled.

31:7 RESERVED 0x0 RW RESERVED

Table 94. UART - XON1 register description: address offset UART_BASE_ADDR+0x54

Bit Field name Reset RW Description

7:0 XON1 0x0 RW Value of Xon1 character used in the software flow control

31:8 RESERVED 0x0 RW RW RESERVED

Table 95. UART - XON2 register description. Address offset UART_BASE_ADDR+0x58.

Bit Field name Reset RW Description

7:0 XON2 0x0 RW Value of Xon2 character used in the software flow control.

31:8 RESERVED 0x0 RW RESERVED

Table 96. UART - XOFF1 register description. Address offset UART_BASE_ADDR+0x5C.

Bit Field name Reset RW Description

7:0 XOFF1 0x0 RW Value of Xoff1 character used in the software flow control.

31:8 RESERVED 0x0 RW RESERVED

Table 97. UART - XOFF2 register description. Address offset UART_BASE_ADDR+0x60.

Bit Field name Reset RW Description

7:0 XOFF2 0x0 RW Value of Xoff2 character used in the software flow control.

31:8 RESERVED 0x0 RW RESERVED

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Note: All RESERVED fields inside registers must always be written with their default values.

3.10 I²C

3.10.1 Introduction

The BlueNRG-2 integrates two I²C controllers in the QFN32 package (I2C2 and I2C1), and one in the WCSP34

package (I2C2). The I²C controller interface is designed to support the physical and data link layer according to

I²C standard revision 3.0 and provides a low-cost interconnection between ICs.

Main features are:

•Up to 400 Kb/s in fast mode and up to 100 Kb/s in standard mode.

•Operating modes supported are master mode, slave mode, master/slave mode for multi-master system with

bus arbitration.

• Programmable 7-bit or 10-bit addressing (also with combined formats).

• Programmable start byte procedure.

• 16-byte depth RX FIFO and 16-byte depth TX FIFO.

• Spike digital filtering on the SDA and SCL lines.

• Control timing constraint defined by the I²C standard.

• Support for direct memory access (DMA).

3.10.2 Functional description

Two wires, serial data (SDA) and serial clock (SCL) carry information between the devices connected to the bus.

Each device has a unique address and can operate as either a transmitter or receiver, depending on the function

of the device. A master is the device that initiates a data transfer on the bus and generates the clock signal. Any

device addressed is considered at that time a slave. The I²C bus is a multi-master bus where more than one

device is capable of controlling the bus. This means that more than one master could try to initiate a data transfer

at the same time. The arbitration procedure relies on the wired-AND connection of all I²C interfaces to the I²C bus.

If two or more masters try to put information onto the bus, the first to produce a ‘one’ when the other produces

a ‘zero’ will lose the arbitration. The clock signals during arbitration are a synchronized combination of the clocks

generated by the masters using the wired-AND connection to the SCL line. Generation of clock signals on the I²C

bus is always the responsibility of master devices; each master generates its own clock signals when transferring

data to the bus. Bus clock signals from a master can only be altered when they are stretched by a slow slave

device holding down the clock line, or by another master when arbitration occurs.

Two modes:

• Standard mode with bit rate up to 100 Kb/s

• Fast mode with bit rate up to 400 Kb/s

3.10.2.1 I²C FIFO management

The transmit and receive paths are buffered with internal FIFO memory enabling up to 16 bytes to be stored

independently in both transmit and receive modes. The FIFOs status can be checked using the I²C interrupts.

There is a programmable threshold value for each FIFO. When the number of entries is greater for the receive

FIFO or less for the transmit FIFO, an interrupt is set.

3.10.2.2 I²C clock rate calculation

To define the I²C clock rate generation there is one register to configure: BRCR. The clock rate can be calculated

using this formula:

Where:

• fI2C is the I²C peripheral clock, clocked on the system clock divided by 3.

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• BRCNT2 is a field of the BRCR register.

• Foncycle depends on a programmable field of the CR register:

–CR: FON = “00” → Filter the clock spike wide = 0 → Foncycle = 1

– CR: FON = “01” → Filter the clock spike wide = 1 → Foncycle = 3

– CR: FON = “10” → Filter the clock spike wide = 2 → Foncycle = 4

– CR: FON = “11” → Filter the clock spike wide = 4 → Foncycle = 6

The minimum input clock frequency for the I²C is:

• 1.4 MHz if the I²C is in standard mode at 100 kHz.

• 7.2 MHz if the I²C is in fast mode at 400 kHz.

3.10.2.3 I²C configuration

Following a reset, the I²C logic is disabled and must be configured when in this state.

The control register (CR) and baud rate register (BRCR) need to be programmed to configure the following

parameters of the peripheral:

•Master or slave.

•7- or 10-bit addressing mode.

• Speed mode.

• Clock rate.

Note: If in slave mode, the SCR register has to be programmed with the selected slave address.

Then, if in master mode, the MCR register is used to define the transaction:

• Read or write.

• Slave addresses (7- or 10-bit) to communicate with.

• Addressing a 7- or 10-bit slave address.

• Stop condition, to generate a stop or restart condition at the end of the transaction (for consecutive

transactions).

• Transaction length.

Note: For a master write, the data to transmit have to be written to the transmit FIFO in the I2C_TFR register. For a

master read, when the master transaction is done, data are available in the receive FIFO in I2C_RFR.

3.10.2.4 DMA interface

The I²C controller includes a specific DMA interface. The following section describes the signals interface, data

flow and programming model for the RX and the TX paths.

The DMA interfaces are separated for each path and two DMA request channels shall be used for a device.

In RX mode, a DMA transfer based on a single descriptor shall be used and the DMA RX channel must be

programmed for a peripheral-to-memory transfer where the flow controller is the DMA. Each descriptor is related

to a single I²C transaction (master read or write-to-slave operation) and no linked list item should be used. The

transfer length is programmed on the DMA and the termination of the frame transfer is notified by the assertion

of the related interrupt I2C_RISR:STD or I2C_RISR:MTD bits. In case of read-from-slave operation, on the DMA

(master device) the transfer length shall be programmed according to the I2C_MCR:LENGTH register field. In

case of write-to-slave operation, on the DMA (slave device) the maximum length (not the real length because it is

unknown) shall be programmed.

In TX mode, a DMA transfer based on a single descriptor shall be used and the DMA TX channel must be

programmed for a memory-to-peripheral transfer where the flow controller is the DMA. Each descriptor is related

to a single I²C transaction (master write or read-from-slave operation) and no linked list item should be used. The

transfer length is programmed on the DMA and the termination of the frame transfer is notified by the assertion

of the related interrupt I2C_RISR:STD or I2C_RISR:MTD bits. In case of write-to-slave operation, on the DMA

(master device) the transfer length shall be programmed according to the I2C_MCR:LENGTH register field. In

case of read-from-slave operation, on the DMA (slave device) the maximum length (not the real length because it

is unknown) shall be programmed.

3.10.3 I²C registers

I2C2 peripheral base address (I2C2_BASE_ADDR) 0x40A00000

I2C1 peripheral base address (I2C1_BASE_ADDR) 0x40B00000

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Table 98. I2Cx registers

Address

offset Name RW Reset Description

0x00 CR RW 0x00000000 I²C control register. Refer to the detailed description below.

0x04 SCR RW 0x000F0055 I²C slave control register. Refer to the detailed description below.

0x0C MCR RW 0x00000000 I²C master control register. Refer to the detailed description

below.

0x10 TFR RW 0x00000000 I²C transmit FIFO register. Refer to the detailed description

below.

0x14 SR R 0x00000000 I²C status register. Refer to the detailed description below.

0x18 RFR R 0x00000000 I²C receive FIFO register. Refer to the detailed description below.

0x1C TFTR RW 0x00000000 I²C transmit FIFO threshold register. Refer to the detailed

description below.

0x20 RFTR RW 0x00000000 I²C receive FIFO threshold register. Refer to the detailed

description below.

0x24 DMAR RW 0x00000000 I²C DMA register. Refer to the detailed description below.

0x28 BRCR RW 0x00000008 I²C baud-rate counter register. Refer to the detailed description

below.

0x2C IMSCR RW 0x00000000 I²C interrupt mask set/clear register. Refer to the detailed

description below.

0x30 RISR R 0x00000013 I²C raw interrupt status register. Refer to the detailed description

below.

0x34 MISR R 0x00000000 I²C masked interrupt status register. Refer to the detailed

description below.

0x38 ICR RW 0x00000000 I²C interrupt clear register. Refer to the detailed description

below.

0x4C THDDAT RW 0x00000014 I²C hold time data. Refer to the detailed description below.

0x50 THDSTA_FST_STD RW 0x003F00E2 I²C hold time start condition F/S. Refer to the detailed description

below.

0x54 RESERVED RW 0x00000019 RESERVED

0x58 TSUSTA_FST_STD RW 0x001D00E2 I²C setup time start condition F/S. Refer to the detailed

description below.

Table 99. I2C - CR register description: address offset I2CX_BASE_ADDR+0x00

Bit Field name Reset RW Description

0 PE 0x0 RW

I²C enable disable:

0: I²C disable.

1: I²C enable.

This bit when deasserted works as software reset for I²C peripheral.

2:1 OM 0x0 RW

Select the operating mode:

00b: Slave mode. The peripheral can only respond (transmit/receive)

when addressed by a master device

01b: Master mode. The peripheral works in a multi-master system where

itself cannot be addressed by another master device. It can only initiate a

new transfer as master device.

10b: Master/slave mode. The peripheral works in a multi-master system

where itself can be addressed by another master device, besides to

initiate a transfer as master device.

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Bit Field name Reset RW Description

3 SAM 0x0 RW

Slave addressing mode. SAM defines the slave addressing mode when

the peripheral works in slave or master/slave mode. The received address

is compared with the content of the register SCR.

0: 7-bit addressing mode.

1: 10-bit addressing mode.

5:4 SM 0x0 RW

Speed mode. SM defines the speed mode related to the serial bit rate:

0: Standard mode (up to 100 k/s).

1: Fast mode (up to 400 k/s).

6 SGCM 0x0 RW

Slave general call mode defines the operating mode of the slave controller

when a general call is received. This setting does not affect the hardware

general call that is always managed in transparent mode.

0: transparent mode, the slave receiver recognizes the general call but

any action is taken by the hardware after the decoding of the message

included in the Rx FIFO.

1: direct mode, the slave receiver recognizes the general call and

executes directly (without software intervention) the related actions. Only

the status code word is stored in the I2C_SR register for notification to the

application.

7FTX 0x0 RW

FTX flushes the transmit circuitry (FIFO, fsm). The configuration of the

I²C node (register setting) is not affected by the flushing operation. The

flushing operation is performed on modules working on different clock

domains (system and I²C clocks) and needs several system clock cycles

before being completed. Upon completion, the I²C node (internal logic)

clears this bit. The application must not access the Tx FIFO during the

flushing operation and should poll on this bit waiting for completion.

0: Flush operation is completed (I2C controller clears the bit).

1: Flush operation is started and in progress (set by application).

8 FRX 0x0 RW

FRX flushes the receive circuitry (FIFO, fsm).The configuration of the

I²C node (register setting) is not affected by the flushing operation. The

flushing operation is performed on modules working on different clock

domains (system and I²C clocks) and needs several system clock cycles

before to be completed. Upon completion, the I²C node (internal logic)

clears this bit. The application must not access the Rx FIFO during the

flushing operation and should poll on this bit waiting for the completion.

0: Flush operation is completed (I2C controller clears the bit).

1: Flush operation is started and in progress (set by application).

9 DMA_TX_EN 0x0 RW

Enables the DMA TX interface.

0: Idle state, the DMA TX interface is disabled.

1: Run state, the DMA TX interface is enabled.

On the completion of the DMA transfer, the DMA TX interface is

automatically turned off clearing this bit when the end of transfer signal

coming from the DMA is raised. DMA_TX_EN and DMA_RX_EN must not

enabled at the same time.

10 DMA_RX_EN 0x0 RW

Enables the DMA RX interface.

0: Idle state, the DMA RX interface is disabled.

1: Run state, the DMA RX interface is enabled.

On the completion of the DMA transfer, the DMA RX interface is

automatically turned off clearing this bit when the end of transfer signal

coming from the DMA is raised. DMA_TX_EN and DMA_RX_EN must not

enabled at the same time.

12:11 RESERVED 0x0 RW RESERVED

14:13 FON 0x0 RW Filtering on sets the digital filters on the SDA, SCL line, according to the

I²C bus requirements, when standard open-drain pads are used:

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Bit Field name Reset RW Description

00b: No digital filters are inserted.

01b: Digital filters (filter 1 ck wide spikes) are inserted.

10b: Digital filters (filter 2 ck wide spikes) are inserted.

11b: Digital filters (filter 4 ck wide spikes) are inserted.

15 FS_1 0x0 RW

Force stop enable bit. When set to 1b, the STOP condition is generated.

0: Force stop disabled.

1: Enable force stop.

31:16 RESERVED 0x0 RW RESERVED

Table 100. I2C - SCR register description: address offset I2CX_BASE_ADDR+0x04

Bit Field name Reset RW Description

6:0 SA7 0x55 RW Slave address 7-bit. SA7 includes the slave address 7-bit or the LSB bits of

the slave address 10-bit

9:7 ESA10 0x0 RW Extended slave address 10-bit. ESA10 includes the extension (MSB bits) to

the SA7 register field in case of slave addressing mode set to 10-bit

15:10 RESERVED 0x0 RW RESERVED

31:16 SLSU 0xF RW

Slave data setup time. SLSU defines the data setup time after SCL clock

stretching in terms of i2c_clk cycles. Data setup time is actually equal to

SLSU-1 clock cycles. The typical values for i2c_clk of 16 MHz are SLSU = 5

in standard mode and SLSU = 3 in fast modes.

Table 101. I2C2 - MCR register description: address offset I2CX_BASE_ADDR+0x0C

Bit Field name Reset RW Description

0 OP 0x0 RW

Operation

0: Indicates a master write operation.

1: Indicates a master read operation.

7:1 A7 0x0 RW Address. Includes the 7-bit address or the LSB bits of the10-bit address

used to initiate the current transaction

10:8 EA10 0x0 RW Extended address. Includes the extension (MSB bits) of the field A7 used to

initiate the current transaction

11 SB 0x0 RW

Start byte:

0: The start byte procedure is not applied to the current transaction.

1: The start byte procedure is prefixed to the current transaction.

13:12 AM 0x0 RW

Address type:

00b: The transaction is initiated by a general call command. In this case the

fields OP

, A7, EA10 are "don't care".

01b: The transaction is initiated by the 7-bit address included in the A7 field.

10b: The transaction is initiated by the 10-bit address included in the EA10

and A7 fields.

14 P 0x0 RW

Stop condition:

0: The current transaction is not terminated by a STOP condition. A

repeated START condition is generated on the next operation which is

required to avoid to stall the I²C line.

1: The current transaction is terminated by a STOP condition.

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Bit Field name Reset RW Description

25:15 LENGTH 0x0 RW

Transaction length. Defines the length, in terms of the number of bytes to be

transmitted (MW) or received (MR). In case of write operation, the payload

is stored in the Tx FIFO. A transaction can be larger than the Tx FIFO size.

In case of read operation the length refers to the number of bytes to be

received before generating a not-acknowledge response. A transaction can

be larger than the Rx FIFO size. The I²C clock line is stretched low until the

data in Rx FIFO are consumed.

31:26 RESERVED 0x0 RW RESERVED

Table 102. I2C - TFR register description: address offset I2CX_BASE_ADDR+0x10

Bit Field name Reset RW Description

7:0 TDATA 0x0 RW

Transmission data. TDATA contains the payload related to a master write or

read-from-slave operation to be written in the Tx FIFO. TDATA(0) is the first

LSB bit transmitted over the I²C line.

In case of master write operation, the Tx FIFO shall be preloaded otherwise

the I²C controller cannot start the operation until data are available.

In case of read-from-slave operation, when the slave is addressed, the

interrupt RISR:RFSR bit is asserted and the CPU shall download the data

in the FIFO. If the FIFO is empty and the I²C master is still requiring data,

a new request (RISR:RFSE interrupt bit) is asserted to require additional

data to the CPU. The slave controller stretches the I²C clock line when

no data are available for transmission. Since the Tx FIFO could contain

some pending data related to the previous transfer (the transfer length may

be unknown to the slave controller), the Tx FIFO is self-flushed before

asserting the I2C_RISR:RFSR bit. Upon completion of the read-from-slave

operation the interrupt bit I2C_RISR:STD is asserted and the related status

of the operation is stored in the I2C_SR register. In CPU mode, the FIFO

management is based on the assertion of the interrupt bit RISR:TXFNE,

related to the nearly-empty threshold.

In DMA mode, the single/burst requests are automatically executed based

on the number of entries available in the TX FIFO and the related

destination burst size programmed in the I2C_DMAR:DBSIZE_TX register

field. The DMA requests are terminated at the end of the I²C read operation

(notacknowledge received by the master) by a dummy last single/burst

request.

31:8 RESERVED 0x0 RW RESERVED

Table 103. I2C - SR register description: address offset I2CX_BASE_ADDR+0x14

Bit Field name Reset RW Description

1:0 OP 0x0 R

Operation:

00b: MW: master write operation.

01b: MR: master read operation.

10b: WTS: write-to-slave operation.

11b: RFS: read-from-slave operation.

3:2 STATUS 0x0 R

Controller status. Valid for the operations MW, MR, WTS RFS:

00b: NOP: No operation is in progress.

01b: ON_GOING: An operation is ongoing.

10b: OK: The operation (OP field) has been completed successfully.

11b: ABORT: The operation (OP field) has been aborted due to the

occurrence of the event described in the CAUSE field.

6:4 CAUSE 0x0 R Abort cause. This field is valid only when the STATUS field contains the

ABORT tag. Others: RESERVED.

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Bit Field name Reset RW Description

000b: NACK_ADDR: The master receives a not-acknowledge after the

transmission of the address. Valid for the operation MW, MR.

001b: NACK_DATA: The master receives a not-acknowledge during the

data phase of a MW operation. Valid for the operation MW.

011b: ARB_LOST: The master loses the arbitration during a MW or MR

operation. Valid for the operation MW, MR.

100b: BERR_START: Slave restarts, a START Condition occurs while the

byte transfer is not terminated.

101b: BERR_STOP: Slave Reset, a STOP Condition while the byte transfer

is not terminated.

110b: OVFL: The slave receives a frame related to the WTS operation

longer than the maximum size = 2047 bytes. In this case the slave device

returns a NACK to complete the data transfer. Valid for WTS operation

8:7 TYPE 0x0 R

Receive type. Valid only for the operation WTS:

00b: FRAME: The slave has received a normal frame.

01b: GCALL: The slave has received a general call. If the it I2C_CR:SGCM

is set to 1, the general call is directly executed without software intervention

and only the control code word is reported in FIFO (LENGTH =0).

10b: HW_GCALL: The slave has received a hardware general call.

19:9 LENGTH 0x0 R

Transfer length. For an MR, WTS operation the LENGTH field defines the

actual size of the subsequent payload, in terms of number of bytes. For an

MW, RFS operation the LENGTH field defines the actual number of bytes

transferred by the master/slave device. For a WTS operation if the transfer

length exceeds 2047 bytes, the operation is stopped by the slave returning

a NACK handshake and the flag OVFL is set. For an RFS operation if the

transfer length exceeds 2047 bytes, the operation continues normally but

the LENGTH field is reset to 0.

28:

20 RESERVED 0x0 R RESERVED

29 DUALF 0x0 R

Dual flag (slave mode):

0: Received address matched with slave address (SA7).

1: Received address matched with dual slave address (DSA7).

Cleared by hardware after a stop condition or repeated Start condition, bus

error or when PE=0.

31:30 RESERVED 0x0 R RESERVED

Table 104. I2C - RFR register description: address offset I2CX_BASE_ADDR+0x18

Bit Field name Reset RW Description

7:0 RDATA 0x0 R

Receive data. RDATA contains the received payload, related to a master

read or write-to-slave operation, to be read from the Rx FIFO. The

RDATA(0) is the first LSB bit received over the I2C line. In case the FIFO is

full, the I2C controller stretches automatically the I2C clock line until a new

entry is available.

For a write-to-slave operation, when the slave is addressed, the interrupt

I2C_RISR:WTSR bit is asserted for notification to the CPU. In CPU mode

the FIFO management shall be based on the assertion of the interrupt bit

I2C_RISR:RXFNF, related to the nearly-full threshold.

In DMA mode, the single requests are automatically executed based on the

number of entries contained in the Rx FIFO.

31:8 RESERVED 0x0 R RESERVED

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Table 105. I2C - TFTR register description: address offset I2CX_BASE_ADDR+0x1C

Bit Field name Reset RW Description

9:0 THRESH_TX 0x0 RW

Threshold TX, contains the threshold value, in terms of number of bytes, of

the Tx FIFO.

When the number of entries of the Tx FIFO is less or equal than the

threshold value, the interrupt bit I2C_RISR:TXFNE is set in order to

request the loading of data to the application.

31:10 RESERVED 0x0 RW RESERVED

Table 106. I2C - RFTR register description: address offset I2CX_BASE_ADDR+0x20

Bit Field name Reset RW Description

9:0 THRESH_RX 0x0 RW

Threshold RX, contains the threshold value, in terms of number of bytes,

of the Rx FIFO.

When the number of entries of the RX FIFO is greater than or equal to

the threshold value, the interrupt bit RISR:RXFNF is set in order to request

the download of received data to the application. The application shall

download the received data based on the threshold. (RISR:RXFNF).

31:10 RESERVED 0x0 RW RESERVED

Table 107. I2C - DMAR register description: address offset I2CX_BASE_ADDR+0x24

Bit Field name Reset RW Description

7:0 RESERVED 0x0 RW RESERVED

10:8 DBSIZE_TX 0x0 RW

Destination burst size. This register field is valid only if the BURST_TX bit

is set to '1'. If burst size is smaller than the transaction length, only single

request are generated.

11 BURST_TX 0x0 RW

Defines the type of DMA request generated by the DMA TX interface.

0: Single request mode. Transfers a single data (one byte) in the TX FIFO.

1: Burst request mode. Transfers a programmed burst of data according to

DBSIZE_TX field.

When the burst mode is programmed, the DMA transfer can be completed

by one or more single requests as required.

31:12 RESERVED 0x0 RW RESERVED

Table 108. I2C - BRCR register description: address offset I2CX_BASE_ADDR+0x28

Bit Field name Reset RW Description

15:0 BRCNT 0x8 RW

Baud rate counter. BRCNT defines the counter value used to set up the I2C

baud rate in standard and fast mode, when the peripheral is operating in

master mode.

31:16 RESERVED 0x0 RW RESERVED

Table 109. I2C - IMSCR register description: address offset I2CX_BASE_ADDR+0x2C

Bit Field name Reset RW Description

0 TXFEM 0x0 RW

TX FIFO empty mask. TXFEM enables the interrupt bit TXFE:

0: TXFE interrupt is disabled.

1: TXFE interrupt is enabled.

1 TXFNEM 0x0 RW TX FIFO nearly empty mask. TXFNEM enables the interrupt bit TXFNE:

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Bit Field name Reset RW Description

0: TXFNE interrupt is disabled.

1: TXFNE interrupt is enabled.

2 TXFFM 0x0 RW

TX FIFO full mask. TXFFM enables the interrupt bit TXFF:

0: TXFF interrupt is disabled.

1: TXFF interrupt is enabled.

3 TXFOVRM 0x0 RW

TX FIFO overrun mask. TXOVRM enables the interrupt bit TXOVR:

0: TXOVR interrupt is disabled.

1: TXOVR interrupt is enabled.

4 RXFEM 0x0 RW

RX FIFO empty mask. RXFEM enables the interrupt bit RXFE:

0: RXFE interrupt is disabled.

1: RXFE interrupt is enabled.

5 RXFNFM 0x0 RW

RX FIFO nearly full mask. RXNFM enables the interrupt bit RXNF:

0: RXNF interrupt is disabled.

1: RXNF interrupt is enabled

6 RXFFM 0x0 RW

RX FIFO full mask. RXFFM enables the interrupt bit RXFF:

0: RXFF interrupt is disabled.

1: RXFF interrupt is enabled.

15:7 RESERVED 0x0 RW RESERVED

16 RFSRM 0x0 RW

Read-from-slave request mask. RFSRM enables the interrupt bit RFSR:

0: RFSR interrupt is disabled.

1: RFSR interrupt is enabled.

17 RFSEM 0x0 RW

Read-from-slave empty mask. RFSEM enables the interrupt bit RFSE:

0: RFSE interrupt is disabled.

1: RFSE interrupt is enabled.

18 WTSRM 0x0 RW

Write-to-slave request mask. WTSRM enables the interrupt bit WTSR:

0: WTSR interrupt is disabled.

1: WTSR interrupt is enabled.

19 MTDM 0x0 RW

Master transaction done mask. MTDM enables the interrupt bit MTD:

0: MTD interrupt is disabled.

1: MTD interrupt is enabled.

20 STDM 0x0 RW

Slave transaction done mask. STDM enables the interrupt bit STD:

0: STDM interrupt is disabled.

1: STDM interrupt is enabled.

23:21 RESERVED 0x0 RW RESERVED

24 MALM 0x0 RW

Master arbitration lost mask. MALM enables the interrupt bit MAL:

0: MAL interrupt is disabled.

1: MAL interrupt is enabled.

25 BERRM 0x0 RW

Bus error mask. BERRM enables the interrupt bit BERR:

0: BERR interrupt is disabled.

1: BERR interrupt is enabled.

27:26 RESERVED 0x0 RW RESERVED

28 MTDWSM 0x0 RW

Master transaction done without stop mask. MTDWSM enables the interrupt

bit MTDWS:

0: MTDWS interrupt is disabled.

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Bit Field name Reset RW Description

1: MTDWS interrupt is enabled.

31:29 RESERVED 0x0 RW RESERVED

Table 110. I2C - RISR register description: address offset I2CX_BASE_ADDR+0x30

Bit Field name Reset RW Description

0 TXFE 0x1 R

TX FIFO empty. TXFE is set when TX FIFO is empty. This bit is self-cleared

by writing in TX FIFO.

0: TX FIFO is not empty.

1: TX FIFO is empty.

1 TXFNE 0x1 R

TX FIFO nearly empty. TXFNE is set when the number of entries in TX

FIFO is less than or equal to the threshold value programmed in the

I2C_TFTR:THRESHOLD_TX register. It is self-cleared when the threshold

level is over the programmed threshold.

0: Number of entries in TX FIFO greater than the TFTR:THRESHOLD_TX

1: Number of entries in TX FIFO less than or equal to the

TFTR:THRESHOLD_TX register.

2 TXFF 0x0 R

TX FIFO full. TXFF is set when a full condition occurs in TX FIFO. This bit is

self-cleared when the TX FIFO is not full:

0: TX FIFO is not full.

1: TX FIFO is full.

3 TXFOVR 0x0 R

TX FIFO overrun. TXFOVR is set when a write operation in TX FIFO is

performed and TX FIFO is full. The application must avoid an overflow

condition by a proper data flow control. Anyway in case of overrun, the

application shall flush the transmitter (CR:FTX bit to set) because the TX

FIFO content is corrupted (at least one word has been lost in FIFO). This

interrupt is cleared by setting the related bit of the ICR register:

0: No overrun condition occurred in TX FIFO.

1: Overrun condition occurred in TX FIFO.

4 RXFE 0x1 R

RX FIFO empty. RXFE is set when the RX FIFO is empty. This bit is

self-cleared when the slave RX FIFO is not empty:

0: RX FIFO is not empty.

1: RX FIFO is empty.

5 RXFNF 0x0 R

RX FIFO nearly full. RXFNF is set when the number of entries in RX

FIFO is greater than or equal to the threshold value programmed in the

RFTR:THRESHOLD_RX register. Its self-cleared when the threshold level

is under the programmed threshold:

0: Number of entries in the RX FIFO less than the RFTR:THRESHOLD_RX

1: Number of entries in the RX FIFO greater than or equal to the

RFTR:THRESHOLD_RX register.

6 RXFF 0x0 R

RX FIFO full. RXFF is set when a full condition occurs in RX FIFO. This bit

is self-cleared when the data are read from the RX FIFO.

0: RX FIFO is not full.

1: RX FIFO is full.

15:7 RESERVED 0x0 R RESERVED

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Bit Field name Reset RW Description

16 RFSR 0x0 R

Read-from-slave request. RFSR is set when a read-from-slave

"Slavetransmitter" request is received (I²C slave is addressed) from the

I²C line. On the assertion of this interrupt the TX FIFO is flushed (pending

data are cleared) and the CPU shall put the data in TX FIFO. This bit is

self-cleared by writing data in FIFO. In case the FIFO is empty before the

completion of the read operation, the RISR:RFSE interrupt bit is set.This

interrupt is cleared by setting the related bit of the ICR register.

0: Read-from-slave request has been served.

1: Read-from-slave request is pending.

17 RFSE 0x0 R

Read-from-slave empty. RFSE is set when a read-from-slave operation is in

progress and TX FIFO is empty. On the assertion of this interrupt, the CPU

shall download in TX FIFO the data required for the slave operation. This

bit is self-cleared by writing in TX FIFO. At the end of the read-from-slave

operation this bit is cleared although the TX FIFO is empty.

0: TX FIFO is not empty.

1: TX FIFO is empty with the read-from-slave operation in progress.

18 WTSR 0x0 R

Write-to-slave request. WTSR is set when a write-to-slave operation is

received (I2C slave is addressed) from the I2C line. This notification can

be used by the application to program the DMA descriptor when required.

This interrupt is cleared by setting the related bit of the ICR register:

0: No write-to-slave request pending.

1: Write-to-slave request is pending.

19 MTD 0x0 R

Master transaction done. MTD is set when a master operation (master write

or master read) has been executed after a stop condition. The application

shall read the related transaction status (SR register), the pending data in

the RX FIFO (only for a master read operation) and clear this interrupt

(transaction acknowledgment). A subsequent master operation can be

issued (writing the MCR register) after the clearing of this interrupt. A

subsequent slave operation will be notified (RISR:WTSR and RISR:RFSR

interrupt bits assertion) after clearing this interrupt, meanwhile the I²C clock

line is stretched low. This interrupt is cleared by setting the related bit of the

ICR register.

0: Master transaction acknowledged.

1: Master transaction done (ready for acknowledgment).

20 STD 0x0 R

Slave transaction done. STD is set when a slave operation (write-to-

slave or read-from-slave) has been executed. The application shall read

the related transaction status (SR register), the pending data in the

RX FIFO (only for a write-to-slave operation) and clear this interrupt

(transaction acknowledgment). A subsequent slave operation will be notified

(RISR:WTSR and RISR:RFSR interrupt bits assertion) after clearing this

interrupt, meanwhile the I2C clock line will be stretched low. A subsequent

master operation can be issued (by writing the MCR register) after clearing

this interrupt. This interrupt is cleared by setting the related bit of the ICR

0: Slave transaction acknowledged.

1: Slave transaction done (ready for acknowledgment).

23:21 RESERVED 0x0 R RESERVED

24 MAL 0x0 R

Master arbitration lost. MAL is set when the master loses the arbitration.

The status code word in the SR contains a specific error tag (CAUSE

field) for this error condition. A collision occurs when 2 stations transmit

simultaneously 2 opposite values on the serial line. The station that is

pulling up the line, identifies the collision reading a 0 value on the sda_in

signal, stops the transmission, leaves the bus and waits for the idle

state (STOP condition received) on the bus line before retrying the same

transaction. The station which transmits the first unique zero wins the bus

arbitration. This interrupt is cleared by setting the related bit of the ICR

0: No master arbitration lost.

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Bit Field name Reset RW Description

1: Master arbitration lost.

25 BERR 0x0 R

Bus Error. BERR is set when an unexpected Start/Stop condition occurs

during a transaction. The related actions are different, depending on the

type of operation in progress.The status code word in the SR contains a

specific error tag (CAUSE field) for this error condition. This interrupt is

cleared by setting the related bit of the ICR register.

0: No bus error detection.

1: Bus error detection.

27:26 RESERVED 0x0 R RESERVED

28 MTDWS 0x0 R

Master transaction done without stop. MTDWS is set when a master

operation (write or read) has been executed and a stop (MCR:P field)

is not programmed. The application shall read the related transaction

status (SR register), the pending data in the RX FIFO (only for a master

read operation) and clear this interrupt (transaction acknowledgment). A

subsequent master operation can be issued (by writing the MCR register)

after clearing this interrupt. A subsequent slave operation will be notified

(RISR:WTSR and RISR:RFSR interrupt bits assertion) after clearing this

interrupt, meanwhile the I²C clock line will be stretched low. This interrupt is

cleared by setting the related bit of the ICR register:

0: Master transaction acknowledged.

1: Master transaction done (ready for acknowledgment) and stop is not

applied into the I²C bus.

31:29 RESERVED 0x0 R RESERVED

Table 111. I2C - MISR register description: address offset I2CX_BASE_ADDR+0x34

Bit Field name Reset RW Description

0 TXFEMIS 0x0 R

TX FIFO empty masked interrupt status.

0: TX FIFO is not empty.

1: TX FIFO is empty.

1 TXFNEMIS 0x0 R

TX FIFO nearly empty masked interrupt status.

0: Number of entries in TX FIFO greater than the TFTR:THRESHOLD_TX

1: Number of entries in TX FIFO less than or equal to the

TFTR:THRESHOLD_TX register.

2 TXFFMIS 0x0 R

Tx FIFO full masked interrupt status.

0: TX FIFO is not full.

1: TX FIFO is full.

3 TXFOVRMIS 0x0 R

Tx FIFO overrun masked interrupt status.

0: No overrun condition occurred in TX FIFO.

1: Overrun condition occurred in TX FIFO.

4 RXFEMIS 0x0 R

RX FIFO empty masked interrupt status.

0: RX FIFO is not empty.

1: RX FIFO is empty.

5 RXFNFMIS 0x0 R

RX FIFO nearly full masked interrupt status.

0: Number of entries in the RX FIFO less than the RFTR:THRESHOLD_RX

1: Number of entries in the RX FIFO greater than or equal to the

RFTR:THRESHOLD_RX register.

6 RXFFMIS 0x0 R RX FIFO full masked interrupt status.

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Bit Field name Reset RW Description

0: RX FIFO is not full.

1: RX FIFO is full.

15:7 RESERVED 0x0 R RESERVED

16 RFSRMIS 0x0 R

Read-from-slave request masked interrupt status.

0: Read-from-slave request has been served.

1: Read-from-slave request is pending.

17 RFSEMIS 0x0 R

Read-from-slave empty masked interrupt status.

0: TX FIFO is not empty.

1: TX FIFO is empty with the read-from-slave operation in progress.

18 WTSRMIS 0x0 R

Write-to-slave request masked interrupt status.

0: No write-to-slave request pending.

1: Write-to-slave request is pending.

19 MTDMIS 0x0 R

Master transaction done masked interrupt status.

0: Master transaction acknowledged.

1: Master transaction done (ready for acknowledgment).

20 STDMIS 0x0 R

Slave transaction done masked interrupt status.

0: Slave transaction acknowledged.

1: Slave transaction done (ready for acknowledgment).

23:21 RESERVED 0x0 R RESERVED

24 MALMIS 0x0 R

Master arbitration lost masked interrupt status.

0: No master arbitration lost.

1: Master arbitration lost.

25 BERRMIS 0x0 R

Bus error masked interrupt status.

0: No bus error detection.

1: Bus error detection.

27:26 RESERVED 0x0 R RESERVED

28 MTDWSMIS 0x0 R

Master transaction done without stop masked interrupt status.

0: Master transaction acknowledged.

1: Master transaction done (ready for acknowledgment) and stop is not

applied into the I²C bus.

31:29 RESERVED 0x0 R RESERVED

Table 112. I2C - ICR register description: address offset I2CX_BASE_ADDR+0x38

Bit Field name Reset RW Description

2:0 RESERVED 0x0 RW RESERVED

3 TXFOVRIC 0x0 RW

Tx FIFO overrun interrupt clear.

0: Has no effect.

1: Clears interrupt pending.

15:4 RESERVED 0x0 RW RESERVED

16 RFSRIC 0x0 RW

Read-from-Slave request interrupt clear.

0: Has no effect.

1: Clears interrupt pending.

17 RFSEIC 0x0 RW Read-from-slave empty interrupt clear.

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Bit Field name Reset RW Description

0: Has no effect.

1: Clears interrupt pending.

18 WTSRIC 0x0 RW

Write-to-slave request interrupt clear.

0: Has no effect.

1: Clears interrupt pending.

19 MTDIC 0x0 RW

Master transaction done interrupt clear.

0: Has no effect.

1: Clears interrupt pending.

20 STDIC 0x0 RW

Slave transaction done interrupt clear.

0: Has no effect.

1: Clears interrupt pending.

23:21 RESERVED 0x0 RW RESERVED

24 MALIC 0x0 RW

Master arbitration lost interrupt clear.

0: Has no effect.

1: Clears interrupt pending.

25 BERRIC 0x0 RW

Bus error interrupt clear.

0: Has no effect.

1: Clears interrupt pending.

27:26 RESERVED 0x0 RW RESERVED

28 MTDWSIC 0x0 RW

Master transaction done without stop interrupt clear.

0: Has no effect.

1: Clears interrupt pending.

31:29 RESERVED 0x0 RW RESERVED

Table 113. I2C - THDDAT register description: address offset I2CX_BASE_ADDR+0x4C

Bit Field name Reset RW Description

8:0 THDDAT 0x14 RW

Hold time data value. In master or slave mode, when the I2C controller

detects a falling edge in the SCL line, the counter, which is loaded by the

THDDAT, is launched. Once the THDDAT value is reached, the data is

transferred.

31:9 RESERVED 0x0 RW RESERVED

Table 114. I2C - THDSTA_FST_STD register description: address offset I2CX_BASE_ADDR+0x50

Bit Field name Reset RW Description

8:0 THDSTA_STD 0xE2 RW

Hold time start condition value for standard mode. When the start

condition is asserted, the decimeter loads the value of THDSTA_STD for

standard mode, once the THDSTA_STD value is reached, the SCL line

asserts low.

15:9 RESERVED 0x0 RW RESERVED

24:16 THDSTA_FST 0x3F RW

Hold time start condition value for fast mode. When the start condition is

asserted, the decimeter loads the value of THDSTA_FST for fast mode,

once the THDSTA_FST value is reached, the SCL line assert slow.

31:25 RESERVED 0x0 RW RESERVED

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Table 115. I2C - TSUSTA_FST_STD register description: address offset I2CX_BASE_ADDR+0x58

Bit Field name Reset RW Description

8:0 TSUSTA_STD 0xE2 RW

Setup time start condition value for standard mode. After a non-stop on

the SCL line the decimeter loads the value of TSUSTA_STD according

to standard mode. Once the counter is expired, the start condition is

generated.

15:9 RESERVED 0x0 RW RESERVED

24:16 TSUSTA_FST 0x1D RW

Set-up time start condition value for fast mode. After a non-stop on the

SCL line the decimeter loads the value of TSUSTA_FST according to fast

mode. Once the counter is expired the start condition is generated.

31:25 RESERVED 0x0 RW RESERVED

Note: All RESERVED fields inside registers must always be written with their default value.

3.11 Flash controller

3.11.1 Flash controller introduction

The BlueNRG-2 integrates a Flash controller to interface the embedded Flash memory.

Main features are:

•Sector erase and mass erase

•256 kbyte Flash memory: 128 pages of 8 rows with 64 words each

• Flash programming

• Mass read

• Enable readout protection

• 32-bit read access

• 32-bit write access in single write and 4x32-bit in burst write (reduce programming time by 2)

3.11.2 Flash controller functional description

The BlueNRG-2 embeds up to 256 KB (65536 x 32-bit) of internal Flash memory. A Flash interface implements

instruction access and data access based on the AHB protocol. It implements the logic necessary to carry out the

Flash memory operations (Program/Erase) controlled through the Flash registers.

Writing to Flash only allows clearing bits from ‘1’ to ‘0’. This means any write from ‘0’ to ‘1’ implies erasing before

performing a write.

Flash memory is composed of 128 pages containing 8 rows of 64 words (128 x 8 x 64 = 65536 words). Each word

is 32-bit = 4 bytes long which means 256 kB of Flash.

The address inside the ADDRESS register is built as follows:

ADDRESS[15:0] = XADR[9:0] & YADR[5:0] with:

• XADR[9:3] = page address

• XADR[2:0] = row address

• YADR[5:0] = word address (one word = four bytes)

Note: One specific address can be written only twice between two erase actions even if each writing only clears bits.

Note: The Flash data retention is greater than 10 years at 85 °C. The Flash is rated to have a Flash cycling of 10.000

write/erase cycles.

3.11.2.1 Reading Flash memory

To read one single word of the flash, just read it as if RAM memory: read the desired flash address and get read

data on the bus.

3.11.2.2 Erasing Flash

The Flash controller allows erasing one page or the full main Flash.

ERASE sequence (erase one page):

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1. Write the page address to be erased by writing in the ADDRESS register the following value:

a. ADDRESS[15:9] = XADR[9:3] = page address to erase

b. ADDRESS[8:0] = 9’b0 (row and word addresses at zero).

2. Write the ERASE command (0x11) in the COMMAND register.

3. Wait for the CMDSTART flag in the IRQSTAT register (polling mode or interrupt mode) indicating command

is taken into account and under execution.

4. Clear the CMDSTART flag by writing CMDSTART to ‘1’ in the IRQSTAT register.

5. Wait for the CMDDONE flag in the IRQSTAT register (polling mode or interrupt mode) indicating that the

command is completed.

6. Clear the CMDDONE flag by writing CMDDONE to ‘1’ in the IRQSTAT register.

After this command, the erased page contains only bits set to ‘1’.

MASSERASE sequence (erase completely main flash):

1. Write the MASSERASE command (0x22) in the COMMAND register.

2. Wait for the CMDSTART flag in the IRQSTAT register (polling mode or interrupt mode) indicating that the

command has been taken into account and is under execution.

3. Clear the CMDSTART flag by writing CMDSTART to ‘1’ in the IRQSTAT register.

4. Wait for the CMDDONE flag in the IRQSTAT register (polling mode or interrupt mode) indicating that the

command is completed.

5. Clear the CMDDONE flag by writing CMDDONE to ‘1’ in the IRQSTAT register.

After this command, the full main Flash contains only bits set to ‘1’.

3.11.2.3 Write function examples

The Flash Controller allows writing one word (WRITE), up to 4 words (BURSTWRITE) or the full main Flash

memory (with a single fixed word).

Note: As a write can only program to ‘0’ on bits already set to ‘1’, it is necessary to erase the page and request

that the bits be set to ‘1’ (instead of ‘0’) in order to re-write to ‘0’.

WRITE sequence:

1. Indicate the location to write by filling the ADDRESS register with the targeted address (page, row and word

number)

2. Write the value to program in the DATA0 register.

3. Write the WRITE command (0x33) in the COMMAND register.

4. Wait for the CMDSTART flag in the IRQSTAT register (polling mode or interrupt mode) indicating that the

command has been taken into account and is under execution.

5. Clear the CMDSTART flag by writing CMDSTART to ‘1’ in the IRQSTAT register.

6. Wait for the CMDDONE flag in the IRQSTAT register (polling mode or interrupt mode) indicating that the

command is completed.

7. Clear the CMDDONE flag by writing CMDDONE to ‘1’ in the IRQSTAT register.

BURSTWRITE sequence:

1. Indicate the location to write by filling the ADDRESS register with the targeted address of the first data to

write (page, row and word number). DATA0 will be written and ADDRESS, DATA1 at ADDRESS+1 and so

on. (Write the values to program in the DATA0-3 registers. To write less than four words, write 0xFFFFFFFF

in the unused DATA1-3 registers.)

2. Write the BURSTWRITE command (0xCC) in the COMMAND register.

3. Wait for the CMDSTART flag in the IRQSTAT register (polling mode or interrupt mode) indicating that the

command has been taken into account and is under execution.

4. Clear the CMDSTART flag by writing CMDSTART to ‘1’ in the IRQSTAT register.

5. Wait for the CMDDONE flag in the IRQSTAT register (polling mode or interrupt mode) indicating that the

command is completed.

6. Clear the CMDDONE flag by writing CMDDONE to ‘1’ in the IRQSTAT register.

3.11.2.4 Flash readout protection

It is possible to protect flash memory from unwanted access while in debug mode, this is normally used to avoid

copy or reverse engineering of a deployed application in the market.

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If the readout protection mechanism is activated, as soon as Cortex-M0 is halted, any access to Flash memory

will return a fixed 0x0 value and generate an AHB error if a debugger tries to read it.

Note that RAM memory debug accesses are also disabled by this lock protection.

Enabling readout protection:

1. Program a secret 64 bit sequence in the last two word address of the user flash. The secret 64 bit sequence

can be anything different from 0xFFFFFFFF, 0xFFFFFFFF.

Disable readout protection:

1. Perform a mass erase of the user flash

3.11.2.5 Flash command list

The valid command values list for the COMMAND register is reported in the table below.

Table 116. Flash commands

Command name Description Value

ERASE Erase page defined by register ADDRESS 0x11

MASSERASE Mass erase (Flash is completely erased) 0x22

WRITE Program one location (defined by registers DATA and ADDRESS) 0x33

BURSTWRITE Burst write operation 0xCC

3.11.2.6 Flash interface timing characteristics

Table 117. Flash interface timing

Description Max. Unit

Page erase time 21.5 ms

Mass erase time 21.5 ms

Program time WRITE 44 µs

Program time BURSTWRITE 1 word (1) 44 µs

Program time BURSTWRITE 2 words(1) 65 µs

Program time BURSTWRITE 3 words(1) 86 µs

Program time BURSTWRITE 4 words(1) 107 µs

1. Burst write procedure skips the 0xFFFF_FFFF word

3.11.3 Flash controller registers

Flash controller peripheral base address (FLASH_BASE_ADDR) 0x40100000.

Table 118. FLASH controller registers

Address offset Name RW Reset Description

0x00 COMMAND RW 0x00000000 Commands for the module

0x04 CONFIG RW 0x00000000 Configure the wrapper

0x08 IRQSTAT RW 0x00000000 Flash status interrupt (masked). Refer to the detailed description

below.

0x0C IRQMASK RW 0x0000003F Mask for interrupts. Refer to the detailed description below.

0x10 IRQRAW RW 0x00000000 Status interrupts (unmasked). Refer to the detailed description

below.

0x14 SIZE R 0x0000FFFF Indicates the size of the Flash

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Address offset Name RW Reset Description

0x18 ADDRESS RW 0x00000000 Address for programming Flash, will auto-increment

0x24 RESERVED R 0xFFFFFFFF RESERVED

0x28 RESERVED RW 0x0B061515 RESERVED

0x2C RESERVED RW 0x0B156506 RESERVED

0x30 RESERVED RW 0x00000011 RESERVED

0x40 DATA0 RW 0xFFFFFFFF Program cycle data

0x44 DATA1 RW 0xFFFFFFFF Program cycle data

0x48 DATA2 RW 0xFFFFFFFF Program cycle data

0x4C DATA3 RW 0xFFFFFFFF Program cycle data

Table 119. FLASH – COMMAND register description: address offset FLASH_BASE_ADDR+0x00

Bit Field name Reset RW Description

31:0 COMMAND 0x00000000 RW Command for the module.

Table 120. FLASH – CONFIG register description: address offset FLASH_BASE_ADDR+0x04

Bit Field name Reset RW Description

0 RESERVED 0 RW RESERVED

1 REMAP 0 RW Remaps the interrupt vector table in RAM

2 RESERVED 0 RW RESERVED

3 PREMAP 0 RW Remaps the interrupt vector table in FLASH

31:4 RESERVED 0 RW RESERVED

Table 121. FLASH - IRQSTAT register description: address offset FLASH_BASE_ADDR+0x08

Bit Field name Reset RW Description

0 CMDDONE 0x0 RW Command is done. 1: clear the interrupt pending bit.

1 CMDSTART 0x0 RW Command is started.1: clear the interrupt pending bit.

2 CMDERR 0x0 RW Command written while BUSY. 1: clear the interrupt pending bit.

3 ILLCMD 0x0 RW Illegal command written. 1: clear the interrupt pending bit.

4 READOK 0x0 RW Mass read was OK. 1: clear the interrupt pending bit.

5 FLNREADY 0x0 RW Flash not ready (sleep). 1: clear the interrupt pending bit.

31:6 RESERVED 0x0 RW RESERVED

Table 122. FLASH - IRQMASK register description: address offset FLASH_BASE_ADDR+0x0C

Bit Field name Reset RW Description

0 CMDDONE 0x1 RW Command is done.

1 CMDSTART 0x1 RW Command is started.

2 CMDERR 0x1 RW Command written while BUSY

3 ILLCMD 0x1 RW Illegal command written

4 READOK 0x1 RW Mass read was OK.

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Bit Field name Reset RW Description

5 FLNREADY 0x1 RW Flash not ready (sleep).

31:6 RESERVED 0x0 RW RESERVED

Table 123. FLASH - IRQRAW register description: address offset FLASH_BASE_ADDR+0x10

Bit Field name Reset RW Description

0 CMDDONE 0x0 RW Command is done.

1 CMDSTART 0x0 RW Command is started.

2 CMDERR 0x0 RW Command written while BUSY

3 ILLCMD 0x0 RW Illegal command written

4 READOK 0x0 RW Mass read was OK.

5 FLNREADY 0x0 RW Flash not ready (sleep).

31:6 RESERVED 0x0 RW RESERVED

Table 124. FLASH – SIZE register description: address offset FLASH_BASE_ADDR+0x14

Bit Field name Reset RW Description

15:0 SIZE 0xFFFF R Indicates the size of the flash. 0xFFFF: 256 kB of flash

31:16 RESERVED 0x0000 R RESERVED

Table 125. FLASH – ADDRESS register description: address offset FLASH_BASE_ADDR+0x18

Bit Field name Reset RW Description

31:0 ADDRESS 0x00000000 RW Address for programming flash, auto-increment.

Table 126. FLASH – DATA0 register description: address offset FLASH_BASE_ADDR+0x40

Bit Field name Reset RW Description

31:0 DATA0 0xFFFFFFFF RW Program cycle data.

Table 127. FLASH – DATA1 register description: address offset FLASH_BASE_ADDR+0x44

Bit Field name Reset RW Description

31:0 DATA1 0xFFFFFFFF RW Program cycle data.

Table 128. FLASH – DATA2 register description: address offset FLASH_BASE_ADDR+0x48

Bit Field name Reset RW Description

31:0 DATA2 0xFFFFFFFF RW Program cycle data.

Table 129. FLASH – DATA3 register description: address offset FLASH_BASE_ADDR+0x4C

Bit Field name Reset RW Description

31:0 DATA3 0xFFFFFFFF RW Program cycle data.

Note: All RESERVED fields inside registers must always be written with their default value.

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3.12 GPIO

3.12.1 Introduction

The BlueNRG-2 offers 14 GPIOs (WCSP34 package), 15 GPIOs (QFN32 package) or 26 GPIOs (QFN48

package).

The programmable I/O pin can be configured for operating as:

•Programmable GPIOs

•Peripheral input or output line of standard communication interfaces

• PDM processor data/clock

• 2 PWM sources (PWM0 and PWM1 independently configurable) and 4 PWM output pins (IO2, IO3, IO4 and

IO5).

• 5 wakeup sources from standby and sleep mode

• Each I/O can generate an interrupt independently to the selected mode. Interrupts are generated depending

on a level or edge

3.12.2 Functional description

The table below shows the GPIO configuration table where each IO pin is associated with related functions.

Table 130. IO functional map

Pin name(1)

GPIO mode "000" Serial1 mode '001" Serial0 mode ‘100’ Serial2 mode '101'

Type Signal Type Signal Type Signal Type Signal

IO0 I/O GPIO 0 I UART_CTS I/O SPI_CLK O CPUCLK(2)

IO1 I/O GPIO 1 O UART_RTS I/O SPI_CS1 I PDM_DATA

IO2 I/O GPIO 2 O PWM0 O SPI_OUT O PDM_CLK

IO3 I/O GPIO 3 O PWM1 I SPI_IN - -

IO4 I/O GPIO 4 I UART_RXD I/O I2C2_CLK O PWM0

IO5 I/O GPIO 5 O UART_TXD I/O I2C2_DAT O PWM1

IO6 I/O GPIO 6 O UART_RTS I/O I2C2_CLK I PDM_DATA

IO7 I/O GPIO 7 I UART_CTS I/O I2C2_DAT O PDM_CLK

IO8 I/O GPIO 8 O UART_TXD I/O SPI_CLK I PDM_DATA

IO9 I/O GPIO 9 I SWCLK I SPI_IN O XO16/32M(3)

IO10 I/O GPIO 10 I SWDIO O SPI_OUT O CLK_32K

IO11 I/O GPIO 11 I UART_RXD I/O SPI_CS1 O CLK_32K

IO12 OD GPI 12 (4) - I/O I2C1_CLK - -

IO13 OD GPI 13(4) I UART_CTS I/O I2C1_DAT - -

IO14 I/O GPIO 14 I/O I2C1_CLK I/O SPI_CLK - -

IO15 I/O GPIO 15 I/O I2C1_DAT I/O SPI_CS1 - -

IO16 I/O GPIO 16 O PWM0 I SPI_IN - -

IO17 I/O GPIO 17 O PWM1 O SPI_OUT - -

IO18 I/O GPIO 18 O SPI_CS2 O UART_RTS - -

IO19 I/O GPIO 19 O SPI_CS3 I UART_CTS - -

IO20 I/O GPIO 20 I UART_CTS O SPI_CS2 - -

IO21 I/O GPIO 21 O PWM1 I/O SPI_CS1 - -

IO22 I/O GPIO 22 O PWM0 O SPI_CS3 - -

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Pin name(1)

GPIO mode "000" Serial1 mode '001" Serial0 mode ‘100’ Serial2 mode '101'

Type Signal Type Signal Type Signal Type Signal

IO23 I/O GPIO 23 O UART_TXD O SPI_OUT O PDM_CLK

IO24 I/O GPIO 24 I UART_RXD I SPI_IN I PDM_DATA

IO25 I/O GPIO 25 O UART_RTS I/O SPI_CLK O PDM_CLK

1. All the I2C pins require external pull-up

2. The bitfield SYSCLK_IO_EN of CLOCK_EN must be set in order to enable the CPUCLK signal.

3. The bitfield XO_IO_EN of CLOCK_EN must be set in order to enable the CPUCLK signal.

4. IO12 and IO13 can only be General Purpose Input pins (not output).

3.12.2.1 GPIO interrupts

Each IO in GPIO mode can be used as interrupt source from external signal. The trigger event is both edge and

level sensitive according to configuration. All the configuration are reported in table below.

Table 131. GPIO interrupt modes

Configuration

Interrupt mode

Falling edge Rising edge Both edges Low level High level

IOIS 00011

IOIBE 0 0 1 NA NA

IOIEV 0 1 NA 0 1

The interrupt is enabled by writing 1 in the MIS register, in the position with same number of the IO desired. Once

the interrupt occurs, it can be cleared by writing 1 in the IC register. All the interrupts drive a single interrupt signal

of the NVIC.

Each time the status of an IO matches its interrupt setting expressed by the registers IS, IBE and IEV, then the

correspondent bit in the RIS register is set. Before enabling the correspondent interrupt mask (register IE), it is

recommended to clear the RIS register by writing the correspondent bit of the register IC.

3.12.2.2 GPIO characteristics

By default all the GPIO pins are configured as input with related pull-up or pull-down enabled in order to have a

specified voltage level.

Table 132. Pin characteristics

Name Type Buffer strength(1) Pull-up / pull-

down availability

Default state after

reset

State during low

power modes

IO0 I/O High / very high

drive Pull-down GPIO input mode,

pull-down

High impedance

state

IO1 I/O Low / high drive Pull-down GPIO input mode,

pull-down

High impedance

state

IO2 I/O Low / high drive Pull-down GPIO input mode,

pull-down

High impedance

state

IO3 I/O Low / high drive Pull-down GPIO input mode,

pull-down

High impedance

state

IO4 I/O Low / high drive Pull-down GPIO input mode,

pull-down

High impedance

state

IO5 I/O Low / high drive Pull-down GPIO input mode,

pull-down

High impedance

state

IO6 I/O High / very high

drive Pull-down GPIO input mode,

pull-down

High impedance

state

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Name Type Buffer strength(1) Pull-up / pull-

down availability

Default state after

reset

State during low

power modes

IO7 I/O Low / high drive Pull-down GPIO input mode,

pull-down

High impedance

state

IO8 I/O Low /high drive Pull-down GPIO input mode,

pull-down

High impedance

state

IO9 I/O High / very High

drive Pull- up Serial1 mode

(SWCLK), pull-up

GPIO mode, with

configurable pull

IO10 I/O Low / high drive Pull- up Serial1 mode

(SWDIO), pull-up

GPIO mode, with

configurable pull

IO11 I/O Low / high drive Pull-up GPIO input mode,

pull-up

GPIO mode, with

configurable pull

IO12 I 10 mA(2) No pull GPIO input mode GPIO input mode

IO13 I 10 mA (2) No pull GPIO input mode GPIO input mode

IO14 I/O Low / high drive Pull-down GPIO input mode,

pull-down

High impedance

state

IO15 I/O Low /high drive Pull-down GPIO input mode,

pull-down

High impedance

state

IO16 I/O Low / high drive Pull-down GPIO input mode,

pull-down

High impedance

state

IO17 I/O Low / high drive Pull-down GPIO input mode,

pull-down

High impedance

state

IO18 I/O Low / high drive Pull-down GPIO input mode,

pull-down

High impedance

state

IO19 I/O Low /high drive Pull-down GPIO input mode,

pull-down

High impedance

state

IO20 I/O Low / high drive Pull-down GPIO input mode,

pull-down

High impedance

state

IO21 I/O Low / high drive Pull-down GPIO input mode,

pull-down

High impedance

state

IO22 I/O Low /high drive Pull-down GPIO input mode,

pull-down

High impedance

state

IO23 I/O Low /high drive Pull-down GPIO input mode,

pull-down

High impedance

state

IO24 I/O Low / high drive Pull-down GPIO input mode,

pull-down

High impedance

state

IO25 I/O Low / high drive Pull-down GPIO input mode,

pull-down

High impedance

state

1. See Table 213. Digital I/O specifications

2. Drive strength for I2C bus

Note: If the user needs pull-up or pull-down capability for driving the GPIO line, this must be done through an external

resistor.

All the IOs are in high impedance under reset. In low power modes (sleep and standby) the I/Os are configured as

follows:

-IO0 to IO8 and IO14 to IO25 are in high impedance state.

-IO9, IO10, IO11 can be configured as input or output, with or without internal pull by using the SLEEPIO_PE

-IO12 , IO13 are in input state no pull.

When the device is in low power mode, in order to avoid leakage, IO12 and IO13 need to be driven to logic level

high or low. If these pins are no used, it is recommended to pull them down through a pull-down resistor of 10 kΩ.

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The GPIO9, GPIO10 and GPIO11 can be configured to be used as output pin during the low power modes such

as standby and sleep. For more information see Section 3.4.1.5.3 GPIO special settings in low power modes.

3.12.3 GPIO registers

GPIO peripheral base address (GPIO_BASE_ADDR) 0x40000000.

Table 133. GPIO registers

Address

offset Name RW Reset Description

0x00 DATA RW 0x00000000

IO0 to IO25 data value.

Writing to a bit will drive the written value on the corresponding IO when

it is configured in GPIO mode and the output direction. Reading a bit

indicates the pin value

0x04 OEN RW 0x00000000

GPIO output enable register (1 bit per GPIO)

0: input mode

1: output mode

0x08 PE RW 0x03FFFFFF

Pull enable (1 bit per IO)

0: pull disabled

1: pull enabled

0x0C DS RW 0x00000000

IO driver strength (1 bit per IO).

0: low drive

1: high drive

0x10 IS RW 0x00000000

Interrupt sense register (1 bit per IO)

0: edge detection

1: level detection

0x14 IBE RW 0x00000000

Interrupt edge register (1 bit per IO).

0: single edge

1: both edges

0x18 IEV RW 0x00000000

Interrupt event register (1 bit per IO)

0: falling edge or low level

1: rising edge or high level

0x1C IE RW 0x00000000

Interrupt mask register (1 bit per IO)

0: Interrupt disabled

1: Interrupt enabled

0x20 RIS R 0x00000000 Raw interrupt status register (1 bit per IO)

0x24 MIS R 0x00000000 Masked interrupt status register (1 bit per IO)

0x28 IC W 0x00000000

Interrupt clear register (1 bit per IO)

0: no effect.

1: clear interrupt

0x2C MODE0 RW 0x00000000

Select mode for IO0 to IO7.

000b: GPIO mode

001b: Serial1 mode

100b: Serial0 mode

101b: Serial2 mode

Refer to the detailed description below.

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Address

offset Name RW Reset Description

0x30 MODE1 RW 0x00000110

Select mode for IO8 to IO15.

000b: GPIO mode.

001b: Serial1 mode.

100b: Serial0 mode.

101b: Serial2 mode.

Refer to the detailed description below.

0x34 MODE2 RW 0x00000000

Select mode for IO16 to IO23.

000b: GPIO mode.

001b: Serial1 mode.

100b: Serial0 mode.

101b: Serial2 mode.

Refer to the detailed description below.

0x38 MODE3 RW 0x00000000

Select mode for IO24 to IO25.

000b: GPIO mode.

001b: Serial1 mode.

100b: Serial0 mode.

101b: Serial2 mode.

Refer to the detailed description below.

0x3C DATS RW 0x00000000

Set some bits of DATA when in GPIO mode without affecting the others (1

bit per IO).

0: no effect.

1: set at 1 the bit

0x40 DATC RW 0x00000000

Clear some bits of DATA when in GPIO mode without affecting the others

(1 bit per IO)

0: no effect.

1: clear at 0 the bit

0x44 MFTX RW 0x00000000 Select the IO to be used as capture input for the MFTX timers. Refer to

the detailed description below.

Table 134. GPIO – DATA register description: address offset GPIO_BASE_ADDR+0x00

Bit Field

name Reset RW Description

31:0 DATA 0x00000000 RW

IO0 to IO25 data value.

Writing to a bit will drive the written value on the corresponding IO when it is configured

in GPIO mode and the output direction. Reading a bit indicates the pin value.

Table 135. GPIO – OEN register description: address offset GPIO_BASE_ADDR+0x04

Bit Field name Reset RW Description

31:0 OEN 0x00000000 RW

GPIO output enable register (1 bit per GPIO).

• 0: Input mode

•1: Output mode

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Table 136. GPIO – PE register description: address offset GPIO_BASE_ADDR+0x08

Bit Field name Reset RW Description

31:0 PE 0x03FFFFFF RW

Pull enable (1 bit per IO).

•0: Pull disabled.

• 1: Pull enabled.

Table 137. GPIO – DS register description: address offset GPIO_BASE_ADDR+0x0C

Bit Field name Reset RW Description

31:0 DS 0x00000000 RW

IO driver strength (1 bit per IO).

•0: low drive

•1: high drive

Table 138. GPIO – IS register description: address offset GPIO_BASE_ADDR+0x10

Bit Field name Reset RW Description

31:0 IS 0x00000000 RW

Interrupt sense register (1 bit per IO).

•0: Edge detection.

• 1: Level detection.

Table 139. GPIO – IBE register description: address offset GPIO_BASE_ADDR+0x14

Bit Field name Reset RW Description

31:0 IBE 0x00000000 RW

Interrupt edge register (1 bit per IO).

• 0: Single edge

•1: Both edges

Table 140. GPIO – IEV register description: address offset GPIO_BASE_ADDR+0x18

Bit Field name Reset RW Description

31:0 IEV 0x00000000 RW

Interrupt event register (1 bit per IO).

•0: Falling edge or low level.

•1: Rising edge or high level.

Table 141. GPIO – IE register description: address offset GPIO_BASE_ADDR+0x1C

Bit Field name Reset RW Description

31:0 IE 0x00000000 RW

Interrupt mask register (1 bit per IO).

The register MIS is the result of the AND logic between the register IE and the register

RIS.

•0: Interrupt mask disable

• 1: Interrupt mask enable

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Table 142. GPIO – RIS register description: address offset GPIO_BASE_ADDR+0x20

Bit Field

name Reset RW Description

31:0 RIS 0x00000000 R

Raw interrupt status register (1 bit per IO). Each time the status of an IO matches its

interrupt setting expressed by the registers IS, IBE and IEV, then the correspondent bit in

the RIS register is set. Before enabling the correspondent interrupt mask (register IE), it

is recommended to clear the RIS register by writing the correspondent bit of the register

Table 143. GPIO – MIS register description: address offset GPIO_BASE_ADDR+0x24

Bit Field name Reset RW Description

31:0 MIS 0x00000000 R Masked interrupt status register (1 bit per IO).

Table 144. GPIO – IC register description: address offset GPIO_BASE_ADDR+0x28

Bit Field

name Reset RW Description

31:0 IC 0x00000000 W

Interrupt clear register (1 bit per IO). This register clears the bit set in the RIS register.

If the same cleared bit is set in the IE register, the clear acts also in the MIS register as

consequence.

•0: No effect

• 1: Clear interrupt

Table 145. GPIO - MODE0 register description: address offset GPIO_BASE_ADDR+0x2C

Bit Field name Reset RW Description

2:0 IO0 0x0 RW IO0 mode

3 RESERVED 0x0 RW RESERVED

6:4 IO1 0x0 RW IO1 mode

7 RESERVED 0x0 RW RESERVED

10:8 IO2 0x0 RW IO2 mode

11 RESERVED 0x0 RW RESERVED

14:12 IO3 0x0 RW IO3 mode

15 RESERVED 0x0 RW RESERVED

18:16 IO4 0x0 RW IO4 mode

19 RESERVED 0x0 RW RESERVED

22:20 IO5 0x0 RW IO5 mode

23 RESERVED 0x0 RW RESERVED

26:24 IO6 0x0 RW IO6 mode

27 RESERVED 0x0 RW RESERVED

30:28 IO7 0x0 RW IO7 mode

31 RESERVED 0x0 RW RESERVED

Table 146. GPIO – MODE1 register description: address offset GPIO_BASE_ADDR+0x30

Bit Field name Reset RW Description

2:0 IO8 0x0 RW IO8 mode

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Bit Field name Reset RW Description

3 RESERVED 0x0 RW RESERVED

6:4 IO9 0x1 RW IO9 mode

7 RESERVED 0x0 RW RESERVED

10:8 IO10 0x1 RW IO10 mode

11 RESERVED 0x0 RW RESERVED

14:12 IO11 0x0 RW IO11 mode

15 RESERVED 0x0 RW RESERVED

18:16 IO12 0x0 RW IO12 mode

19 RESERVED 0x0 RW RESERVED

22:20 IO13 0x0 RW IO13 mode

23 RESERVED 0x0 RW RESERVED

26:24 IO14 0x0 RW IO14 mode

27 RESERVED 0x0 RW RESERVED

30:28 IO15 0x0 RW IO15 mode

31 RESERVED 0x0 RW RESERVED

Table 147. GPIO – MODE2 register description: address offset GPIO_BASE_ADDR+0x34

Bit Field name Reset RW Description

2:0 IO16 0x0 RW IO16 mode

3 RESERVED 0x0 RW RESERVED

6:4 IO17 0x0 RW IO17 mode

7 RESERVED 0x0 RW RESERVED

10:8 IO18 0x0 RW IO18 mode

11 RESERVED 0x0 RW RESERVED

14:12 IO19 0x0 RW IO19 mode

15 RESERVED 0x0 RW RESERVED

18:16 IO20 0x0 RW IO20 mode

19 RESERVED 0x0 RW RESERVED

22:20 IO21 0x0 RW IO21 mode

23 RESERVED 0x0 RW RESERVED

26:24 IO22 0x0 RW IO22 mode

27 RESERVED 0x0 RW RESERVED

30:28 IO23 0x0 RW IO23 mode

31 RESERVED 0x0 RW RESERVED

Table 148. GPIO – MODE3 register description: address offset GPIO_BASE_ADDR+0x38

Bit Field name Reset RW Description

2:0 IO24 0x0 RW IO24 mode

3 RESERVED 0x0 RW RESERVED

6:4 IO25 0x0 RW IO25 mode

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Bit Field name Reset RW Description

31:7 RESERVED 0x0 RW RESERVED

Table 149. GPIO – DATS register description: address offset GPIO_BASE_ADDR+0x3C

Bit Field name Reset RW Description

31:0 DATS 0x00000000 RW

Set some bits of DATA when in GPIO mode without affecting the others (1 bit per IO).

•0: No effect

• 1: Set at 1 the bit

Table 150. GPIO – DATC register description: address offset GPIO_BASE_ADDR+0x40

Bit Field name Reset RW Description

31:0 DATC 0x00000000 RW

Clear some bits of DATA when in GPIO mode without affecting the others (1 bit per

IO).

• 0: No effect

• 1: Clear at 0 the bit

Table 151. GPIO - MFTX register description: address offset GPIO_BASE_ADDR+0x44

Bit Field name Reset RW Description

7:0 MFT1_TIMER_A 0x0 RW

Selects which IO must be used as input pin TnA for the MFT1

peripheral. Mode 2 and mode 4 only.

• 0x00: IO0

• 0x01: IO1

• 0x02: IO2

• ...

• 0x19: IO25

15:8 MFT1_TIMER_B 0x0 RW

Selects which IO must be used as input pin TnB for the MFT1

peripheral. Mode 2 and mode 4 only.

•0x00: IO0

• 0x01: IO1

• 0x02: IO2

• ...

• 0x19: IO25

23:16 MFT2_TIMER_A 0x0 RW

Selects which IO must be used as input pin TnA for the MFT2

peripheral. Mode 2 and mode 4 only.

•0x00: IO0

• 0x01: IO1

• 0x02: IO2

• ...

• 0x19: IO25

31:24 MFT2_TIMER_B 0x0 RW

Selects which IO must be used as input pin TnB for the MFT2

peripheral. Mode 2 and mode 4 only.

•0x00: IO0

• 0x01: IO1

• 0x02: IO2

• ...

• 0x19: IO25

Note: All RESERVED fields inside registers must always be written with their default value.

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3.13 MFT

3.13.1 MFT introduction

The BlueNRG-1 integrates two multi functions timers (MFT).

Main features are:

•Two 16-bit programmable timer/counters.

• Two 16-bit reload/capture registers that function either as reload registers or as capture registers, depending

on the mode of operation.

• An 8-bit fully programmable clock prescaler.

• Clock source selectors that allow each counter to operate in:

– Pulse-accumulate mode

– External-event mode

– System clock with configurable prescaler

• Two I/O pins (TnA and TnB) with programmable edge detection that operate as:

– Capture and preset inputs

– External event (clock) inputs

– PWM outputs

• Two interrupts, one for each counter, that can be triggered by a:

– Timer underflow

– Timer reload

– Input capture

– Pulse train for generation of single or multiple PWM pulses.

3.13.2 MFT functional description

The MFT can be configured in five different modes. At each mode is associated a particular function for the two

timers both for counter and reload registers as reported in Table 152. MFT modes.

Table 152. MFT modes

Mode Description Timer Counter 1

(TnCNT1)

Reload / capture A

(TnCRA)

Reload / Capture B

(TnCRB)

Timer Counter 2

(TnCNT2)

1PWM and system timer or

external event counter Counter for PWM Auto reload A = PWM time

1Auto reload B = PWM time 2 System time or

external event

1a PWM pulse train Counter for PWM Auto reload A = PWM time

1Auto reload B= PWM time 2 Pulse counter

2Dual-input capture and

system timer

Capture A and B time

base

Capture Timer/Counter 1

value upon TnA event

Capture Timer/Counter 1

value upon TnB event System timer

3 Dual independent timer Time base for first

timer

Reload register for Timer/

Counter 1

Reload register for Timer/

Counter 2

Time base for

second timer

4Single-input capture and

single timer

Time base for first

timer

Reload register for Timer/

Counter 1

Capture Timer/Counter 1

value upon TnB event Capture B time base

3.13.2.1 MFT mode 1: processor-independent PWM

In mode 1, the Timer/Counter 1 (register TnCNT1) can be used to generate a PWM signal on an output pin of

the device. In this mode, the PWM output can emulate a clock signal with customized duty-cycle. Indeed, the

TnCNT1 register is alternatively reloaded with the values in TnCRA and TnCRB registers. The initial value of the

PWM output signal can be selected by software to be either high or low thanks to the TnAOUT bit in TnMCTRL

Figure 16. PWM signal on TnA pin below.

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Figure 15. PWM signal on TnA pin

TnMCTRL TnAOUT bit = 0

TnCRA TnCRA

TnCRB TnCRB

TnCNT1

TnMCTRL TnAOUT bit = 1

TnCRA TnCRA

TnCRB TnCRB

TnCNT1

When started, the first time the Timer/Counter 1 starts with preprogrammed value in the register TnCNT1 and

count down at the clock rate selected by the Timer/Counter 1 clock selector (TnCKC register). When an underflow

occurs, the TnCNT1 register is reloaded alternatively with TnCRA and TnCRB registers (in this order) and

counting proceeds downward from the loaded value.

Any time the counter is stopped by choosing "no-clock" in the TnCKC register, it obtains its first reload value after

it has been started again from the TnCRA register. Each time the counter is stopped and then restarted, it obtains

its first reload value from the TnCRA register. This is true whether the timer is restarted upon reset, after entering

mode 1 from another mode, or after stopping and restarting the clock with the TnCKC register.

The mode 1 is selected in the TnMDSEL field of TnMCTRL register

In figure below the block diagram related to the MFT mode 1.

Figure 16. MFT mode 1 block diagram

Timer/Counter 1

TnCNT1

Reload A = TnCRA

Reload B = TnCRB

Timer/Counter 2

TnCNT2

TnAPND

TnBPND

Timer

Interrupt A

Timer

Interrupt A

TnA

Timer

Interrupt B

TnAIEN

TnAEN

TnBIEN

TnDIEN

TnDPND

TnB

Timer 1

clock

Timer 2

clock

Clock

selector

underflow

In this mode, the timer toggles the TnA output upon underflow, which is connected to PWMx pin of the device.

This generates a clock signal on TnA with the width and duty cycle controlled by the values stored in the TnCRA

and TnCRB registers.

This is a "processor-independent" PWM clock because once the timer is set up, no more interaction is required

from the software and the CPU in order to generate a continuous PWM signal. Refer to Section 3.13.2.6 Timer

IO functions for additional details.

The timer can generate separate interrupts upon reload from TnCRA and TnCRB. The TnAPND or TnBPND

flags, which are set by the hardware upon occurrence of a timer reload, indicate which interrupt has occurred.

Refer to Section 3.13.2.8 Timer interrupts for detailed information.

In this mode, the Timer/Counter 2 can be used as a simple system timer or as an external-event counter.

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The Timer/Counter 2 counts down with the clock selected by Timer/Counter 2 clock selector (TnCKC register),

and can be configured to generate an interrupt upon underflow if enabled by the TnDIEN bit.

The interrupts can be enabled or disabled by software.

3.13.2.2 MFT mode 1a: PWM pulse-train mode

The mode 1a is used to output a PWM signal thanks to the Timer/Counter 1 as for mode 1, but only in a time

window defined by the Timer/Counter 2 (TnCNT2). Indeed, the Timer/Counter 2 is used to specify the number of

pulses to output on the TnA pin.

The mode 1a corresponds to the mode 1 selected in the TnMDSEL field of TnMCTRL register with in addition the

TnPTEN bit set always in the TnMCTRL register. In mode 1a, the Timer/Counter 1 (TnCNT1 register) alternatively

is reloaded by TnCRA and TnCRB registers after starting from the value in the TnCNT1 register as for the mode 1

and toggles the TnA output connected to PWMx GPIO each time an underflow occurs. In parallel, a trigger pulse

is sent to the Timer/Counter 2 (TnCNT2 register), decrementing it by one. If the TnCNT2 register has reached

the underflow condition and the end-of-pulse condition is detected by the trigger logic as well, the clock of the

Timer/Counter 1 is disabled immediately.

The figure below shows the block diagram related to the MFT mode 1a.

Figure 17. MFT mode 1a block diagram

Timer/Counter 1

TnCNT1

Reload A = TnCRA

Reload B = TnCRB

Timer/Counter 2

TnCNT2

TnAPND

TnBPND

Timer

Interrupt A

Timer

Interrupt A

TnA

Timer

Interrupt B

TnAIEN

TnAEN

TnBIEN

TnDIEN

TnDPND

TnB

Timer 1

clock

TnPTET

Trigger Logic

underflow

TnPTSE

In mode 1a, Timer/Counter 2 behaves differently from the way it behaves in the other modes. If an underflow

condition occurs, the counter is preset to 0x0000 and not 0xFFFF.

The TnCNT1 register starts to count:

•either on an external event on TnB input,

• or by software if the enable TnPTSE bit has been set by setting the TnPTET bit.

Note: The start of count request through TnPTET bit setting when software trigger option is chosen must be done after

the MFT is enabled (TnEN bit in TnMCTRL register).

Any time the counter is stopped by choosing "no-clock" by the Timer/Counter 1 clock selector (TnCKC register),

it obtains its first reload value after it has been started again from the TnCRA register. Upon reset, the MFT is

disabled. Every time this mode starts, the first reload is from register TnCRA. Once the underflow condition for

TnCNT2 has been reached, TnCNT2 must be initialized again by the application. It is not reloaded by any reload

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Timer/Counter 2 can be configured to generate an interrupt upon underflow if enabled by the TnDIEN bit. Refer to

Section 3.13.2.6 Timer IO functions for additional details.

In pulse-train mode, the value of TnCNT2 register specifies the number of pulses to be generated, plus one

additional pulse (TnCNT2+1 number of pulses).

In pulse-train mode, the trigger logic uses events on TnB to enable the Timer/Counter 1 clock. This function has to

be enabled by setting the TnPTSE bit to 0.

The TnB pin can be configured to sense either rising or falling edges.

The Timer/Counter 1 can be configured to toggle the TnA output bit upon underflow. This results in the generation

of a pulse signal on TnA, with the width and duty cycle controlled by the values stored in the TnCRA and TnCRB

registers. This is a processor-independent PWM signal because once the timer is set up, no more interactions

are required from the software or the CPU in order to generate other PWM pulses. The initial value of the PWM

output signal can be selected by software to be either high or low. Refer to Section 3.13.2.6 Timer IO functions

for additional details.

The timer can be configured to generate separate interrupts upon reload from TnCRA and TnCRB. The TnAPND

or TnBPND flags, which are set by the hardware upon occurrence of a timer reload, indicate which interrupt has

occurred. The interrupts can be enabled or disabled under software control. Refer to Section 3.13.2.8 Timer

interrupts for detailed information.

3.13.2.3 MFT mode 2: dual-input capture mode

The mode 2 is used to capture transitions on two selected input pads of the device. The Timer/Counter1 can be

used to manage the dual-capture feature as follows:

•A transition on input pad connected to the TnA pin of the MFT generates a transfer of TnCNT1 register value

in TnCRA register.

• A transition on input pad connected to the TnB pin of the MFT generates a transfer of TnCNT1 register value

in TnCRB register.

The Timer/Counter2 can be used:

• As a system counter: to count down at the rate of the selected clock.

Note: The device input pad selection is done using the register MFTX of the GPIO peripheral.

The transition edge to capture has to be defined in TnAEDG and TnBEDG bits of the TnMCTRL register.

The TnA and TnB inputs can be configured to perform a counter preset to 0xFFFF upon reception of a valid

capture event using TnAEN and TnBEN bits in TnMCTRL register. In this case, the current value of the counter

is transferred to the corresponding capture register and then the counter is preset to 0xFFFF. Using this approach

directly allows the software to determine the on-time, off-time, or period of an external signal, while reducing CPU

overhead.

In Figure 19. MFT mode 2 block diagram below the block diagram related to the MFT mode 2.

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Figure 18. MFT mode 2 block diagram

Timer/Counter 1

TnCNT1

Capture A TnCRA

Capture B TnCRB

Timer/Counter 2

TnCNT2

TnAPND

Timer

Interrupt B

TnDIEN

TnDPND

TnA

Timer 1

clock

Timer 2

clock

preset

Timer

Interrupt A

TnAIEN

TnBPND

TnB

Timer

Interrupt A

TnBIEN

TnCPND

Timer

Interrupt A

TnCIEN

underflow

TnAEN

TnBEN

underflow

The input signal on TnA and TnB must have a pulse width equal to or greater than one system clock cycle. The

value captured in the TnCRA register at different times reflects the elapsed time between transitions on the TnA

pin. The same is true for the TnCRB register and TnB pin. Each input pin can be configured to sense either

positive edge or negative edge transitions.

The timer can be configured to generate interrupts on reception of a transition on either TnA or TnB, which can

be enabled or disabled separately by the TnAIEN and TnBIEN bits. An underflow of TnCNT1 can generate an

interrupt if enabled by the TnCIEN bit. All three interrupts have individual pending flags associated with them. See

Section 3.13.2.8 Timer interrupts for further details.

The Timer/Counter 2 can be used as a simple system timer in this mode of operation. The TnCNT2 register

counts down with the clock selected by the Timer/Counter 2 clock selector (TnCKC register), and can be

configured to generate an interrupt upon underflow if enabled by the TnDIEN bit. See Section 3.13.2.8 Timer

interrupts for detailed information.

The Timer/Counter 1 cannot operate in the pulse-accumulate or external-event counter modes, since the TnB pin

is used as a capture input. Selecting either of these modes for the Timer/Counter 1 causes the TnCNT1 register

to be stopped. However, all available clock source modes may be selected for the Timer/Counter 2. Thus, it is

possible to determine the number of capture events on TnB or the elapsed time between capture events on TnB

by using the Timer/Counter 2.

3.13.2.4 MFT mode 3: dual independent timer/counter mode

This mode 3 allows using the Timer/ Counter 1 and Timer/ Counter 2 separately.

The Timer/ Counter1 can be used:

•As a system counter: to count down at the rate of the selected clock.

• To generate a 50% duty-cycle clock signal on TnA pin connected to the PWMx pin of the device (the

TnCNT1 register is reloaded with the value of the TnCRA register on underflow event).

• To be an event counter using TnB pin as an external event or pulse-accumulate input.

The Timer/Counter 2 can be used:

• As a system counter: to count down at the rate of the selected clock.

• To be an event counter using TnB pin as an external event or pulse-accumulate input.

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In figure below the block diagram related to the MFT mode 3.

Figure 19. MFT mode 3 block diagram

Timer/Counter 1

TnCNT1

Reload A TnCRA

Reload B TnCRB

Timer/Counter 2

TnCNT2

TnAPND

Timer

Interrupt A

TnA

Timer

Interrupt B

TnAIEN

TnAEN

TnDIEN

TnDPND

TnB

Timer 1

clock

Timer 2

clock

Clock

selector

underflow

In mode 3, the Timer/Counter is configured to operate as a dual independent system timer or dual external-event

counter. In addition, the Timer/Counter 1 can generate a 50% duty cycle PWM signal on the TnA pin. The TnB

pin can be used as an external-event input or pulse-accumulate input, and serve as the clock source to either

Timer/Counter 1 or Timer/Counter 2. Both counters can also be operated from the prescaled system clock.

The Timer/Counter 1 counts down at the rate of the selected clock. Upon underflow, TnCNT1 register is

reloaded from the TnCRA register and counting proceeds. If enabled, the TnA pin toggles upon underflow of

the TnCNT1 register. The initial value of the TnA output can be selected by software to be either high or low. See

Section 3.13.2.6 Timer IO functions for additional details.

In addition, the TnAPND interrupt-pending flag is set, and a timer interrupt A is generated if the TnAIEN bit is set.

See Section 3.13.2.8 Timer interrupts for detailed information.

Since TnA toggles upon every underflow, a 50% duty-cycle PWM signal can be generated on TnA without

requiring any interaction of the software or the CPU.

The Timer/Counter 2 counts down at the rate of the selected clock. Upon every underflow of the TnCNT2 register,

the value contained in the TnCRB register is loaded into TnCNT2 and counting proceeds downward from that

value.

In addition, the TnDPND interrupt-pending flag is set and a timer interrupt B is generated if the TnDIEN bit is set.

See Section 3.13.2.8 Timer interrupts for detailed information.

3.13.2.5 MFT mode 4: input-capture plus timer mode

This mode 4 is combination of mode 3 and mode 2.

The Timer/Counter1 can be used:

•As a system counter: to count down at the rate of the selected clock.

• To generate a 50% duty-cycle clock signal on TnA pin connected to the PWMx pin of the device (the

TnCNT1 register is reloaded with the value of the TnCRA register on underflow event).

The Timer/Counter 2 can be used:

• As a system counter: to count down at the rate of the selected clock.

• A transition on input pad connected to TnB pin of the MFT generates a transfer of TnCNT2 register value in

TnCRB register.

Note: The device input pad selection is done using the register MFTX of the GPIO peripheral.

The transition edge to capture has to be defined in TnBEDG bit of the TnMCTRL register. The TnB input can

be configured to perform a counter preset to 0xFFFF upon reception of a valid capture event using TnBEN bit in

TnMCTRL register.

In figure below the block diagram related to the MFT mode 4.

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Figure 20. MFT mode 4 block diagram

Timer/Counter 1

TnCNT1

Reload A TnCRA

TnAPND

Timer

Interrupt A

TnA

TnAIEN

TnAEN

Timer 1

clock

underflow

Timer/Counter 2

TnCNT2

Capture B TnCRB

TnBPND

TnB

Timer 2

clock

preset

Timer

Interrupt A

TnBIEN

TnDPND

Timer

Interrupt B

TnDIEN

TnBEN

This mode is a combination of mode 3 and mode 2, and makes it possible to operate Timer/Counter 2 as a single

input-capture timer while the Timer/Counter 1 can be used as a system timer as described above.

The Timer/Counter 1 starts counting down once a clock has been enabled. Upon underflow, the TnCNT1 register

is reloaded from the TnCRA register, and counting proceeds downward from that value. If enabled, the TnA pin

toggles upon every underflow of the TnCNT1 register. The initial value of the TnA output signal can be selected

by software to be either high or low. See Section 3.13.2.6 Timer IO functions for additional details.

In addition, the TnAPND interrupt-pending flag is set and a timer interrupt A is generated if the TnAIEN bit is set.

See Section 3.13.2.6 Timer IO functions for additional details.

Since TnA toggles upon every underflow, a 50% duty-cycle PWM signal can be generated on TnA without

requiring any interaction with the software or the CPU.

The Timer/Counter 2 starts counting down once a clock has been enabled. When a transition is received on

TnB, the value contained in the TnCNT2 register is transferred to TnCRB register, and the interrupt-pending flag

TnBPND is set. A timer interrupt A is generated if enabled. The software can enable a preset of the counter to

0xFFFF upon detection of a transition on TnB. In this case, the current value of the TnCNT2 register is transferred

to TnCRB register, followed by a preset of the counter to 0xFFFF. TnCNT2 starts counting downwards from

0xFFFF until the next transition is received on TnB, which causes the procedure of capture and preset to be

repeated. The underflow of the TnCNT2 register causes the TnDPND interrupt-pending flag to be set, and can

also generate a timer interrupt B if enabled. See Section 3.13.2.8 Timer interrupts for detailed information.

The input signal on TnB must have a pulse width equal to or greater than one system clock cycle. TnB can be

configured to sense either rising or falling edges. The Timer/Counter 2 cannot operate in the pulse-accumulate or

external-event counter modes since the TnB input is used as a capture input. Selecting either of these modes for

the Timer/Counter 2 causes the TnCNT2 register to be stopped.

However, all available clock source modes may be selected for the Timer/Counter 1. Thus using the TnCNT1

events on TnB.

3.13.2.6 Timer IO functions

There are two pins associated with each instance of the MFTX. The pins are called TnA and TnB. The

functionality of TnA and TnB depends on the mode of operation and the value of the TnAEN and TnBEN bits.

Table 153. MFT IO functions shows the function of TnA and TnB for various modes of operation. Note that if TnA

functions as a PWM output, TnAOUT defines the initial and present value of TnA. For example, if the user wishes

to start with TnA high, TnAOUT needs to be set before enabling the timer clock.

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Table 153. MFT IO functions

Pin TnAEN

TnBEN

Mode 1 Mode 1a Mode 2 Mode 3 Mode 4

PWM and counter PWM pulse train Dual-input capture

and counter

Dual independent

counter

Input capture plus

timer

TnA

TnAEN = 0

TnBEN = X No output No output Capture TnCNT1 into

TnCRA No output toggle No output toggle

TnAEN = 1

TnBEN = X

Toggle output on

underflow of TnCNT1

Toggle output on

underflow of TnCNT1

Capture TnCNT1 into

TnCRA and preset

TnCNT1

Toggle output on

underflow of TnCNT1

Toggle output on

underflow of TnCNT1

TnB

TnAEN = X

TnBEN = 0

External event or pulse

accumulate input

External event if

TnPTSE = 0

Capture TnCNT1 into

TnCRB

External event or pulse

accumulate input

Capture TnCNT2 into

TnCRB

TnAEN = X

TnBEN = 1

External event or pulse

accumulate input

External event if

TnPTSE = 0

Capture TnCNT1 into

TnCRA and preset

TnCNT1

External event or pulse

accumulate input

Capture TnCNT2 into

TnCRB and preset

TnCNT2

3.13.2.7 IO configuration linked to MFT timers

The MFT timers can be connected to the GPIOs for the following features:

•Input signal used to trigger the timer in capture mode.

•Output signal when a PWM mode is used

In capture mode, the timer waits for an external IO event to start counting. The chosen IO for capture is

programmed through the register MFTX of the GPIO peripheral. This register allows configuring input capture IO

for Timer/Counter 1 and Timer/Counter 2 of both MFT1 and MFT2, depending on which timer(s) are configured in

capture mode.

In PWM mode, the signal is output on PWM0 IO for MFT1 and PWM1 for MFT2. Those IOs are available at

different GPIOs thanks to alternate option. So to output the chosen PWM signal, it is necessary to configure the

IO with the dedicated mode.

3.13.2.8 Timer interrupts

The MFT has four interrupt sources, which are mapped to two different system interrupts. All sources have a

pending flag associated with them, and can be enabled or disabled by software. The pending flags are named

TnXPND, where n denotes the instance of the module, and X represents a letter from A to D. An interrupt enable

flag (TnXIEN) is associated with each interrupt-pending flag. Interrupt sources A, B and C can each generate a

timer interrupt MFT1A for MFT1 and MFT2A for MFT2, whereas interrupt source D can generate a timer interrupt

MFT1B for MFT1 and MFT2B for MFT2. Not all interrupt sources are available in all modes. Table 154. MFT

interrupt functions shows which events can trigger an interrupt in which mode of operation.

Table 154. MFT interrupt functions

MFT interrupt Interrupt

pending flag

Mode 1 Mode 1a Mode 2 Mode 3 Mode 4

PWM and

counter PWM pulse train Dual-input capture

and counter

Dual independent

counter

Input capture

plus timer

Timer interrupt A

(MFT1A, MFT2A)

TnAPND TnCNT1 reload

from TnCRA

TnCNT1 reload

from TnCRA

Input capture on

TnA transition

TnCNT1 reload from

TnCRA

TnCNT1 reload

from TnCRA

TnBPND TnCNT1 reload

from TnCRB

TnCNT1 reload

from TnCRB

Input capture on

TnB transition N/A Input capture on

TnB transition

TnCPND N/A N/A TnCNT1

underflow N/A N/A

Timer interrupt B

(MFT1B, MFT2B) TnDPND TnCNT2

underflow

TnCNT2

underflow

TnCNT2

underflow

TnCNT2 reload from

TnCRB

TnCNT2

underflow

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3.13.3 MFT registers

MFT1 peripheral base address (MFT1_BASE_ADDR) 0x40D00000.

MFT2 peripheral base address (MFT2_BASE_ADDR) 0x40E00000.

Table 155. MFTX registers

Address offset Name RW Reset Description

0x00 TnCNT1 RW 0x00000000 Timer / Counter1 register. Refer to the detailed description below.

0x04 TnCRA RW 0x00000000 Capture / Reload A register. Refer to the detailed description below.

0x08 TnCRB RW 0x00000000 Capture / Reload B register. Refer to the detailed description below.

0x0C TnCNT2 RW 0x00000000 Timer / Counter 2 register. Refer to the detailed description below.

0x10 TnPRSC RW 0x00000000 Clock prescaler register. Refer to the detailed description below.

0x14 TnCKC RW 0x00000000 Clock unit control register. Refer to the detailed description below.

0x18 TnMCTRL RW 0x00000000 Timer mode control register. Refer to the detailed description below.

0x1C TnICTRL RW 0x00000000 Timer interrupt control register. Refer to the detailed description

below.

0x20 TnICLR RW 0x00000000 Timer interrupt clear register. Refer to the detailed description below.

Table 156. MFTX – TnCNT1 register description: address offset MFTX_BASE_ADDR+0x00

Bit Field name Reset RW Description

15:0 TnCNT1 0x0000 RW

The Timer/Counter 1 register is a 16-bit RW register that is not altered by reset and thus

contains random data upon power-up. Reading the register returns the current value of

the Timer/Counter 1. TnCNT1 can only be written by the software when MFT is enabled

(TnEN = 1). When MFT is disabled (TnEN = 0), write operations on TnCNT1 register are

ignored.

31:16 RESERVED 0x0 RW RESERVED

Table 157. MFTX – TnCRA register description: address offset MFTX_BASE_ADDR+0x04

Bit Field name Reset RW Description

15:0 TnCRA 0x0000 RW

The Capture/Reload A register is a 16-bit RW register that is not affected by reset and

thus contains random data upon power-up. The software may read the register at any

time. However, the register can only be written by the software when MFT is enabled

(TnEN = 1). When MFT is disabled (TnEN = 0), write operations on TnCRA register are

ignored.

31:16 RESERVED 0x0 RW RESERVED

Table 158. MFTX – TnCRB register description: address offset MFTX_BASE_ADDR+0x08

Bit Field name Reset RW Description

15:0 TnCRB 0x0000 RW

The Capture/Reload B register is a 16-bit RW register that is not affected by reset and

thus contains random data upon power-up. The software may read the register at any

time. However, the register can only be written by the software when MFT is enabled

(TnEN = 1). When MFT is disabled (TnEN = 0), write operations on TnCRB register are

ignored.

31:16 RESERVED 0x0 RW RESERVED

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Table 159. MFTX – TnCNT2 register description: address offset MFTX_BASE_ADDR+0x0C

Bit Field name Reset RW Description

15:0 TnCNT2 0x0000 RW

The Timer/Counter 2 register is a 16-bit RW register that is not altered by reset and thus

contains random data upon power-up. Reading the register returns the current value of

the Timer/Counter 2. TnCNT2 can only be written by the software when MFT is enabled

(TnEN = 1). When MFT is disabled (TnEN = 0), write operations on TnCNT2 register are

ignored.

31:16 RESERVED 0x0 RW RESERVED

Table 160. MFTX – TnPRSC register description: address offset MFTX_BASE_ADDR+0x10

Bit Field name Reset RW Description

7:0 TnPRSC 0x00 RW

The clock prescaler register is an 8-bit RW register. It contains the current value of the

clock prescaler, which determines the timer clock prescaler ratio. The register value can be

changed at any time. In all operating modes except pulse-train (mode1a), a modified value

is used upon an underflow of the internal prescaler counter. In mode 1a, the new value is

used either upon start of a new pulse train (a write to TnPTSE), or upon an event on TnB

(if TnPTET=1). The timer clock is generated by dividing the system clock by TnPRSC + 1.

Therefore, the maximum timer clock frequency is equal to the frequency of the system clock

(TnPRSC = 0x00), and the minimum timer clock is the frequency of the system clock divided

by 256 (TnPRSC = 0xFF).

31:8 RESERVED 0x0 RW RESERVED

Table 161. MFTX - TnCKC register description: address offset MFTX_BASE_ADDR+0x14

Bit Field name Reset RW Description

2:0 TnC1CSEL 0x0 RW

Determines the clock mode for the Timer/Counter 1:

•000b: No clock (Timer/Counter 1 stopped).

• 001b: System clock with configurable prescaler (register TnPRSC).

• 010b: External event on TnB (mode 1 and 3 only).

• 011b: Pulse accumulate (mode 1 and 3 only).

5:3 TnC2CSEL 0x0 RW

Determines the clock mode for the Timer/Counter 2:

• 000b: No clock (Timer/Counter 2 stopped).

• 001b: System clock with configurable prescaler (register TnPRSC).

• 010b: External event on TnB (mode 1 and 3 only).

• 011b: Pulse accumulate (mode 1 and 3 only).

31:6 RESERVED 0x0 RW RESERVED

Table 162. MFTX - TnMCTRL register description: address offset MFTX_BASE_ADDR+0x18

Bit Field name Reset RW Description

1:0 TnMDSEL 0x0 RW

MFT mode select:

• 00b: Mode 1 or 1a: PWM mode and system timer or pulse train mode

•01b: Mode 2: Dual-input capture mode and system timer

• 10b: Mode 3: Dual independent mode Timer/Counter mode

• 11b: Mode 4: Single timer and single input capture mode

2 TnAEDG 0x0 RW

Configure the TnA edge polarity for trigging an action:

0: Input is sensitive to falling edges.

1: Input is sensitive to rising edges.

3 TnBEDG 0x0 RW Configure the TnB edge polarity for trigging an action:

0: Input is sensitive to falling edges.

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Bit Field name Reset RW Description

1: Input is sensitive to rising edges.

4 TnAEN 0x0 RW

Enables TnA to either function as a preset input or as a PWM output depending on the

mode of operation. If the bit is set (1) while operating in the dual-input capture mode (mode

2), a transition on TnA causes TnCNT1 to be preset to 0xFFFF. In the remaining modes of

operation, setting TnAEN enables TnA to function as a PWM output

0: TnA input disable.

1: TnA input enable.

5TnBEN 0x0 RW

TnB Enable: If set (1) and while operating in dual-input capture mode (mode 2) or input

capture and timer mode (mode 4), a transition on TnB causes the corresponding Timer/

Counter to be preset to 0xFFFF. In mode 2, TnCNT1 is preset to 0xFFFF, while in mode 4,

TnCNT2 is preset to 0xFFFF. The bit has no effect while operating in any other modes than

mode 2 or mode 4.

0: TnB input disable.

1: TnB input enable.

6 TnAOUT 0x0 RW

The TnA output data contains the value of the TnA when used as PWM output. The bit

will be set and cleared by the hardware and thus reflects the status of TnA. The bit can be

read or written by software at any time. If the hardware is attempting to toggle the bit at the

same time that software writes to the bit, the software write will take precedence over the

hardware update. The bit has no effect when TnA is used as an input or when the module

is disabled:

0: TnA pin is low.

1: TnA pin is high.

7 TnEN 0x0 RW

MFT Enable: This bit enables or disables the MFT peripherals. When the bit is set (1), MFT

is enabled, and when the bit is cleared (0), MFT is disabled. When MFT is disabled, all

clocks to the counter unit are stopped, thus decreasing power consumption to a minimum.

For that reason, the Timer/Counter registers (TnCNT1, TnCNT2), the Capture/Reload

registers (TnCRA, TnCRB) and the interrupt-pending bits (TnXPND) cannot be written by

software. Furthermore, the 8-bit clock prescaler and the interrupt-pending bits are reset and

the TnA I/O pin becomes an input:

0: MFT disable

1: MFT enable

8TnPTEN 0x0 RW

This bitfield enable the mode 1a. If set (1) while TnMDSEL is set to 00b, the Timer/Counter

1 operates in PWM pulse-train mode (mode 1a). The bit has no effect while TnMDSEL is

set to any value other than 00b.

0: Mode 1a not selected.

1: Mode 1a selected (if TnMDSEL = 00b).

9TnPTSE 0x0 RW

Tn Pulse-Train software trigger enable: if set (1) while operating in PWM pulse-train mode

(mode 1a), the pulse-train generation can only be triggered by setting the TnPTET to 1. If

the TnPTSE bit is reset (0), pulses are generated only if a transition occurs on TnB. The bit

has no effect while operating in any other modes than timer mode 1a:

0: No effect

1: Pulse-train generation trigger (in mode 1a)

10 TnPTET 0x0 RW

Tn Pulse-Train event trigger: if set (1) while operating in pulse-train mode (mode 1a)

and the TnPTSE bit is set (1), pulse-train generation is triggered. When Timer/Counter 2

(TnCNT2) reaches its underflow condition, this bit is reset (0). If the TnPTSE bit is not

set (0) while operating in pulse-train mode (mode 1a), the TnPTET bit cannot be written.

Therefore, a 1 in TnPTET indicates that an external event started a pulse-train generation

that is not yet finished. When the pulse-train is finished, the bit is reset to 0:

0: No pulse-train event trigger occurred.

1: Pulse-train event trigger occurred (in mode 1a).

31:11 RESERVED 0x0 RW RESERVED

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Table 163. MFTX - TNICTRL register description: address offset MFTX_BASE_ADDR+0x1C

Bit Field name Reset RW Description

0 TNAPND 0x0 R

Timer interrupt A pending:·

0: No interrupt source pending.

1: Interrupt source pending.

1 TNBPND 0x0 R

Timer interrupt B pending:

0: No interrupt source pending.

1: Interrupt source pending.

2 TNCPND 0x0 R

Timer interrupt C pending:

0: No interrupt source pending.

1: Interrupt source pending.

3 TNDPND 0x0 R

Timer interrupt D pending:

0: No interrupt source pending.

1: Interrupt source pending.

4 TNAIEN 0x0 RW

Timer interrupt A enable:

0: Interrupt disabled.

1: Interrupt enabled.

5 TNBIEN 0x0 RW

Timer interrupt B enable:

0: Interrupt disabled.

1: Interrupt enabled.

6 TNCIEN 0x0 RW

Timer interrupt C enable:

0: Interrupt disabled.

1: Interrupt enabled

7 TNDIEN 0x0 RW

Timer interrupt D enable:

0: Interrupt disabled.

1: Interrupt enabled.

31:8 RESERVED 0x0 RW RESERVED

Table 164. MFTX - TNICLR register description: address offset MFTX_BASE_ADDR+0x20

Bit Field name Reset RW Description

0 TNACLR 0x0 W 1: clear the timer pending flag A

1 TNBCLR 0x0 W 1: clear the timer pending flag B.

2 TNCCLR 0x0 W 1: clear the timer pending flag C.

3 TNDCLR 0x0 W 1: clear the timer pending flag D.

31:4 RESERVED 0x0 W RESERVED

Note: All RESERVED fields inside registers must always be written with their default value.

3.14 Watchdog

3.14.1 Introduction

The watchdog timer provides a way of recovering from software crashes.

The watchdog monitors the interrupt and asserts a reset signal if the interrupt remains unserved for the entire

programmed period.

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The watchdog clock is used to generate a regular interrupt, depending on a programmed value. It is counting

down at a fixed frequency around 32.768 kHz provided either by embedded RCO or by the external XO 32 kHz.

Main features are:

•32-bit down counter at fixed frequency 32.768 kHz

•Generate an interrupt each time the counter reaches zero

• Generate an internal reset that reboot the system if the generated interrupt is not cleared by software and a

second interrupt occurs

3.14.2 Functional description

The watchdog timer is a 32-bit down counter that divides the clock input to produce an interrupt. The divide ratio

is fully programmable and controls the interrupt interval, which can be calculated as:

Interrupt interval = (WDT_LOAD + 1) / (clock frequency in Hz).

The table below shows examples of WDT_LOAD values.

Table 165. Watchdog interrupt interval

WDT_LOAD Interrupt interval (ms)

4294967295 131072000

65535 2000

32767 1000

4095 125

127 3.90625

63 1.953125

1 0.0610

A watchdog interrupt is generated each time the counter reaches zero. The counter is then reloaded with the

content of the WDT_LR register. The interrupt status should be cleared by writing to the interrupt clear register.

When the interrupt is cleared, the counter is reloaded with the WDT_LOAD value. If the interrupt status is not

cleared and a new interrupt is generated, then a watchdog Reset is generated, rebooting the system.

The watchdog interrupt and Reset generation can be enabled or disabled as required by the system using

the relevant bits in the control register. When the interrupt generation is disabled the watchdog counter is also

stopped, and when the interrupt is enabled the counter will start from the programmed value, not the last-count

value.

Write access to the registers within the watchdog timer can be disabled in the watchdog lock register. Writing

a value of 0x1ACC_E551 to this WDT_LOCK register allows write access to all other registers; writing any

other value disables write access. This feature is included to allow some protection against software that might

otherwise disable the watchdog functionality.

3.14.3 Watchdog registers

WDG peripheral base address (WDG_BASE_ADDR) 0x40700000.

Table 166. WDG registers

Address offset Name RW Reset Description

0x00 LR RW 0xFFFFFFFF Watchdog load register. Refer to the detailed description below.

0x04 VAL R 0xFFFFFFFF Watchdog value register. Refer to the detailed description below.

0x08 CR RW 0x00000000 Watchdog control register. Refer to the detailed description below.

0x0C ICR RW 0x00000000 Watchdog interrupt clear register. Refer to the detailed description below.

0x10 RIS R 0x00000000 Watchdog raw interrupt status register. Refer to the detailed description

below.

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Address offset Name RW Reset Description

0x14 MIS R 0x00000000 Watchdog masked interrupt status register. Refer to the detailed

description below.

0xC00 LOCK RW 0x00000000 Watchdog Lock register. Refer to the detailed description below.

Table 167. WDG - LR register description: address offset WDG_BASE_ADDR+0x00

Bit Field name Reset RW Description

31:0 LOAD 0xFFFFFFFF RW

Watchdog load value. Value from which the counter is to decrement. When

this register is written to, the count is immediately restarted from the new

value.

Table 168. WDG - VAL register description: address offset WDG_BASE_ADDR+0x04

Bit Field name Reset RW Description

31:0 WDTVAL 0xFFFFFFFF R Watchdog current value. When read, returns the current value of the

decrementing watchdog counter. A write has no effect.

Table 169. WDG - CR register description: address offset WDG_BASE_ADDR+0x08

Bit Field name Reset RW Description

0 INTEN 0x0 RW

Watchdog interrupt enable. Enable the interrupt event:

0: watchdog interrupt is disabled.

1: watchdog interrupt is enabled.

1 RESEN 0x0 RW

Watchdog reset enable. Enable the watchdog reset output:

0: watchdog reset is disabled.

1: watchdog reset is enabled.

31:2 RESERVED 0x0 RW RESERVED

Table 170. WDG - ICR register description: address offset WDG_BASE_ADDR+0x0C

Bit Field name Reset RW Description

31:0 WDTICLR 0x0 RW

Watchdog interrupt clear:

Writing any value will clear the watchdog interrupt and reloads the counter

from the LR register.

A read returns zero.

Table 171. WDG - RIS register description: address offset WDG_BASE_ADDR+0x10

Bit Field name Reset RW Description

0 RIS 0x0 R

Watchdog raw interrupt status bit. Reflects the status of the interrupt status

from the watchdog:

0: watchdog interrupt is not active.

1: watchdog interrupt is active.

Read-only bit. A write has no effect.

31:1 RESERVED 0x0 R RESERVED

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Table 172. WDG - MIS register description: address offset WDG_BASE_ADDR+0x14

Bit Field name Reset RW Description

0 MIS 0x0 R

Watchdog masked interrupt status bit. Masked value of watchdog interrupt

status:

0: watchdog interrupt is not active.

1: watchdog interrupt is active.

Read-only bit. A write has no effect.

31:1 RESERVED 0x0 R RESERVED

Table 173. WDG - LOCK register description: address offset WDG_BASE_ADDR+0xC00

Bit Field name Reset RW Description

31:0 LOCKVAL 0x0 RW

Watchdog lock value. When read, returns the lock status:

0: Write access to all watchdog other registers is enabled.

1: Write access to all watchdog other registers is disabled.

When written, allows enabling or disabling write access to all other watchdog

registers:

Writing 0x1ACCE551: Write access to all other registers is enabled.

Writing any other value: Write access to all other registers is disabled.

Note: All RESERVED fields inside registers must always be written with their default value.

3.15 RTC

3.15.1 Introduction

The RTC timer can be used to provide an interrupt at regular time intervals. It generates an interrupt signal when

it reaches zero after decrementing for a programmed number of cycles of the real-time clock input. The RTC timer

can restart automatically from a load value when reaching zero if the auto restart mode is enabled, or it can stop

when it reaches zero.

The RTC is clocked by the 32 kHz clock and is switched off in low-power modes which prevents this timer to be

used for wake-up events.

3.15.2 Functional description

The RTC peripheral can be used either as real-time clock timer or as real-time clock watch.

3.15.2.1 Real-time clock timer

The real-time clock timer (RTC timer) can be used to provide an interrupt at regular time intervals.

The RTC timer can restart automatically from a load value when reaching zero if the auto restart mode is enabled,

or it can stop when it reaches zero.

The RTC timer has the following features:

• 32-bit down-counter.

• Interrupt generation when timer reaches zero.

• Start, auto restart (after counts to zero) and stop capability.

• On-the-fly register read and write access.

• 1/32 kHz minimum period.

• Multiple modes: periodic interrupt and single interrupt generation.

• Capability to switch between two load values in periodic mode. The timer reloads alternatively from one load

value to the other and the down-counter starts decrementing every 31.25 μs (on average).

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The RTC timer is a 32-bit free-running counter, clocked by the 32 kHz clock signal (from an embedded 32 kHz

RC), that works in two modes: periodic and one-shot.

Table 174. RTC modes

RTTOS bit Mode Description

0b Periodic The counter generates an interrupt at a constant interval, reloading a load value after wrapping past

zero. There are two load values: RTC_TLR1 for pattern value 0 and RTC_TLR2 for pattern value 1.

1b One-shot

The counter generates an interrupt once. When the counter reaches zero, it halts until the user

restarts it by: setting bit RTTEN in the RTC_TCR register of writing a new value to the load register

RTC_TLR1

The RTC timer load registers define the values from which the counter restarts alternatively.

In periodic mode, the timer must be stopped by the software before writing to a load register. The counter loads a

value from RTC_TLR1 or from RTC_TLR2, depending on the value of the current pattern value that crosses the

pattern register to decide after each interrupt generation, which value to load. The number of pattern bits to be

crossed periodically (from the 128 bits) is specified in RTC_TCR [10:4]. This process offers the possibility to have

better precision of the average tick period.

In one-shot mode, the timer stops when it reaches zero, but the software can also stop it. Once the counter

is halted, the load registers (RTC_TLR1, RTC_TLR2) can be written and the counter considers the new written

value. After a write, RTTEN (RTC_TCR) is set if the timer is in self-start mode.

Note: Writing to RTC_TLR1 or RTC_TLR2 has no effect when the counter is running (the registers contents are not

changed).

Note: Two consecutive write operations to the RTC_TCR register must be separated by at least 3 times the low speed

clock period plus twice the system clock period. This time is about 140 us. If this time is not satisfied, the last

written value cannot be guaranteed. The software can read back the RTC_TCR register value after at least 1

period of the low speed clock.

3.15.2.2 Real-time clock watch

The RTC clock watch consists of two counters and two alarm registers that have the following features:

•Two counters:

– Counts seconds, minutes, hours, days of the week, days of the month.

– Counts years.

• Two alarm registers:

– To trigger an interrupt at exact date and time.

The clock watch counters are split in two registers:

The RTC_CWDR register that holds:

• Seconds on six bits. Valid values are 0 to 59. (60, 61, 62 and 63 are invalid values, programming the

RTC_CWDR with these values leads to unpredictable behavior.) The seconds are incremented on the

CLK1HZ clock rate.

• Minutes on six bits. Valid values are 0 to 59 (60, 61, 62 and 63 are invalid values, programming the

RTC_CWDR with these values leads to unpredictable behavior.)

• Hours on five bits. Valid values are 0 to 23 (24 to 31 are invalid values, programming the RTC_CWDR with

these values leads to unpredictable behavior.)

• The day of the week on three bits. Valid values are 1 (Sunday) to 7 (Saturday) (0 is an invalid value,

programming the RTC_CWDR with this value leads to unpredictable behavior.)

• The day of the month on five bits. Valid values are 1 to 31 for January, March, May, July, August, October

and December, 1 to 30 for April, June, September, and November, 1 to 29 for February on leap years, or 1

to 28 for February on non-leap years. All other values are invalid values. Programming the RTC_CWDR with

these values leads to unpredictable behavior.)

• The month on four bits. Valid values are 1 (January) to 12 (December). 0, 13, 14 and 15 are invalid values,

programming the RTC_CWDR with these values leads to unpredictable behavior.

The RTC_CWYR register holds:

• The year, from 0 to 4096

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The clock watch time and date can be changed by writing new settings in the RTC_CWDLR and RTC_CWYLR

load registers. The new setting is transferred to the clock watch counters on the next CLK1HZ rising edge after

the RTC_CWDLR register has been written.

After each increment of the clock watch counters, the RTC_CWDR and RTC_CWYR registers are compared to

the clock watch match registers, RTC_CWDMR and RTC_CWYMR.

If both pairs of registers match, the internal interrupt signal RTCWINTR is raised.

3.15.2.3 RTC interrupts

The RTC generates two internal interrupt signals:

•RTCINTR: raised when the two clock watch counter registers (RTC_CWDR and RTC_CWYR) match the two

clock watch alarm registers (RTC_CWDMR and RTC_CWYMR). Some bit-fields can be ‘don’t care’ during

the comparison if a zero value is used for year, month, day of month and day of week. The software must

clear this interrupt by writing 1 in the bit RTCCWIC of RTC_ICR register.

• RTTINTR: raised when the full 32-bit down-counter RTC_TDR reaches zero and is only cleared by writing

1 in the bit RTTIC of the RTC_ICR register. The most significant carry bit of the counter detects the counter

reaches zero. The software must clear this interrupt by writing 1 in the bit RTCTIC of the RTC_ICR register.

Each individual interrupt can be masked by writing 0b to its corresponding interrupt mask set/clear bit in the

RTC_IMSC register. Both the raw interrupt status (prior to masking) and the final interrupt status (after masking)

for each individual interrupt signal can be read from the RTC_RIS and RTC_MIS status registers.

The RTC delivers also a single combined interrupt signal, RTUINTR. This interrupt line is the logical OR of the

both internal interrupt signals described above and is the signal connected to the processor interrupt line.

3.15.3 RTC registers

RTC peripheral base address (RTC_BASE_ADDR) 0x40F00000.

Table 175. RTC registers

Address offset Name RW Reset Description

0x00 CWDR R 0x02120000 Clockwatch data register. Refer to the detailed description below.

0x04 CWDMR RW 0x00000000 Clockwatch data match register. Refer to the detailed description below.

0x08 CWDLR RW 0x00000000 Clockwatch data load register. Refer to the detailed description below.

0x0C CWYR R 0x00002000 Clockwatch year register. Refer to the detailed description below.

0x10 CWYMR RW 0x00002000 Clockwatch year match register. Refer to the detailed description below.

0x14 CWYLR RW 0x00000000 Clockwatch year load register. Refer to the detailed description below.

0x18 CTCR RW 0x00007FFF Control trim and counter register. Refer to the detailed description below.

0x1C IMSC RW 0x00000000 RTC interrupt mask register. Refer to the detailed description below.

0x20 RIS R 0x00000000 RTC raw interrupt status register. Refer to the detailed description below.

0x24 MIS R 0x00000000 RTC masked interrupt status register. Refer to the detailed description

below.

0x28 ICR W 0x00000000 RTC interrupt clear register. Refer to the detailed description below.

0x2C TDR R 0xFFFFFFFF RTC timer load value

0x30 TCR RW 0x00000000 RTC timer control register. Refer to the detailed description below.

0x34 TLR1 RW 0x00000000 RTC timer first load register

0x38 TLR2 RW 0x00000000 RTC timer second load Register

0x3C TPR1 RW 0x00000000 RTC timer pattern register (pattern[31:0])

0x40 TPR2 RW 0x00000000 RTC timer pattern register (pattern[63:32])

0x44 TPR3 RW 0x00000000 RTC timer pattern register (pattern[95:64])

0x48 TPR4 RW 0x00000000 RTC timer pattern register (pattern[127:96])

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Address offset Name RW Reset Description

0x4C TIN R 0x00000000 RTC timer interrupt number register

Table 176. RTC - CWDR register description: address offset RTC_BASE_ADDR+0x00

Bit Field name Reset RW Description

5:0 CWSEC 0x0 R RTC clockwatch second value. Clockwatch seconds: 0 to 59 (max. 0x3B).

11:6 CWMIN 0x0 R RTC clockwatch minute value. Clockwatch seconds: 0 to 59 (max. 0x3B).

16:12 CWHOUR 0x0 R RTC clockwatch hour value. Clockwatch seconds: 0 to 23 (max. 0x17).

19:17 CWDAYW 0x1 R

RTC clockwatch day of week value. Clockwatch day of week:

001b: Sunday.

010b: Monday.

011b: Tuesday.

100b: Wednesday.

101b: Thursday.

110b: Friday.

111b: Saturday.

24:20 CWDAYM 0x1 R

RTC clockwatch day of month value: 1 to 28/29/30 or 31. Range of value to

program depends on the month:

1 to 28: February month, non-leap year.

1 to 29: February month, leap year.

1 to 30: April, June, September, November month.

1 to 31: January, March, May, July, August, October, December month.

28:25 CWMONTH 0x1 R

RTC clockwatch month value:

0001b: January.

...

1100: December.

31:29 RESERVED 0x0 R RESERVED

Table 177. RTC - CWDMR register description: address offset RTC_BASE_ADDR+0x04

Bit Field name Reset RW Description

5:0 CWSECM 0x0 RW

RTC clockwatch second match value:

00 0000 to 11 1011: (0 to 59 or 0x00 to 0x3B) clockwatch seconds.

11 1100 to 11 1111 - (60 to 63 or 0x3C to 0x3F).

Non-valid data, match never occurs.

11:6 CWMINM 0x0 RW

RTC clockwatch minute match value:

00 0000 to 11 1011: (0 to 59 or 0x00 to 0x3B) clockwatch minutes.

11 1100 to 11 1111 - (60 to 63 or 0x3C to 0x3F).

Non-valid data, match never occurs.

16:12 CWHOURM 0x0 RW

RTC clockwatch hour match value:

00000b to 10111b: (0 to 23 or 0x00 to 0x17) hour match value.

11000b to 11111b - (24 to 31 or 0x18 to 0x1F).

Non-valid data, match never occurs.

19:17 CWDAYWM 0x0 RW RTC clockwatch day of week match value:

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Bit Field name Reset RW Description

000b: day of week does not care in the comparison. (Default value after

PORn).

001b to 111b: (1 to 7) day of week match value.

24:20 CWDAYMM 0x0 RW

RTC clockwatch day of month match value:

0000b: (month does not care in the comparison. Default value after PORn).

1 to 31: day of month match value.

28:25 CWMONTHM 0x0 RW

RTC clockwatch month match value:

0000b: (day of month does not in the comparison. Default value after PORn).

0001b to 1100b: (1 to 12) month match value.

1101b (13, 0xD) to 1111b (0xF) non-valid data, match never occurs.

31:29 RESERVED 0x0 RW RESERVED

Table 178. RTC - CWDLR register description: address offset RTC_BASE_ADDR+0x08

Bit Field name Reset RW Description

5:0 CWSECL 0x0 RW RTC clockwatch second load value. Clockwatch seconds from 0 to 59 (0x3B).

Other values must not be used.

11:6 CWMINL 0x0 RW RTC clockwatch minute load value. Clockwatch minutes from 0 to 59 (0x3B).

Other values must not be used.

16:12 CWHOURL 0x0 RW RTC clockwatch hour load value. Clockwatch hours from 0 to 23 (0x17). Other

values must not be used.

19:17 CWDAYWL 0x0 RW

RTC clockwatch day of week load value. Clockwatch day of week:

000b: Must not be used.

001b: Sunday.

010b: Monday.

011b: Tuesday.

100b: Wednesday.

101b: Thursday.

110b: Friday.

111b: Saturday.

24:20 CWDAYML 0x0 RW

RTC clockwatch day of month load value. 1 to 28/29/30 or 31 depending on

month:

1 to 28: February month, non-leap year.

1 to 29: February month, leap year.

1 to 30: April, June, September, November month.

1 to 31: January, March, May, July, August, October, December month.

Other values must not be used.

28:25 CWMONTHL 0x0 RW

RTC clockwatch month load value:

0001b: January.

...

1100: December.

Other values must not be used.

31:29 RESERVED 0x0 RW RESERVED

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Table 179. RTC - CWYR register description: address offset RTC_BASE_ADDR+0x0C

Bit Field name Reset RW Description

13:0 CWYEAR 0x2000 R RTC clockwatch year value. Clockwatch year, in BCD format is from 0 to 4096.

31:14 RESERVED 0x0 R RESERVED

Table 180. RTC - CWYMR register description: address offset RTC_BASE_ADDR+0x10

Bit Field name Reset RW Description

13:0 CWYEARM 0x2000 RW RTC clockwatch year match value. Clockwatch year match value is in BCD

format from 0 to 4096.

31:14 RESERVED 0x0 RW RESERVED

Table 181. RTC - CWYLR register description: address offset RTC_BASE_ADDR+0x14

Bit Field name Reset RW Description

13:0 CWYEARL 0x0 RW RTC clockwatch year load value. Clockwatch year load value is in BCD format

from 0 to 4096.

31:14 RESERVED 0x0 RW RW RESERVED

Table 182. RTC - CTCR register description: address offset RTC_BASE_ADDR+0x18

Bit Field name Reset RW Description

14:0 CKDIV 0x7FFF RW

Clock divider factor. This value plus one represents the integer part of the

CLK32K clock divider used to produce the reference 1 Hz clock.

0x000: CLK1HZ clock is similar to CLK32K for RTC timer and stopped for RTC

clockwatch.

0x0001: 2 CLK32K clock cycles per CLK1HZ clock cycle.

...

0x7FFF: 32768 CLK32K clock cycles per CLK1HZ clock cycle (default value

after PORn Reset).

...

0xFFFF: CLK32K clock cycles per CLK1HZ clock cycle.

Writing to this bit-field is disregarded if CWEN = 1. A read returns the value of

the CKDIV bit-field.

15 RESERVED 0x0 RW RESERVED

25:16 CKDEL 0x0 RW

Trim delete count. This value represents the number of CLK32K clock pulses

to delete every 1023 CLK32K clock cycles to get a better reference 1 Hz clock

for incrementing the RTC counter.

0x000: No CLK32K clock cycle is deleted every 1023 CLK1HZ clock cycles

(default value after PORn Reset).

0x001: 1 CLK32K clock cycle is deleted every 1023 CLK1HZ clock cycles.

...

0x3FF: 1023 CLK32K clock cycles are deleted every 1023 CLK1HZ clock

cycles.

Writing to this bit-field is disregarded if CWEN = 1. A read returns the value of

the CKDEL bit-field.

26 CWEN 0x0 RW

Clockwatch enable bit. When set to 1, the clockwatch is enabled. Once it is

enabled, any write to this register has no effect until a Power-On-Reset. A read

returns the value of the CWEN bit value.

31:27 RESERVED 0x0 RW RESERVED

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Table 183. RTC - IMSC register description: address offset RTC_BASE_ADDR+0x1C

Bit Field name Reset RW Description

0 WIMSC 0x0 RW

RTC clock watch interrupt enable bit:

When set to 0, clears the interrupt mask (default after PORn Reset). The

interrupt is disabled.

When set to 1, the interrupt for RTC clockwatch interrupt is enabled.

1 TIMSC 0x0 RW

RTC timer interrupt enable bit:

When set to 0, sets the mask for RTC timer interrupt (default after PORn reset).

The interrupt is disabled.

When set to 1, clears this mask and enables the interrupt.

31:2 RESERVED 0x0 RW RESERVED

Table 184. RTC - RIS register description: address offset RTC_BASE_ADDR+0x20

Bit Field name Reset RW Description

0 WRIS 0x0 R RTC clock watch raw interrupt status bit. Gives the raw interrupt state (prior to

masking) of the RTC clock watch interrupt.

1TRIS 0x0 R RTC timer raw interrupt status bit. Gives the raw interrupt state (prior to

masking) of the RTC timer interrupt.

31:2 RESERVED 0x0 R RESERVED

Table 185. RTC - MIS register description: address offset RTC_BASE_ADDR+0x24.

Bit Field name Reset RW Description

0 WMIS 0x0 R RTC clock watch interrupt status bit. Gives the masked interrupt status (after

masking) of the RTC clock watch interrupt WINTR.

1TMIS 0x0 R RTC timer interrupt status bit. Gives the masked interrupt status (after masking)

of the RTC timer interrupt TINTR.

31:2 RESERVED 0x0 R RESERVED

Table 186. RTC - ICR register description: address offset RTC_BASE_ADDR+0x28

Bit Field name Reset RW Description

0 WIC 0x0 W

RTC clock watch interrupt clear register bit. Clears the RTC clock watch

interrupt WINTR.

0: No effect.

1: Clears the interrupt.

1TIC 0x0 W

RTC timer interrupt clear register bit. Clears the RTC timer interrupt TINTR.

0: No effect.

1: Clears the interrupt.

31:2 RESERVED 0x0 W RESERVED

Table 187. RTC – TDR register description: address offset RTC_BASE_ADDR+0x2C

Bit Field name Reset RW Description

31:0 TDR 0xFFFFFFFF R RTC time load value.

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Table 188. RTC - TCR register description: address offset RTC_BASE_ADDR+0x30

Bit Field name Reset RW Description

0 OS 0x0 RW

RTC Timer one shot count.

0: Periodic mode (default). When reaching zero, the RTC timer raises its

interrupt and is reloaded from the LD content.

1: One-shot mode. When reaching zero, the RTC timer raise its interrupt

and stops.

1 EN 0x0 RW

RTC Timer enable bit.

0: The RTC timer is stopped on the next CLK32K cycle.

1: The RTC timer is enabled on the next CLK32K cycle.

When the RTC timer is stopped, the content of the counter is frozen. A

read returns the value of the EN bit. This bit set by hardware when the

TLR register is written to while the counter is stopped. When the device

is active, this bit is cleared by hardware when the counter reaches zero in

one-shot mode.

2 S 0x0 RW

RTC Timer self start bit. When written to 1b, each write in a load register

or a pattern will set EN to 1b, so, start the counter in the next CLK32K

cycle.

3 RESERVED 0x0 RW RESERVED

10:4 SP 0x0 RW RTC Timer Pattern size. Number of pattern bits crossed by the pointer. It

defines the useful pattern size.

11 CLK 0x0 RW

RTC Timer clock.

0: The RTC timer is clocked by CLK32K.

1: The RTC timer is clocked by the trimmed clock.

12 BYPASS_GATED 0x0 RW

Enable or disable the internal clock gating:

0: The internal clock gating is activated.

1: No clock gating, clock is always enabled.

31:13 RESERVED 0x0 RW RESERVED

Table 189. RTC – TLR1 register description: address offset RTC_BASE_ADDR+0x34

Bit Field name Reset RW Description

31:0 TLR1 0x00000000 RW RTC timer first load value.

Table 190. RTC – TLR2 register description: address offset RTC_BASE_ADDR+0x38

Bit Field name Reset RW Description

31:0 TLR2 0x00000000 RW RTC timer second load value.

Table 191. RTC – TPR1 register description: address offset RTC_BASE_ADDR+0x3C

Bit Field name Reset RW Description

31:0 TPR1 0x00000000 RW RTC timer pattern register (pattern[31:0]).

Table 192. RTC – TPR2 register description: address offset RTC_BASE_ADDR+0x40

Bit Field name Reset RW Description

31:0 TPR2 0x00000000 RW RTC timer pattern register (pattern[63:32]).

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Table 193. RTC – TPR3 register description: address offset RTC_BASE_ADDR+0x44

Bit Field name Reset RW Description

31:0 TPR3 0x00000000 RW RTC timer pattern register (pattern[95:64]).

Table 194. RTC – TPR4 register description: address offset RTC_BASE_ADDR+0x48

Bit Field name Reset RW Description

31:0 TPR4 0x00000000 RW RTC timer pattern register (pattern[127:96]).

Table 195. RTC – TIN register description: address offset RTC_BASE_ADDR+0x4C

Bit Field name Reset RW Description

31:0 TIN 0x00000000 R RTC timer interrupt number register.

Note: All RESERVED fields inside registers must always be written with their default value.

3.16 RNG

3.16.1 Introduction

The RNG is a real random number generator based on a continuous analog noise that provides a 16-bit value to

the host when read.

3.16.2 Functional description

The peripheral is normally used by the Bluetooth Stack, but the user can read the random value at any time by

accessing the register VAL. The RNG peripheral is addressed through the AHB, so the access must be at 32-bit,

otherwise hard fault is generated on Cortex M0.

The minimum period between two consecutive random numbers is about 1.25 µs.

3.16.3 RNG registers

RNG peripheral base address (RNG_BASE_ADDR) 0xB0000000

Table 196. RNG registers

Address offset Name RW Reset Description

0x00 CR RW 0x00000000 RNG configuration register. Refer to the detailed description below.

0x04 SR R 0x00000000 RNG status register. Refer to the detailed description below.

0x08 VAL R 0x00000000 RNG 16-bit random value. Refer to the detailed description below.

Table 197. RNG – CR register description: address offset RNG_BASE_ADDR+0x00

Bit Field name Reset RW Description

1:0 RESERVED 0x0 RW RESERVED

2 DIS 0x0 RW

Set the state of the random number generator.

• 0: RNG is enable.

•1: RNG is disabled. The internal free-running oscillators are put in power-down

mode and the RNG clock is stopped at the input of the block.

31:3 RESERVED 0x00000000 RW RESERVED

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Table 198. RNG – SR register description: address offset RNG_BASE_ADDR+0x04

Bit Field name Reset RW Description

0 RDY 0x0 R

New random value ready.

•0: The VAL register value is not yet valid. If performing a read access to VAL,

the host will be put on hold until a random value is available.

• 1: The VAL register contains a valid random number.

This bit remains at 0 when the RNG is disabled (RNGDIS bit = 1b in CR)

31:1 RESERVED 0x00000000 R RESERVED

Table 199. RNG – VAL register description: address offset RNG_BASE_ADDR+0x08

Bit Field name Reset RW Description

15:0 RANDOM_VALUE 0x0000 R The 16-bit random value.

31:16 RESERVED 0x0000 R RESERVED

Note: All RESERVED fields inside registers must always be written with their default value.

3.17 PDM stream processor

The BlueNRG-2 integrates a digital filter for processing PDM stream coming from a digital microphone and

inputting into a GPIO pin. The BlueNRG-2 outputs a 0.8MHz or 1.6MHz signal into a GPIO pin for providing the

digital microphone with a frequency clock.

3.18 System timer (SysTick)

The BlueNRG-2 includes a system timer (SysTick) that can be polled by software or can be configured to

generate an interrupt. SysTick interrupt has its own entry in the vector table and therefore can have its own

handler.

3.19 Public key accelerator (PKA)

The public key accelerator is for the computation of cryptographic public key primitives through elliptic curve

cryptography (ECC) using a predefined prime modulus and a predefined curve.

3.19.1 PKA functional description

The PKA core is clocked by the system clock divided by two and the PKA memory is clocked by system clock.

This peripheral is addressed through the AHB, so the access must be at 32-bit or a hard fault is generated on the

Cortex M0.

The PKA works on a 1 kB dedicated RAM block located in 0xC0000400.

The main features of the PKA block are:

•elliptic curve Diffie-Hellman (ECDH) public-private key pair calculation accelerator

• based on the Montgomery method for fast modular multiplications

• built-in Montgomery domain inward and outward transformations

• AMBA AHB lite slave interface with a reduced command set

• single port internal memory available for the system when the BlueNRG-2 PKA is not using it.

The PKA and the PKA RAM are clock gated by default after reset,. so the clock must be enabled in CKGEN_SOC

before using PKA functionality.

The input data, output data and data verification result have specific locations in the PKA RAM.

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Table 200. PKA RAM data location

Parameter description PKA RAM offset address Size (words)

INPUT: ECC K value of kP 0x6C EOS(1)

INPUT: input point P, coordinate X 0x90 EOS

INPUT: input point P, coordinate Y 0xB4 EOS

OUTPUT: output point P, coordinate X 0x90 EOS

OUTPUT: output point P, coordinate Y 0xB4 EOS

OUTPUT: error value 0x00 1

1. ECC operand size

An error value of 1 indicates that input point P does not satisfy the curve equation; in this case, the computation is

very short. If the calculation returns an error value of 0, the result is valid.

The maximum length of data is calculated by:

Max. EOS = ( max_ecc_size / word_size) + 1

If ECC P256 is used, the PKA core needs an operand of 9 (256/32 + 1) words. When loading a 256-bit (8 word)

input, an additional word is requested and must be filled with zero.

The starting point P for the computation is:

•PX = (0x6B17D1F2, 0xE12C4247, 0xF8BCE6E5, 0x63A440F2, 0x77037D81, 0x2DEB33A0, 0xF4A13945,

0xD898C296)

•PY = (0x4FE342E2, 0xFE1A7F9B, 0x8EE7EB4A, 0x7C0F9E16, 0x2BCE3357, 0x6B315ECE, 0xCBB64068,

0x37BF51F5)

3.19.2 PKA registers

PKA peripheral base address (PKA_BASE_ADDR) 0xC0000000

Table 201. PKA registers

Address offset Name RW Reset Description

0x00 CSR RW 0x00000002 Command and status register

0x04 ISR RW 0x00000000 Interrupt status register

0x08 IEN RW 0x00000000 Interrupt enable register

Table 202. PKA – CSR register description: address offset PKA_BASE_ADDR+0x00

Bit Field name Reset RW Description

0 GO 0 W

PKA start processing command:

•0: has no effect.

• 1: starts the processing.

After this bitfield is set to 1, it must be written back to 0 manually.

1 READY 1 R

PKA readiness status:

• 0: the PKA is computing. It is not ready.

• 1: the PKA is ready to start a new process.

The rising edge of the READY bit set the PROC_END flag in the ISR register.

6:2 RESERVED 0x00 RW RESERVED

7 SFT_RST 0 W

PKA software reset:

•0: has no effect.

• 1: reset the PKA peripheral.

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Bit Field name Reset RW Description

After this bitfield is set to 1, it must be written back to 0 manually.

31:8 RESERVED 0x00 RW RESERVED

Table 203. PKA – ISR register description: address offset PKA_BASE_ADDR+0x04

Bit Field name Reset RW Description

0 PROC_END 0 RW

PKA process ending interrupt. When read:

• 0: no event.

•1: PKA process is ended.

When written:

• 0: no effect.

• 1: clears the PKA process ending interrupt.

After this bitfield is set to 1, it must be written back to 0 manually.

1 RESERVED 0 RW RESERVED

2 RAM_ERR 0 RW

RAM read/write access error interrupt. When read:

•0: all AHB read or write access to the PKA RAM occurred while the PKA was

stopped.

•1: All the AHB read or write accesses to the PKA RAM occurred while the PKA

was operating and using the internal RAM. These reads or writes could not

succeed as the PKA internal RAM is disconnected from the AHB bus when the

PKA is operating (READ bit low).

When written:

• 0: no effect.

• 1: clears the RAM access error interrupt.

After this bitfield is set to 1, it must be written back to 0 manually.

3 ADD_ERR 0 RW

AHB address error interrupt. When read:

•0: All AHB read or write access to the PKA RAM occurred in a mapped address

range.

•1: All the AHB read or write access to the PKA RAM occurred in an unmapped

address range.

When written:

• 0: no effect.

• 1: clears the AHB address error interrupt.

After this bitfield is set to 1, it must be written back to 0 manually.

31:4 RESERVED 0x00000000 RW RESERVED

Table 204. PKA – IEN register description: address offset PKA_BASE_ADDR+0x08

Bit Field name Reset RW Description

0PROCEND_EN 0 RW

Process ended interrupt enable.

• 0: interrupt disabled.

•1: interrupt enabled.

1 RESERVED 0 RW RESERVED

2 RAMERR_EN 0 RW

RAM access error interrupt enable.

• 0: interrupt disabled.

•1: interrupt enabled.

3 ADDERR_EN 0 RW

AHB address error interrupt enable.

• 0: interrupt disabled.

• 1: interrupt enabled.

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Bit Field name Reset RW Description

31:4 RESERVED 0 RW RESERVED

Note: All RESERVED fields inside registers must always be written with their default value.

3.20 TX/RX event alert

The BlueNRG-2 is provided with the ANATEST1 (pin 14 for QFN32 package, pin 24 for QFN48 package and pin

D4 for WCSP34 package) signal which alerts forthcoming transmission or reception event. The ANATEST1 pin

switches to high level before transmission and before reception. Then, it switches to low level at the end of the

event. The signal can be used for controlling external antenna switching and supporting coexistence with other

wireless technologies.

Note: In this mode, the DIO14 cannot be used and it must be set as default (pull-down input). This is valid for the

package QFN32 and WCSP34 only.

3.21 SWD debug feature

The BlueNRG-2 embeds the ARM serial wire debug (SWD) port. It is two pins (clock and single bi-directional

data) debug interface, providing all the debug functionality plus real-time access to system memory without

halting the processor or requiring any target resident code.

Table 205. SWD port

Pin functionality Pin name Pin description

SWCLK IO9 SWD clock signal

SWDIO IO10 SWD data signal

The Cortex-M0 subsystem of the BlueNRG-2 embeds four breakpoints and two watchpoints.

3.21.1 Debugging tips

There are certain situations where debug access is disabled and the chip cannot be accessed, including:

• application that disables debug pins

•application that set the device in sleep or standby state, in which the debug port is not powered.

These cases are common during application development and device can end up in a state where debug access

is no longer possible. To recover this situation, it is recommended to force IO7 pin high and hardware reset the

device in order to force execution of the updater code (see Section 3.23 Pre-programmed bootloader). The user

can then connect with SWD interface and erase the device Flash memory.

3.22 Bluetooth low energy radio

The BlueNRG-2 integrates an RF transceiver compliant to the Bluetooth specification and to the standard national

regulations in the unlicensed 2.4 GHz ISM band.

The RF transceiver requires very few external discrete components. It provides 96 dB link budgets with excellent

link reliability, keeping the maximum peak current below 15 mA.

In transmit mode, the power amplifier (PA) drives the signal generated by the frequency synthesizer out to the

antenna terminal through a very simple external network. The power delivered as well as the harmonic content

depends on the external impedance seen by the PA.

3.22.1 Radio operating modes

Several operating modes are defined for the BlueNRG-2 radio:

•Reset mode

•Sleep mode

• Active mode

BlueNRG-2

TX/RX event alert

DS12166 - Rev 7 page 126/169

• Radio mode

– RX mode

–TX mode

In Reset mode, the BlueNRG-2 is in ultra-low power consumption: all voltage regulators, clocks and the RF

interface are not powered. The BlueNRG-2 enters Reset mode by asserting the external Reset signal. As soon as

it is de-asserted, the device follows the normal activation sequence to transit to active mode.

In sleep mode either the low speed crystal oscillator or the low speed ring oscillator are running, whereas the high

speed oscillators are powered down as well as the RF interface. The state of the BlueNRG-2 is retained and the

content of the RAM is preserved.

While in sleep mode, the BlueNRG-2 waits until an internal timer expires and then it goes into active mode.

In active mode the BlueNRG-2 is fully operational: all interfaces, including RF, are active as well as all internal

power supplies together with the high speed frequency oscillator. The MCU core is also running.

Radio mode differs from active mode as also the RF transceiver is active and it is capable of either transmitting or

receiving.

3.23 Pre-programmed bootloader

BlueNRG-2 device has a pre-programmed bootloader supporting UART protocol with automatic baudrate

detection. Main features of the embedded bootloader are:

•Auto baudrate detection up to 460 kbps

•Flash mass erase, section erase

• Flash programming

• Flash readout protection enable/disable

The pre-programmed bootloader is an application which is stored on the BlueNRG-2 internal ROM at

manufacturing time by STMicroelectronics. This application allows upgrading the device Flash with a user

application using a serial communication channel (UART).

Bootloader is activated by hardware by forcing IO7 high during power-up or hardware Reset, otherwise,

application residing in Flash will be launched.

Note: The customer application must ensure that IO7 is forced low during power up. Bootloader protocol is described

in a separate application note.

3.24 Unique device serial number

The BlueNRG-2 device has a unique six-byte serial number stored at address 0x100007F4: it is stored as two

words (8 bytes) at addresses 0x100007F4 and 0x100007F8 with unique serial number padded with 0xAA55.

BlueNRG-2

Pre-programmed bootloader

DS12166 - Rev 7 page 127/169

4Pin description

The BlueNRG-2 comes in three package versions: WCSP34 offering 14 GPIOs, QFN32 offering 15 GPIOs

and QFN48 offering 26 GPIOs. Figure 22. BlueNRG-2 pin out top view (QFN32) shows the QFN32 pin out,

Figure 23. BlueNRG-2 pin out top view (QFN48) shows the QFN48 pin out and Figure 24. BlueNRG-2 ball out top

view (WCSP34) shows the WCSP34 ball out.

Figure 21. BlueNRG-2 pin out top view (QFN32)

GND

pad

89 10 11 12 13 14 15 16

32 31 30 29 28 27 26 25

DIO10

DIO9

DIO8

DIO7

DIO6

VBAT3

DIO5

DIO4

VBAT1

SXTAL0

SXTAL1

RF0

RF1

VBAT2

FXTAL0

FXTAL1

DIO11

TEST

DIO12

DIO13

VDD1V2

SMPSFILT2

SMPSFILT1

RSSETN

DIO3

DIO2

DIO1

DIO0

ANATEST0/DIO14

ANATEST1

ADC1

ADC2

BlueNRG-2

Pin description

DS12166 - Rev 7 page 128/169

Figure 22. BlueNRG-2 pin out top view (QFN48)

GND

pad

13 14 15 16 17 18 19 20

48 47 46 45 44 43 42 41

40 39 38 37

21 22 23 24

DIO24

DIO23

DIO22

DIO8

DIO7

DIO21

DIO6

VBAT4

RESETN

VBAT1

SXTAL0

SXTAL1

NC(open)

RF0

RF1

VBAT2

DIO25

DIO9

DIO10

VBAT3

DIO11

TEST

DIO12

DIO13

DIO4

DIO3

DIO2

DIO1

DIO17

DIO0

DIO16

DIO15

DIO5

DIO20

DIO19

DIO18

FXTAL0

FXTAL1

ADC2

ADC1

DIO14

VBAT4

ANATEST0

ANATEST1

VBAT3

VDD1V2

SMPSFILT2

SMPSFILT1

BlueNRG-2

Pin description

DS12166 - Rev 7 page 129/169

Figure 23. BlueNRG-2 ball out top view (WCSP34)

BlueNRG-2

Pin description

DS12166 - Rev 7 page 130/169

Figure 24. BlueNRG-2 ball out bottom view (WCSP34)

Table 206. Pinout description

Pins

Name I/O Description

QFN32 QFN48 WCSP34

1 46 F1 DIO10 I/O General purpose digital I/O

2 47 E1 DIO9 I/O General purpose digital I/O

3 4 D3 DIO8 I/O General purpose digital I/O

4 5 D2 DIO7/BOOT(1) I/O

Bootloader pin/

General purpose digital I/O

5 7 D1 DIO6 I/O General purpose digital I/O

6 40 A3

VBAT3 VDD Battery voltage input

- 45 -

7 9 C2 DIO5 I/O General purpose digital I/O

8 13 C3 DIO4 I/O General purpose digital I/O

9 14 B1 DIO3 I/O General purpose digital I/O

10 15 A1 DIO2 I/O General purpose digital I/O

11 16 B2 DIO1 I/O General purpose digital I/O

12 18 A2 DIO0 I/O General purpose digital I/O

DIO14 I/O General purpose digital I/O

23 ANATEST0 O Analog output

14 24 D4 ANATEST1 O Analog output

BlueNRG-2

Pin description

DS12166 - Rev 7 page 131/169

Pins

Name I/O Description

QFN32 QFN48 WCSP34

15 25 B4 ADC1 I ADC input 1

16 26 D5 ADC2 I ADC input 2

17 27 A6 FXTAL1 I 16/32 MHz crystal

18 28 B5 FXTAL0 I 16/32 MHz crystal

19 29 - VBAT2 VDD Battery voltage input

20 30 C6 RF1 I/O Antenna + matching circuit connection

21 31 D6 RF0 I/O Antenna + matching circuit connection

22 33 E4 SXTAL1 I 32 kHz crystal

23 34 E5 SXTAL0 I 32 kHz crystal

24 35 E6 VBAT1 VDD Battery voltage input

25 36 B3 RESETN I System reset

26 37 F6 SMPSFILT1 I SMPS output to external filter

27 38 F4 SMPSFILT2 I/O SMPS output to external filter/battery voltage input

28 39 F3 VDD1V2 O 1.2V digital core output

29 41 - DIO13 I/O General purpose digital I/O

30 42 F2 DIO12 I/O General purpose digital I/O

31 43 E3 TEST I Test pin put to GND

32 44 E2 DIO11 I/O General purpose digital I/O

- - A4

GND GND Ground

- - B6

- - C1

- - F5

- 20 - DIO15 I/O General purpose digital I/O

- 19 - DIO16 I/O General purpose digital I/O

- 17 - DIO17 I/O General purpose digital I/O

- 12 - DIO18 I/O General purpose digital I/O

- 11 - DIO19 I/O General Purpose Digital I/O

- 10 - DIO20 I/O General purpose digital I/O

- 6 - DIO21 I/O General Purpose Digital I/O

- 3 - DIO22 I/O General purpose digital I/O

- 2 - DIO23 I/O General purpose digital I/O

- 1 - DIO24 I/O General purpose digital I/O

- 8 -

VBAT4 VDD Battery voltage input

- 22 -

- 32 - Not connected - -

- 48 - DIO25 I/O General purpose digital I/O

1. The pin IO7/BOOT is monitored by bootloader after power-up or hardware reset and it should be low to prevent unwanted

bootloader activation.

BlueNRG-2

Pin description

DS12166 - Rev 7 page 132/169

5Memory mapping

Program memory, data memory, registers and I/O ports are organized within the same linear 4-Gbyte address

space.

The bytes are coded in memory in little Endian format. The lowest numbered byte in a word is considered the

word’s least significant byte and highest numbered byte the most significant.

The addressable memory space is divided into 16 main blocks, each 256 MB. All the memory areas that are not

allocated to on-chip memories and peripherals are considered “RESERVED”.

For the detailed mapping of an available memory and register areas, please refer to the memory map in table

below and to the register lists detailed in each of the peripheral sections.

Table 207. Memory mapping

Address Cortex-M0 address map Size Description

0x0000_0000 – 0x0000_07FF Code 2 kB ROM

0x1000_0000 – 0x1000_07FF Code 2 kB ROM

0x1004_0000 – 0x1007_FFFF Code 256 kB Flash

0x2000_0000 – 0x2000_2FFF(1) SRAM0 always on 12 kB SRAM

0x2000_3000 – 0x2000_5FFF SRAM1 switchable 12 kB SRAM

0x2000_6000 – 0x3FFF_FFFF RESERVED

0x4000_0000

APB peripheral

4 kB GPIO

0x4010_0000 4 kB Flash controller

0x4020_0000 4 kB System controller

0x4030_0000 4 kB UART

0x4040_0000 4 kB SPI

0x4050_0000 4 kB RESERVED

0x4060_0000 4 KB RESERVED

0x4070_0000 4 kB Watchdog

0x4080_0000 4 kB ADC

0x4090_0000 4 kB Clock generator

0x40A0_0000 4 kB I2C2

0x40B0_0000 4 kB I2C1 (2)

0x40C0_0000 4 kB AHB up converter

0x40D0_0000 4 kB MFT1

0x40E0_0000 4 kB MFT2

0x40F0_0000 4 kB RTC

0x4100_0000 4 kB RESERVED

0x4800_0000 4 kB BLE controller

0x4810_0000 4 kB BLE clock generator

0x5000_0000

AHB peripheral

4 kB RESERVED

0xA000_0000 4 kB DMA controller

0xB000_0000 4 kB RNG

0xC000_0000 4 kB PKA

0xC000_0400 1 kB PKA RAM

BlueNRG-2

Memory mapping

DS12166 - Rev 7 page 133/169

Address Cortex-M0 address map Size Description

0xE000_0000 – 0xE00F_FFFF Private peripheral bus 1 MB Cortex-M0 registers

0xE010_0000 – 0xEFFF_FFFF

RESERVED

256 MB RESERVED

0xF000_0000 – 0xFFFF_FFFF 256 MB RESERVED

1. 0x200000C0-0x200002CB reserved for radio controller.

2. The I²C 1 is not available in WLCSP34 package.

All the peripherals are addressed by APB, except DMA, RNG and PKA peripherals that are addressed by AHB.

The peripherals DMA, RNG and PKA that are addressed through the AHB, must be accessed only with 32-bit

accesses. Any 8-bit or 16-bit access generates an AHB error leading to a hard fault on Cortex-M0.

BlueNRG-2

Memory mapping

DS12166 - Rev 7 page 134/169

6Application circuit

The schematics below are purely indicative.

Figure 25. Application circuit: active DC-DC converter QFN32 package

Figure 26. Application circuit: non-active DC-DC converter QFN32 package

BlueNRG-2

Application circuit

DS12166 - Rev 7 page 135/169

Figure 27. Application circuit: active DC-DC converter WCSP34 package

Figure 28. Application circuit: non active DC-DC converter WCSP34 package

BlueNRG-2

Application circuit

DS12166 - Rev 7 page 136/169

Figure 29. Application circuit: active DC-DC converter QFN32 package with BALF-NRG-02D3 balun

DIO13

DIO12

DIO11

DIO0

DIO1

DIO2

DIO3

DIO10

DIO9

DIO8

DIO7

DIO6

DIO5

DIO4

ANATEST0/DIO14

ANATEST1

ADC1

ADC2 RESET

1.7 V to 3.6 V Power Supply

C15

C4C3

C18

C17

BALF-NRG-02D3

2A2 3

A1 4

XTAL2

C19

C16

C10

BlueNRG-1

DIO10

DIO9

DIO8

DIO7

DIO6

VBAT3

DIO5

DIO4

DIO3

DIO2

DIO1

DIO0

ANATEST0/DIO14

ANATEST1

ADC1

ADC2

DIO11 32

FTEST 31

DIO12 30

DIO13 29

VDD1V2 28

SMPSFILT2 27

SMPSFILT1 26

RESET 25

VBAT1 24

SXTAL0 23

SXTAL1 22

RF0 21

RF1 20

VBAT2 19

FXTAL0 18

FXTAL1 17

GND

XTAL1

C13

Table 208. External component list

Component Description

C1 Decoupling capacitor

C2 DC-DC converter output capacitor

C3 Decoupling capacitor for 1.2 V digital regulator

C4 Decoupling capacitor for 1.2 V digital regulator

C5 Decoupling capacitor

C6 32 kHz crystal loading capacitor

C7 32 kHz crystal loading capacitor

C8 RF balun/matching network capacitor

C9 RF balun/matching network capacitor

C10 RF balun/matching network capacitor

C11 RF balun/matching network capacitor

C12 RF balun/matching network capacitor

C13 RF balun/matching network capacitor

C14 RF balun/matching network capacitor

C15 Decoupling capacitor

C16 16/32 MHz crystal loading capacitor

C17 16/32 MHz crystal loading capacitor

BlueNRG-2

Application circuit

DS12166 - Rev 7 page 137/169

Component Description

C18 Decoupling capacitor

C19 DC-DC converter output capacitor

L1 32 kHz crystal filter inductor

L2 16/32 MHz crystal filter inductor

L3 RF balun/matching network inductor

L4 RF balun/matching network inductor

L5 RF balun/matching network inductor

XTAL1 32 kHz crystal (optional)

XTAL2 16/32 MHz crystal

BlueNRG-2

Application circuit

DS12166 - Rev 7 page 138/169

7Absolute maximum ratings and thermal data

Table 209. Absolute maximum ratings

Pin Parameter Value Unit

VBAT3, VBAT2, VBAT1, RESETN, SMPSFILT1,

SMPSFILT2 DC-DC converter supply voltage input and output -0.3 to +3.9 V

VDD1V2 DC voltage on linear voltage regulator -0.3 to +1.3 V

DIO0 to DIO25, TEST DC voltage on digital input/output pins -0.3 to +3.9 V

ANATEST0, ANATEST1, ADC1, ADC2 DC voltage on analog pins -0.3 to +3.9 V

FXTAL0, FXTAL1, SXTAL0, SXTAL1 DC voltage on XTAL pins -0.3 to +1.4 V

RF0, RF1 DC voltage on RF pins -0.3 to +1.4 V

TSTG Storage temperature range -40 to +125 °C

VESD-HBM Electrostatic discharge voltage ±2.0 kV

Note: Absolute maximum ratings are those values above which damage to the device may occur. Functional operation

under these conditions is not implied. All voltages are referred to GND.

Table 210. Thermal data

Symbol Parameter Value Unit

Rthj-amb Thermal resistance junction-ambient 34 (QFN32)

50 (WLCSP34) °C/W

Rthj-c Thermal resistance junction-case 2.5 (QFN32)

25 (WLCSP34) °C/W

BlueNRG-2

Absolute maximum ratings and thermal data

DS12166 - Rev 7 page 139/169

8General characteristics

Table 211. Operating conditions

Symbol Parameter Min. Typ. Max. Unit

VBAT Operating battery supply voltage 1.7 3.6 V

TAOperating Ambient temperature range -40 +105 °C

BlueNRG-2

General characteristics

DS12166 - Rev 7 page 140/169

9Electrical specifications

9.1 Electrical characteristics

Characteristics measured over recommended operating conditions unless otherwise specified. Typical value are

referred to TA = 25 °C, VBAT = 3.0 V. All performance data are referred to a 50 Ω antenna connector, via reference

design, QFN32 package version.

Table 212. Electrical characteristics

Symbol Parameter Test conditions Min. Typ. Max. Unit

Power consumption when DC-DC converter active

IBAT Supply current

Reset – 5 – nA

Standby – 500 – nA

Sleep mode: 32 kHz XO ON (24 KB retention RAM)

–

0.9

– µA

Sleep mode: 32 kHZ RO ON (24 KB retention RAM) 2.1

Active mode: CPU, Flash and RAM on – 1.9 – mA

RX – 7.7 – mA

TX +8 dBm

–

15.1

– mA

TX +4 dBm 10.9

TX +2 dBm 9

TX -2 dBm 8.3

TX -5 dBm 7.7

TX -8 dBm 7.1

TX -11 dBm 6.8

TX -14 dBm 6.6

Power consumption when DC-DC converter not active

IBATSupply current

Reset – 5 – nA

Standby – 500 – nA

Sleep mode: 32 kHz XO ON (24 KB retention RAM) – 0.9 –

µA

Sleep mode: 32 kHZ RO ON (24 KB retention RAM) – 2.1 –

Active mode: CPU, Flash and RAM on – 3.3 – mA

IBATSupply current

RX – 14.5

–

TX +8 dBm

–

28.8

TX +4 dBm 20.5

TX +2 dBm 17.2

TX -2 dBm 15.3

TX -5 dBm 14

TX -8 dBm 13

TX -11 dBm 12.3

TX -14 dBm 12

BlueNRG-2

Electrical specifications

DS12166 - Rev 7 page 141/169

Table 213. Digital I/O specifications

Symbol Test conditions Min. Typ. Max. Unit

T(RST)L 1.5 ms

TC 3.3 V

TC1 2.5 V

TC2 1.8 V

VIL 0.3*VDD V

VIH 0.65*VDD V

VOL IOL = 3 mA 0.4 V

VOH IOH = 3 mA 0.7*VDD V

IOL (low drive strength)

TC (VOL = 0.4 V) 5.6 mA

TC1 (VOL= 0.42 V) 6.6 mA

TC2 (VOL =0.45 V) 3 mA

IOL (high drive strength)

TC (VOL = 0.4 V) 11.2 mA

TC1 (VOL= 0.42 V) 13.2 mA

TC2 (VOL =0.45 V) 6 mA

IOL (Very high drive strength)

TC (VOL = 0.4 V) 16.9 mA

TC1 (VOL= 0.42 V) 19.9 mA

TC2 (VOL =0.45 V) 9.2 mA

IOH (low drive strength)

TC (VOH =2.4 V) 10.6 mA

TC1 (VOH = 1.72 V) 7.2 mA

TC2 (VOH = 1.35 V) 3 mA

IOH (high drive strength)

TC (VOH = 2.4 V) 19.2 mA

TC1 (VOH = 1.72 V) 12.9 mA

TC2 (VOH = 1.35 V) 5.5 mA

IOH (very high drive strength)

TC (VOH = 2.4 V) 29.4 mA

TC1 (VOH = 1.72 V) 19.8 mA

TC2 (VOH = 1.35 V) 8.4 mA

IPUD (current sourced/sinked from IOs with pull enabled)

Static supply 1.7 V 5 10 µA

Static supply 3.6 V 40 60 µA

9.1.1 Peripheral current consumption

Table 214. Peripheral current consumption

Peripheral

Typical consumption

VDD = 3.0 V, TA = 25 °C Unit

GPIO 11.0

μA

Flash controller 6.0

System controller 0.75

UART 77.0

SPI 41.0

Watchdog 4.0

BlueNRG-2

Electrical characteristics

DS12166 - Rev 7 page 142/169

Peripheral

Typical consumption

VDD = 3.0 V, TA = 25 °C Unit

ADC

μA

5.0

I2C1 92.0

I2C2 92.0

MFT1 7.5

MFT2 7.5

RTC 7.5

DMA 16.5

RNG 25.0

PKA 26.0

Note: The values are calculated as the increment to the current consumption when the peripheral is activated. The

peripheral is activated if the related clock is provided.

9.2 RF general characteristics

Characteristics measured over recommended operating conditions unless otherwise specified. Typical value are

referred to TA= 25 °C, VBAT =3.0 V. All performance data are referred to a 50 Ω antenna connector, via reference

design, QFN32 package version.

Table 215. RF general characteristics

Symbol Parameter Test conditions Min. Typ. Max. Unit

FREQ Frequency range 2400 – 2483.5 MHz

FCH Channel spacing – 2 – MHz

RFch RF channel center frequency 2402 – 2480 MHz

9.3 RF transmitter characteristics

Characteristics measured over recommended operating conditions unless otherwise specified. Typical value are

referred to TA = 25 °C, VBAT = 3.0 V. All performance data are referred to a 50 Ω antenna connector, via reference

design, QFN32 package version.

Table 216. RF transmitter characteristics

Symbol Parameter Test conditions Min. Typ. Max. Unit

MOD Modulation scheme GFSK

BT Bandwidth-bit period product – 0.5 –

Mindex Modulation index – 0.5 –

DR Air data rate – 1 – Mbps

PMAX Maximum output power At antenna connector – +8 +10 dBm

PRFC Minimum output power – -16.5 – dBm

PBW1M 6 dB bandwidth for modulated carrier (1

Mbps)

Using resolution bandwidth of

100 kHz 500 – – kHz

PRF1 1st adjacent channel transmit power 2 MHz Using resolution bandwidth of

100 kHz and average detector – -35 – dBm

BlueNRG-2

RF general characteristics

DS12166 - Rev 7 page 143/169

Symbol Parameter Test conditions Min. Typ. Max. Unit

PRF2 2nd Adjacent channel transmit power >3

MHz

Using resolution bandwidth of

100 kHz and average detector – -40 – dBm

ZLOAD Optimum differential load @ 2440 MHz – 25.4 + j20.8 (1) – Ω

1. Simulated value.

9.4 RF receiver characteristics

Characteristics measured over recommended operating conditions unless otherwise specified. Typical value are

referred to TA = 25 °C, VBAT =3.0 V. All performance data are referred to a 50 Ω antenna connector, via reference

design, QFN32 package version.

Table 217. RF receiver characteristics

Symbol Parameter Test conditions Min. Typ. Max. Unit

RXSENS Sensitivity BER <0.1% -88 dBm

PSAT Saturation BER <0.1% 11 dBm

zIN Input differential impedance @ 2440 MHz 25.5-j14.2 Ω

RF selectivity with BLE equal modulation on interfering signal

C/ICO-

channel Co-channel interference Wanted signal = -67 dBm, BER ≤

0.1% 6 dBc

C/I1 MHz Adjacent (+1 MHz) interference Wanted signal = -67 dBm,

BER≤0.1% 0 dBc

C/I2 MHz Adjacent (+2 MHz) interference Wanted signal = -67 dBm, BER ≤

0.1% -40 dBc

C/I3 MHz Adjacent (+3 MHz) interference Wanted signal = -67 dBm, BER ≤

0.1% -47 dBc

C/I≥4 MHz Adjacent (≥ ± 4 MHz) interference Wanted signal = -67 dBm, BER ≤

0.1% -46 dBc

C/I≥6 MHz Adjacent (≥ ± 6 MHz) interference Wanted signal= -67 dBm BER ≤

0.1% -48 dBc

C/I≥25 MHz Adjacent (≥ ±25 MHz) interference Wanted signal= -67 dBm, BER ≤

0.1% -70 dBc

C/IImage Image frequency interference

-2 MHz

Wanted signal = -67 dBm, BER ≤

0.1% -16 dBc

C/IImage±1 MHz

Adjacent (±1 MHz) interference to in-

band image frequency

-1 MHz

-3 MHz

Wanted signal = -67 dBm, BER ≤

0.1%

-23 dBc

Intermodulation characteristics (CW signal at f1, BLE interfering signal at f2)

P_IM(3) Input power of IM interferes at 3 and

6 MHz distance from wanted signal

Wanted signal = -64 dBm, BER ≤

0.1% -34 dBm

P_IM(-3) Input power of IM interferes at -3 and

-6 MHz distance from wanted signal

Wanted signal = -64 dBm, BER ≤

0.1% -48 dBm

P_IM(4) Input power of IM interferes at ±4 and

±8 MHz distance from wanted signal

Wanted signal = -64 dBm, BER ≤

0.1% -34 dBm

P_IM(5) Input power of IM interferes at ±5 and

±10 MHz distance from wanted signal

Wanted signal = -64 dBm, BER ≤

0.1% -34 dBm

BlueNRG-2

RF receiver characteristics

DS12166 - Rev 7 page 144/169

9.5 High speed crystal oscillator characteristics

Characteristics measured over recommended operating conditions unless otherwise specified. Typical value are

referred to TA = 25 °C, VBAT = 3.0 V.

Table 218. High speed crystal oscillator characteristics

Symbol Parameter Test conditions Min. Typ. Max. Unit

fNOM Nominal frequency – 16/32 – MHz

fTOL Frequency tolerance Includes initial accuracy, stability over temperature, aging

and frequency pulling due to incorrect load capacitance – – ±50 ppm

ESR Equivalent series resistance – – 100 Ω

PD Drive level – – 100 µW

9.5.1 High speed crystal oscillator

The BlueNRG-2 includes a fully integrated low power 16/32 MHz Xtal oscillator with an embedded amplitude

regulation loop. In order to achieve low power operation and good frequency stability of the XTAL oscillator,

certain considerations with respect to the quartz load capacitance C0 need to be taken into account.

Figure 31. High speed oscillator block diagram shows a simplified block diagram of the amplitude regulated

oscillator used on the BlueNRG-2.

BlueNRG-2

High speed crystal oscillator characteristics

DS12166 - Rev 7 page 145/169

Figure 30. High speed oscillator block diagram

Low power consumption and fast startup time is achieved by choosing a quartz crystal with a low load

capacitance C0. A reasonable choice for capacitor C0 is 12 pF. To achieve good frequency stability, the following

equation needs to be satisfied:

∁0=∁1

′*∁2

′

∁1+∁2(6)

Where C1’=C1+CPCB1+CPAD, C2’= C2+CPCB2+CPAD, where C1 and C2 are external (SMD) components, CPCB1

and CPCB2 are PCB routing parasites and CPAD is the equivalent small-signal pad-capacitance. The value of CPAD

is around 0.5 pF for each pad. The routing parasites should be minimized by placing quartz and C1/C2 capacitors

close to the chip, not only for an easier matching of the load capacitance C0, but also to ensure robustness

against noise injection. Connect each capacitor of the Xtal oscillator to ground by a separate vias.

BlueNRG-2

High speed crystal oscillator characteristics

DS12166 - Rev 7 page 146/169

9.6 Low speed crystal oscillator characteristics

Characteristics measured over recommended operating conditions unless otherwise specified. Typical value are

referred to TA = 25 °C, VBAT =3.0 V.

Table 219. Low speed crystal oscillator characteristics

Symbol Parameter Test conditions Min. Typ. Max. Unit

fNOM Nominal frequency – 32.768 – kHz

fTOL Frequency tolerance Includes initial accuracy, stability over temperature, aging

and frequency pulling due to incorrect load capacitance. – – ±50 ppm

ESR Equivalent series resistance – – 90 kΩ

PD Drive level – – 0.1 µW

Note: These values are the correct ones for NX3215SA-32.768 kHz-EXS00A-MU00003.

9.7 High speed ring oscillator characteristics

Characteristics measured over recommended operating conditions unless otherwise specified. Typical value are

referred to TA= 25 °C, VBAT =3.0 V.

Table 220. High speed ring oscillator characteristics

Symbol Parameter Test conditions Min. Typ. Max. Unit

fNOM Nominal

frequency – 14 – MHz

9.8 Low speed ring oscillator characteristics

Characteristics measured over recommended operating conditions unless otherwise specified. Typical value are

referred to TA = 25 °C, VBAT =3.0 V, QFN32 package version.

Table 221. Low speed ring oscillator characteristics

Symbol Parameter Test conditions Min. Typ. Max. Unit

32 kHz ring oscillator (LSROSC)

fNOM Nominal frequency – 32 – kHz

9.9 N-fractional frequency synthesizer characteristics

Characteristics measured over recommended operating conditions unless otherwise specified. Typical value are

referred to TA = 25 °C, VBAT =3.0 V, fc = 2440 MHz.

Table 222. N-Fractional frequency synthesizer characteristics

Symbol Parameter Test conditions Min. Typ. Max. Unit

PNSYNTH RF carrier phase noise

At ±1 MHz offset from carrier – -113 – dBc/Hz

At ±3 MHz offset from carrier – -119 – dBc/Hz

LOCKTIME PLL lock time – – 40 µs

TOTIME PLL turn-on / hop time Including calibration – – 150 µs

BlueNRG-2

Low speed crystal oscillator characteristics

DS12166 - Rev 7 page 147/169

9.10 Auxiliary block characteristics

Characteristics measured over recommended operating conditions unless otherwise specified. Typical values are

referenced to TA = 25 °C, VBAT =3.0 V, f_ADCclk =1 MHz. QFN32 package version.

Table 223. Auxiliary block characteristics

Symbol Parameter Test conditions Min. Typ. Max. Unit

Analog-to-digital converter (ADC)

VDDA Analog supply voltage 1.7 3.0 3.6 V

IDDA, AVG Analog supply current Average current during conversion – – 0.55 mA

VINP, iNN Input pin voltage With input attenuator -50 mV –(VBAT+50 mV) /

input attenuation V

SNR Diff Signal-to-noise ratio

Differential input, with OSR = 200,

PGA=0 dB. Sinewave with VinDC=0.6 V,

Vpeak diff = 0.85 V, Fin = 1 kHz

– 74 – dB

SNR SE 1 Signal-to-noise ratio

Single-ended input, with VREF = 0.6 V,

OSR = 200, PGA=0 dB. Sinewave with

VinDC=0.6 V, Vpeak = 0.425 V, Fin = 1

kHz

– 70 – dB

ENOB Diff Effective number of bits

Differential input, OSR = 200, PGA=0

dB. Sinewave with VinDC=0.6 V, Vpeak

diff = 0.85 V, Fin = 1 kHz

– 12 – bit

ENOB SE 1a Effective number of bits

Single-ended input, with VREF = 0.6 V,

with OSR = 200, PGA=0 dB. Sinewave

with VinDC=0.6 V, Vpeak = 0.425 V, Fin

= 1 kHz

– 8.5 – bit

ENOB SE 1b Effective number of bits

Single-ended input, with VREF = 0.6 V,

OSR = 200, PGA=0 dB. Sinewave with

VinDC=0.6 V, Vpeak = 0.15 V, Fin = 1

kHz

– 9.5 – bit

Analog temperature sensor

TRANGE Temperature range -40 – +105 °C

TERR Error in temperature -4 0 +4 °C

Battery sensor

VBLTRANGE Battery level indicator

range 1.8 3.6 V

VBLTERR Battery level indicator

error After calibration -150 150 mV

Brown-out reset (BOR)

VABOR Ascending brown-out

threshold – 1.68 1.7 V

VDBOR Descending brown-out

threshold 1.62 1.645 – V

BlueNRG-2

Auxiliary block characteristics

DS12166 - Rev 7 page 148/169

10 Package information

In order to meet environmental requirements, ST offers these devices in different grades of ECOPACK packages,

depending on their level of environmental compliance. ECOPACK specifications, grade definitions and product

status are available at: www.st.com. ECOPACK is an ST trademark.

BlueNRG-2

Package information

DS12166 - Rev 7 page 149/169

10.1 QFN32 package information

Figure 31. QFN32 (5 x 5 x 1 pitch 0.5 mm) package outline

QFN32_POA_8362854_B

BlueNRG-2

QFN32 package information

DS12166 - Rev 7 page 150/169

Table 224. QFN32 (5 x 5 x 1 pitch 0.5 mm) mechanical data

Dim.

Min. Typ. Max.

A0.80 0.85 1.00

A1 0 0.02 0.05

A3 0.20 REF

b 0.18 0.25 0.30

D 5.00 BSC

E 5.00 BSC

D2 3.2 3.70

E2 3.2 3.70

e 0.5 BSC

L 0.30 0.40 0.50

Ф 0° 14°

K 0.20

Figure 32. QFN32 (5 x 5 x 1 pitch 0.5 mm) package detail "A"

BlueNRG-2

QFN32 package information

DS12166 - Rev 7 page 151/169

10.2 QFN48 package information

Figure 33. QFN48 (|6 x 6 x 0.85 pitch 0.4 mm) package outline

BOTTOM VIEW

SIDE VIEW

Table 225. QFN48 (|6 x 6 x 0.85 pitch 0.4 mm) mechanical data

Dim.

Min. Typ. Max.

A0.8 0.85 0.9

A1 0.1

D 5.9 6 6.1

D1 4.1 4.2 4.3

E 5.9 6 6.1

E1 4.1 4.2 4.3

e 0.4

F 0.5

G 0.05

b 0.15 0.2 0.25

BlueNRG-2

QFN48 package information

DS12166 - Rev 7 page 152/169

Dim.

Min. Typ. Max.

L0.3 0.4 0.5

BlueNRG-2

QFN48 package information

DS12166 - Rev 7 page 153/169

10.3 WLCSP34 package information

Figure 34. WLCSP34 (2.66 x 2.56 x 0.5 pitch 0.4 mm) package outline

WLCSP34_POA_8165249

See Note 1

1. The corner of terminal A1 must be identified on the top surface by using a laser marking dot.

BlueNRG-2

WLCSP34 package information

DS12166 - Rev 7 page 154/169

Table 226. WLCSP34 (2.66 x 2.56 x 0.5 pitch 0.4 mm) mechanical data

Dim.

mm.

Notes

Min. Typ. Max.

A0.50

A1 0.20

b 0.27 (1)

D 2.50 2.56 2.58 (2)

D1 2.00

E 2.60 2.66 2.68 (3)

E1 2.00

e 0.40

f 0.28

g 0.33

ccc 0.05

1. The typical ball diameter before mounting is 0.25 mm.

2. D = f + D1 + f.

3. E = g + E1 + g.

BlueNRG-2

WLCSP34 package information

DS12166 - Rev 7 page 155/169

11 PCB assembly guidelines

For Flip Chip mounting on the PCB, STMicroelectronics recommends the use of a solder stencil aperture of 330 x

330 µm maximum and a typical stencil thickness of 125 µm.

Flip Chips are fully compatible with the use of near eutectic 95.8% Sn, 3.5% Ag, 0.7% Cu solder paste with

no-clean flux. ST's recommendations for Flip-Chip board mounting are illustrated on the soldering reflow profile

shown in Figure 36. Flip Chip CSP (2.71 x 2.58 x 0.5 pitch 0.4 mm) package reflow profile recommendation.

Figure 35. Flip Chip CSP (2.71 x 2.58 x 0.5 pitch 0.4 mm) package reflow profile recommendation

Table 227. Flip Chip CSP (2.71 x 2.58 x 0.5 pitch 0.4 mm) package reflow profile recommendation

Profile

Value

Typ. Max.

Temp. gradient in preheat (T = 70 - 180

°C/s 0.9 °C/s 3 °C/s

Temp. gradient (T = 200 - 225 °C) 2 °C/s 3 °C/s

Peak temp. in reflow 240 - 245 °C 260 °C

Time above 200 °C 60 s 90 s

Temp. gradient in cooling -2 to -3 °C -6 °C/s

Time from 50 to 220 °C 160 to 220 °C

Dwell time in the soldering zone (with temperature higher than 220 °C) has to be kept as short as possible to

prevent component and substrate damage. Peak temperature must not exceed 260 °C. Controlled atmosphere

(N2 or N2H2) is recommended during the whole reflow, especially above 150 °C.

Flip Chips are able to withstand three times the previous recommended reflow profile to be compatible with a

double reflow when SMDs are mounted on both sides of the PCB plus one additional repair.

A maximum of three soldering reflows are allowed for these lead-free packages (with repair step included).

The use of a no-clean paste is highly recommended to avoid any cleaning operation. To prevent any bump

cracks, ultrasonic cleaning methods are not recommended.

BlueNRG-2

PCB assembly guidelines

DS12166 - Rev 7 page 156/169

12 Ordering information

Table 228. Ordering information

Order code Package Packing

BlueNRG-232 QFN32 (5x5 mm)

Tape and reelBlueNRG-248 QFN48 (6x6 mm)

BlueNRG-234 WLCSP34

BlueNRG-2

Ordering information

DS12166 - Rev 7 page 157/169

Revision history

Table 229. Document revision history

Date Version Changes

07-Jun-2017 1 Initial release.

16-Nov-2017 2 Updated features in cover page and Section 2 BlueNRG-2 Bluetooth low energy stack.

14-Feb-2018 3 Minor text changes throughout the document.

26-Feb-2018 4 Updated Figure 31. Application circuit: active DC-DC converter QFN32 package with BALFNRG-

02D3 balun.

26-Jun-2018 5 Minor text changes throughout the document.

29-Apr-2020 6

Updated Table 207. Memory mapping, Table 16. CKGEN_SOC - CLOCK_EN register description:

address offset CKGEN_SOC_BASE_ADDR+0x20, Table 28. Impedance of the ADC pin,

Table 31. ADC - CTRL register description: address offset ADC_BASE_ADDR+0x00, Table 130. IO

functional map, Table 132. Pin characteristics, Table 153. MFT IO functions, Table 209. Absolute

maximum ratings, Table 213. Digital I/O specifications, Table 214. Peripheral current consumption,

Table 223. Auxiliary block characteristics.

Updated Section 3.3 Memories, Section 3.4.1.2 Active state, Section 3.6.2.4 ADC conversion,

Section 3.12.2.2 GPIO characteristics, Section 3.14.2 Functional description, Section 3.15.3 RTC

registers

Updated Figure 10. ADC block diagram, Figure 21. MFT mode 4 block diagram,

Figure 27. Application circuit: non-active DC-DC converter QFN32 package.

01-Dec-2020 7 Update Section Features.

BlueNRG-2

DS12166 - Rev 7 page 158/169

Contents

1Description ........................................................................3

2BlueNRG-2 Bluetooth Low Energy stack ...........................................5

3Functional details..................................................................7

3.1 Core .........................................................................7

3.2 Interrupts .....................................................................7

3.3 Memories ....................................................................8

3.4 Power management ............................................................8

3.4.1 State description .........................................................9

3.4.2 Power saving strategy....................................................10

3.4.3 System controller registers ................................................11

3.5 Clocks and reset management ..................................................13

3.5.1 Reset management......................................................15

3.5.2 Reset and wake-up reason decoding ........................................17

3.5.3 Clock and reset registers .................................................18

3.6 ADC ........................................................................21

3.6.1 Introduction ............................................................21

3.6.2 Functional overview .....................................................21

3.6.3 ADC registers ..........................................................25

3.7 DMA ........................................................................30

3.7.1 Introduction ............................................................30

3.7.2 Functional overview .....................................................30

3.7.3 DMA registers ..........................................................35

3.8 SPI .........................................................................43

3.8.1 Introduction ............................................................43

3.8.2 Functional overview .....................................................43

3.8.3 SPI registers ...........................................................47

3.9 UART.......................................................................54

3.9.1 Introduction ............................................................54

3.9.2 Functional description ....................................................54

3.9.3 UART registers .........................................................60

BlueNRG-2

Contents

DS12166 - Rev 7 page 159/169

3.10 I²C ..........................................................................72

3.10.1 Introduction ............................................................72

3.10.2 Functional description ....................................................72

3.10.3 I²C registers ...........................................................73

3.11 Flash controller ...............................................................86

3.11.1 Flash controller introduction ...............................................86

3.11.2 Flash controller functional description ........................................86

3.11.3 Flash controller registers..................................................88

3.12 GPIO........................................................................91

3.12.1 Introduction ............................................................91

3.12.2 Functional description ....................................................91

3.12.3 GPIO registers .........................................................94

3.13 MFT........................................................................100

3.13.1 MFT introduction .......................................................100

3.13.2 MFT functional description ...............................................100

3.13.3 MFT registers .........................................................108

3.14 Watchdog ...................................................................111

3.14.1 Introduction .......................................................... 111

3.14.2 Functional description ...................................................112

3.14.3 Watchdog registers .....................................................112

3.15 RTC........................................................................114

3.15.1 Introduction ...........................................................114

3.15.2 Functional description ...................................................114

3.15.3 RTC registers ......................................................... 116

3.16 RNG .......................................................................122

3.16.1 Introduction ...........................................................122

3.16.2 Functional description ...................................................122

3.16.3 RNG registers .........................................................122

3.17 PDM stream processor........................................................123

3.18 System timer (SysTick)........................................................123

3.19 Public key accelerator (PKA) ...................................................123

3.19.1 PKA functional description ...............................................123

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Contents

DS12166 - Rev 7 page 160/169

3.19.2 PKA registers .........................................................124

3.20 TX/RX event alert ............................................................126

3.21 SWD debug feature ..........................................................126

3.21.1 Debugging tips ........................................................126

3.22 Bluetooth low energy radio.....................................................126

3.22.1 Radio operating modes ..................................................126

3.23 Pre-programmed bootloader ...................................................127

3.24 Unique device serial number ...................................................127

4Pin description ................................................................. 128

5Memory mapping ............................................................... 133

6Application circuit .............................................................. 135

7Absolute maximum ratings and thermal data .................................... 139

8General characteristics ......................................................... 140

9Electrical specifications ........................................................ 141

9.1 Electrical characteristics.......................................................141

9.1.1 Peripheral current consumption ...........................................142

9.2 RF general characteristics .....................................................143

9.3 RF transmitter characteristics ..................................................143

9.4 RF receiver characteristics.....................................................144

9.5 High speed crystal oscillator characteristics ......................................145

9.5.1 High speed crystal oscillator ..............................................145

9.6 Low speed crystal oscillator characteristics .......................................147

9.7 High speed ring oscillator characteristics .........................................147

9.8 Low speed ring oscillator characteristics .........................................147

9.9 N-fractional frequency synthesizer characteristics .................................147

9.10 Auxiliary block characteristics ..................................................148

10 Package information............................................................ 149

10.1 QFN32 package information ...................................................150

10.2 QFN48 package information ...................................................152

10.3 WLCSP34 package information ................................................154

11PCB assembly guidelines ....................................................... 156

BlueNRG-2

Contents

DS12166 - Rev 7 page 161/169

12 Ordering information ........................................................... 157

Revision history ..................................................................... 158

BlueNRG-2

Contents

DS12166 - Rev 7 page 162/169

List of figures

Figure 1. BlueNRG-2 architecture..............................................................3

Figure 2. BlueNRG-2 bus architecture...........................................................4

Figure 3. BlueNRG-2 single-chip RF software layers .................................................5

Figure 4. BlueNRG-2 network processor RF software layers ...........................................6

Figure 5. BlueNRG-2 power management state machine..............................................9

Figure 6. Clock tree ...................................................................... 14

Figure 7. Reset and wake-up generation ........................................................ 15

Figure 8. BlueNRG-2 power-up sequence ....................................................... 16

Figure 9. Reset circuit ..................................................................... 17

Figure 10. ADC block diagram ................................................................ 22

Figure 11. DMA request mapping in BlueNRG-2 ................................................... 35

Figure 12. MicroWire master and slave communication ............................................... 47

Figure 13. UART character frame.............................................................. 55

Figure 14. Hardware flow control between two similar devices .......................................... 57

Figure 15. PWM signal on TnA pin ............................................................ 101

Figure 16. MFT mode 1 block diagram ......................................................... 101

Figure 17. MFT mode 1a block diagram ........................................................ 102

Figure 18. MFT mode 2 block diagram ......................................................... 104

Figure 19. MFT mode 3 block diagram ......................................................... 105

Figure 20. MFT mode 4 block diagram ......................................................... 106

Figure 21. BlueNRG-2 pin out top view (QFN32) .................................................. 128

Figure 22. BlueNRG-2 pin out top view (QFN48) .................................................. 129

Figure 23. BlueNRG-2 ball out top view (WCSP34)................................................. 130

Figure 24. BlueNRG-2 ball out bottom view (WCSP34) .............................................. 131

Figure 25. Application circuit: active DC-DC converter QFN32 package................................... 135

Figure 26. Application circuit: non-active DC-DC converter QFN32 package ............................... 135

Figure 27. Application circuit: active DC-DC converter WCSP34 package ................................. 136

Figure 28. Application circuit: non active DC-DC converter WCSP34 package .............................. 136

Figure 29. Application circuit: active DC-DC converter QFN32 package with BALF-NRG-02D3 balun .............. 137

Figure 30. High speed oscillator block diagram ................................................... 146

Figure 31. QFN32 (5 x 5 x 1 pitch 0.5 mm) package outline .......................................... 150

Figure 32. QFN32 (5 x 5 x 1 pitch 0.5 mm) package detail "A" ......................................... 151

Figure 33. QFN48 (|6 x 6 x 0.85 pitch 0.4 mm) package outline ........................................ 152

Figure 34. WLCSP34 (2.66 x 2.56 x 0.5 pitch 0.4 mm) package outline ................................... 154

Figure 35. Flip Chip CSP (2.71 x 2.58 x 0.5 pitch 0.4 mm) package reflow profile recommendation................ 156

BlueNRG-2

List of figures

DS12166 - Rev 7 page 163/169

List of tables

Table 1. BlueNRG-2 interrupt vectors ............................................................7

Table 2. Relationship between the BlueNRG-2 states and functional blocks................................. 10

Table 3. SYSTEM_CTRL registers ............................................................. 11

Table 4. SYSTEM_CTRL - WKP_IO_IS register description: address offset SYSTEM_CTRL_BASE_ADDR+0x00 ..... 11

Table 5. SYSTEM_CTRL - WKP_IO_IE register description: address offset SYSTEM_CTRL_BASE_ADDR+0x04 ...... 12

Table 6. SYSTEM_CTRL - CTRL register description: address offset SYSTEM_CTRL_BASE_ADDR+0x08 .......... 12

Table 7. SYSTEM_CTRL - SLEEPIO_OEN register description: address offset SYSTEM_CTRL_BASE_ADDR+0x0C ... 12

Table 8. SYSTEM_CTRL – SLEEPIO_OUT register description: address offset SYSTEM_CTRL_BASE_ADDR+0x10 ... 12

Table 9. SYSTEM_CTRL - SLEEPIO_DS register description: address offset SYSTEM_CTRL_BASE_ADDR+0x14..... 13

Table 10. SYSTEM_CTRL - SLEEPIO_PE register description: address offset SYSTEM_CTRL_BASE_ADDR+0x18..... 13

Table 11. AHBUPCONV registers .............................................................. 13

Table 12. BLUE_CTRL registers ............................................................... 13

Table 13. CKGEN_SOC registers............................................................... 18

Table 14. CKGEN_SOC - REASON_RST register description: address offset CKGEN_SOC_BASE_ADDR+0x08 ....... 18

Table 15. CKGEN_SOC - DIE_ID register description: address offset CKGEN_SOC_BASE_ADDR+0x1C ............ 18

Table 16. CKGEN_SOC - CLOCK_EN register description: address offset CKGEN_SOC_BASE_ADDR+0x20 ......... 19

Table 17. CKGEN_SOC - DMA_CONFIG register description: address offset CKGEN_SOC_BASE_ADDR+0x24 ....... 19

Table 18. CKGEN_SOC - JTAG_IDCODE register description: address offset CKGEN_SOC_BASE_ADDR+0x28....... 19

Table 19. CKGEN_BLE registers ............................................................... 20

Table 20. CKGEN_BLE - REASON_RST register description: address offset CKGEN_BLE_BASE_ADDR+0x08 ........ 20

Table 21. CKGEN_BLE - CLK32K_COUNT register description: address offset CKGEN_BLE_BASE_ADDR+0x0C ...... 20

Table 22. CKGEN_BLE - CLK32K_PERIOD register description: address offset CKGEN_BLE_BASE_ADDR+0x10...... 21

Table 23. CKGEN_BLE - CLK32K_FREQ register description: address offset CKGEN_BLE_BASE_ADDR+0x14 ....... 21

Table 24. CKGEN_BLE - CLK32K_IT register description: address offset CKGEN_BLE_BASE_ADDR+0x18 .......... 21

Table 25. ADC channels ..................................................................... 22

Table 26. ADC data rate ..................................................................... 22

Table 27. ADC parameter settings .............................................................. 23

Table 28. Impedance of the ADC pin ............................................................ 23

Table 29. Output data rate with microphone........................................................ 23

Table 30. ADC registers ..................................................................... 25

Table 31. ADC - CTRL register description: address offset ADC_BASE_ADDR+0x00 ........................... 26

Table 32. ADC - CONF register description: address offset ADC_BASE_ADDR+0x04 .......................... 27

Table 33. ADC - IRQSTAT register description: address offset ADC_BASE_ADDR+0x08 ........................ 28

Table 34. ADC - IRQMASK register description: address offset ADC_BASE_ADDR+0x0C ....................... 28

Table 35. ADC - IRQRAW register description: address offset ADC_BASE_ADDR+0x10 ........................ 29

Table 36. ADC - DATA_CONV register description: address offset ADC_BASE_ADDR+0x14 ..................... 29

Table 37. ADC - OFFSET register description: address offset ADC_BASE_ADDR+0x18......................... 29

Table 38. ADC - SR_REG register description: address offset ADC_BASE_ADDR+0x20 ........................ 30

Table 39. ADC - THRESHOLD_HI register description: address offset ADC_BASE_ADDR+0x24................... 30

Table 40. ADC - THRESHOLD_LO register description: address offset ADC_BASE_ADDR+0x28 .................. 30

Table 41. Programmable data width and endian behavior (when bits PINC = MINC = 1) ......................... 32

Table 42. DMA interrupt requests............................................................... 34

Table 43. DMA registers ..................................................................... 35

Table 44. DMA - ISR register description: address offset DMA_BASE_ADDR+0x00 ............................ 35

Table 45. DMA - IFCR register description: address offset DMA_BASE_ADDR+0x04 ........................... 39

Table 46. DMA_CHx registers ................................................................. 41

Table 47. DMA_CHx - CCR register description: address offset DMA_CHX_BASE_ADDR+0x00 ................... 41

Table 48. DMA_CHx - CNDTR register description: address offset DMA_CHX_BASE_ADDR+0x04 ................. 43

Table 49. DMA_CHx - CPAR register description: address offset DMA_CHX_BASE_ADDR+0x08 .................. 43

Table 50. DMA_CHx - CMAR register description: address offset DMA_CHX_BASE_ADDR+0x0C ................. 43

Table 51. SPI pin assignments................................................................. 44

Table 52. SPI clock phase and clock polarity ....................................................... 44

BlueNRG-2

List of tables

DS12166 - Rev 7 page 164/169

Table 53. SPI_OUT endianness................................................................ 45

Table 54. SPI_IN endianness ................................................................. 45

Table 55. SPI registers ...................................................................... 48

Table 56. SPI - CR0 register description: address offset SPI_BASE_ADDR+0x00 ............................. 48

Table 57. SPI - CR1 register description: address offset SPI_BASE_ADDR+0x04 ............................. 49

Table 58. SPI - DR register description: address offset SPI_BASE_ADDR+0x08 .............................. 50

Table 59. SPI - SR register description: address offset SPI_BASE_ADDR+0x0C .............................. 50

Table 60. SPI - CPSR register description: address offset SPI_BASE_ADDR+0x10 ............................ 51

Table 61. SPI - IMSC register description. Address offset SPI_BASE_ADDR+0x14. ............................ 51

Table 62. SPI - RIS register description: address offset SPI_BASE_ADDR+0x18 .............................. 52

Table 63. SPI - MIS register description: address offset SPI_BASE_ADDR+0x1C ............................. 52

Table 64. SPI - ICR register description: address offset SPI_BASE_ADDR+0x20 .............................. 52

Table 65. SPI - DMACR register description: address offset SPI_BASE_ADDR+0x24 .......................... 52

Table 66. SPI – RXFRM register description: address offset SPI_BASE_ADDR+0x28 .......................... 53

Table 67. SPI – CHN register description: address offset SPI_BASE_ADDR+0x2C ............................ 53

Table 68. SPI – WDTXF register description: address offset SPI_BASE_ADDR + 0x30.......................... 53

Table 69. SPI - ITCR register description: address offset SPI_BASE_ADDR+0x80 ............................. 53

Table 70. SPI – TDR register description: address offset SPI_BASE_ADDR+0x8C............................. 53

Table 71. RX FIFO errors .................................................................... 54

Table 72. Typical baud rates with OVSFACT = 0 .................................................... 56

Table 73. Typical baud rates with OVSFACT = 1 .................................................... 56

Table 74. Control bits to enable and disable hardware flow control ........................................ 57

Table 75. Control bits to enable and program receive software flow control .................................. 58

Table 76. Control bits to enable and program transmit software flow control.................................. 58

Table 77. UART registers .................................................................... 60

Table 78. UART - DR register description: address offset UART_BASE_ADDR+0x00 ........................... 61

Table 79. UART - RSR register description: address offset UART_BASE_ADDR+0x04.......................... 62

Table 80. UART - TIMEOUT register description: address offset UART_BASE_ADDR+0x0C...................... 62

Table 81. UART - FR register description: address offset UART_BASE_ADDR+0x18 ........................... 62

Table 82. UART - LCRH_RX register description: address offset UART_BASE_ADDR+0x1C ..................... 63

Table 83. UART - IBRD register description: address offset UART_BASE_ADDR+0x24 ......................... 64

Table 84. UART - FBRD register description: address offset UART_BASE_ADDR+0x28 ......................... 64

Table 85. UART - LCRH_TX register description: address offset UART_BASE_ADDR+0x2C...................... 64

Table 86. UART - CR register description: address offset UART_BASE_ADDR+0x30 ........................... 65

Table 87. UART - IFLS register description: address offset UART_BASE_ADDR+0x34.......................... 66

Table 88. UART - IMSC register description: address offset UART_BASE_ADDR+0x38 ......................... 67

Table 89. UART - RIS register description: address offset UART_BASE_ADDR+0x3C .......................... 68

Table 90. UART - MIS register description: address offset UART_BASE_ADDR+0x40 .......................... 68

Table 91. UART - ICR register description: address offset UART_BASE_ADDR+0x44 .......................... 69

Table 92. UART - DMACR register description: address offset UART_BASE_ADDR+0x48 ....................... 70

Table 93. UART - XFCR register description: address offset UART_BASE_ADDR+0x50 ......................... 70

Table 94. UART - XON1 register description: address offset UART_BASE_ADDR+0x54 ......................... 71

Table 95. UART - XON2 register description. Address offset UART_BASE_ADDR+0x58. ........................ 71

Table 96. UART - XOFF1 register description. Address offset UART_BASE_ADDR+0x5C. ....................... 71

Table 97. UART - XOFF2 register description. Address offset UART_BASE_ADDR+0x60. ....................... 71

Table 98. I2Cx registers ..................................................................... 74

Table 99. I2C - CR register description: address offset I2CX_BASE_ADDR+0x00 ............................. 74

Table 100. I2C - SCR register description: address offset I2CX_BASE_ADDR+0x04 ............................ 76

Table 101. I2C2 - MCR register description: address offset I2CX_BASE_ADDR+0x0C ........................... 76

Table 102. I2C - TFR register description: address offset I2CX_BASE_ADDR+0x10............................. 77

Table 103. I2C - SR register description: address offset I2CX_BASE_ADDR+0x14 ............................. 77

Table 104. I2C - RFR register description: address offset I2CX_BASE_ADDR+0x18 ............................ 78

Table 105. I2C - TFTR register description: address offset I2CX_BASE_ADDR+0x1C ........................... 79

Table 106. I2C - RFTR register description: address offset I2CX_BASE_ADDR+0x20 ........................... 79

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Table 107. I2C - DMAR register description: address offset I2CX_BASE_ADDR+0x24 ........................... 79

Table 108. I2C - BRCR register description: address offset I2CX_BASE_ADDR+0x28 ........................... 79

Table 109. I2C - IMSCR register description: address offset I2CX_BASE_ADDR+0x2C .......................... 79

Table 110. I2C - RISR register description: address offset I2CX_BASE_ADDR+0x30 ............................ 81

Table 111. I2C - MISR register description: address offset I2CX_BASE_ADDR+0x34............................ 83

Table 112. I2C - ICR register description: address offset I2CX_BASE_ADDR+0x38 ............................. 84

Table 113. I2C - THDDAT register description: address offset I2CX_BASE_ADDR+0x4C ......................... 85

Table 114. I2C - THDSTA_FST_STD register description: address offset I2CX_BASE_ADDR+0x50 ................. 85

Table 115. I2C - TSUSTA_FST_STD register description: address offset I2CX_BASE_ADDR+0x58.................. 86

Table 116. Flash commands ................................................................... 88

Table 117. Flash interface timing ................................................................ 88

Table 118. FLASH controller registers ............................................................ 88

Table 119. FLASH – COMMAND register description: address offset FLASH_BASE_ADDR+0x00................... 89

Table 120. FLASH – CONFIG register description: address offset FLASH_BASE_ADDR+0x04 ..................... 89

Table 121. FLASH - IRQSTAT register description: address offset FLASH_BASE_ADDR+0x08 ..................... 89

Table 122. FLASH - IRQMASK register description: address offset FLASH_BASE_ADDR+0x0C .................... 89

Table 123. FLASH - IRQRAW register description: address offset FLASH_BASE_ADDR+0x10 ..................... 90

Table 124. FLASH – SIZE register description: address offset FLASH_BASE_ADDR+0x14 ....................... 90

Table 125. FLASH – ADDRESS register description: address offset FLASH_BASE_ADDR+0x18 ................... 90

Table 126. FLASH – DATA0 register description: address offset FLASH_BASE_ADDR+0x40 ...................... 90

Table 127. FLASH – DATA1 register description: address offset FLASH_BASE_ADDR+0x44 ...................... 90

Table 128. FLASH – DATA2 register description: address offset FLASH_BASE_ADDR+0x48 ...................... 90

Table 129. FLASH – DATA3 register description: address offset FLASH_BASE_ADDR+0x4C ...................... 90

Table 130. IO functional map................................................................... 91

Table 131. GPIO interrupt modes................................................................ 92

Table 132. Pin characteristics .................................................................. 92

Table 133. GPIO registers..................................................................... 94

Table 134. GPIO – DATA register description: address offset GPIO_BASE_ADDR+0x00 ......................... 95

Table 135. GPIO – OEN register description: address offset GPIO_BASE_ADDR+0x04 .......................... 95

Table 136. GPIO – PE register description: address offset GPIO_BASE_ADDR+0x08 ........................... 96

Table 137. GPIO – DS register description: address offset GPIO_BASE_ADDR+0x0C ........................... 96

Table 138. GPIO – IS register description: address offset GPIO_BASE_ADDR+0x10 ............................ 96

Table 139. GPIO – IBE register description: address offset GPIO_BASE_ADDR+0x14 ........................... 96

Table 140. GPIO – IEV register description: address offset GPIO_BASE_ADDR+0x18 ........................... 96

Table 141. GPIO – IE register description: address offset GPIO_BASE_ADDR+0x1C............................ 96

Table 142. GPIO – RIS register description: address offset GPIO_BASE_ADDR+0x20........................... 97

Table 143. GPIO – MIS register description: address offset GPIO_BASE_ADDR+0x24 .......................... 97

Table 144. GPIO – IC register description: address offset GPIO_BASE_ADDR+0x28 ............................ 97

Table 145. GPIO - MODE0 register description: address offset GPIO_BASE_ADDR+0x2C ........................ 97

Table 146. GPIO – MODE1 register description: address offset GPIO_BASE_ADDR+0x30........................ 97

Table 147. GPIO – MODE2 register description: address offset GPIO_BASE_ADDR+0x34........................ 98

Table 148. GPIO – MODE3 register description: address offset GPIO_BASE_ADDR+0x38........................ 98

Table 149. GPIO – DATS register description: address offset GPIO_BASE_ADDR+0x3C ......................... 99

Table 150. GPIO – DATC register description: address offset GPIO_BASE_ADDR+0x40 ......................... 99

Table 151. GPIO - MFTX register description: address offset GPIO_BASE_ADDR+0x44 ......................... 99

Table 152. MFT modes...................................................................... 100

Table 153. MFT IO functions .................................................................. 107

Table 154. MFT interrupt functions .............................................................. 107

Table 155. MFTX registers ................................................................... 108

Table 156. MFTX – TnCNT1 register description: address offset MFTX_BASE_ADDR+0x00...................... 108

Table 157. MFTX – TnCRA register description: address offset MFTX_BASE_ADDR+0x04 ...................... 108

Table 158. MFTX – TnCRB register description: address offset MFTX_BASE_ADDR+0x08 ...................... 108

Table 159. MFTX – TnCNT2 register description: address offset MFTX_BASE_ADDR+0x0C ..................... 109

Table 160. MFTX – TnPRSC register description: address offset MFTX_BASE_ADDR+0x10 ..................... 109

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Table 161. MFTX - TnCKC register description: address offset MFTX_BASE_ADDR+0x14 ....................... 109

Table 162. MFTX - TnMCTRL register description: address offset MFTX_BASE_ADDR+0x18..................... 109

Table 163. MFTX - TNICTRL register description: address offset MFTX_BASE_ADDR+0x1C ......................111

Table 164. MFTX - TNICLR register description: address offset MFTX_BASE_ADDR+0x20 .......................111

Table 165. Watchdog interrupt interval ............................................................112

Table 166. WDG registers.....................................................................112

Table 167. WDG - LR register description: address offset WDG_BASE_ADDR+0x00 ............................113

Table 168. WDG - VAL register description: address offset WDG_BASE_ADDR+0x04 ...........................113

Table 169. WDG - CR register description: address offset WDG_BASE_ADDR+0x08............................113

Table 170. WDG - ICR register description: address offset WDG_BASE_ADDR+0x0C ...........................113

Table 171. WDG - RIS register description: address offset WDG_BASE_ADDR+0x10 ...........................113

Table 172. WDG - MIS register description: address offset WDG_BASE_ADDR+0x14 ...........................114

Table 173. WDG - LOCK register description: address offset WDG_BASE_ADDR+0xC00 ........................114

Table 174. RTC modes.......................................................................115

Table 175. RTC registers .....................................................................116

Table 176. RTC - CWDR register description: address offset RTC_BASE_ADDR+0x00 ..........................117

Table 177. RTC - CWDMR register description: address offset RTC_BASE_ADDR+0x04 .........................117

Table 178. RTC - CWDLR register description: address offset RTC_BASE_ADDR+0x08 .........................118

Table 179. RTC - CWYR register description: address offset RTC_BASE_ADDR+0x0C ..........................119

Table 180. RTC - CWYMR register description: address offset RTC_BASE_ADDR+0x10 .........................119

Table 181. RTC - CWYLR register description: address offset RTC_BASE_ADDR+0x14 .........................119

Table 182. RTC - CTCR register description: address offset RTC_BASE_ADDR+0x18 ...........................119

Table 183. RTC - IMSC register description: address offset RTC_BASE_ADDR+0x1C .......................... 120

Table 184. RTC - RIS register description: address offset RTC_BASE_ADDR+0x20 ........................... 120

Table 185. RTC - MIS register description: address offset RTC_BASE_ADDR+0x24. ........................... 120

Table 186. RTC - ICR register description: address offset RTC_BASE_ADDR+0x28 ........................... 120

Table 187. RTC – TDR register description: address offset RTC_BASE_ADDR+0x2C .......................... 120

Table 188. RTC - TCR register description: address offset RTC_BASE_ADDR+0x30 ........................... 121

Table 189. RTC – TLR1 register description: address offset RTC_BASE_ADDR+0x34 .......................... 121

Table 190. RTC – TLR2 register description: address offset RTC_BASE_ADDR+0x38 .......................... 121

Table 191. RTC – TPR1 register description: address offset RTC_BASE_ADDR+0x3C ......................... 121

Table 192. RTC – TPR2 register description: address offset RTC_BASE_ADDR+0x40 .......................... 121

Table 193. RTC – TPR3 register description: address offset RTC_BASE_ADDR+0x44 .......................... 122

Table 194. RTC – TPR4 register description: address offset RTC_BASE_ADDR+0x48 .......................... 122

Table 195. RTC – TIN register description: address offset RTC_BASE_ADDR+0x4C ........................... 122

Table 196. RNG registers .................................................................... 122

Table 197. RNG – CR register description: address offset RNG_BASE_ADDR+0x00 ........................... 122

Table 198. RNG – SR register description: address offset RNG_BASE_ADDR+0x04 ........................... 123

Table 199. RNG – VAL register description: address offset RNG_BASE_ADDR+0x08 .......................... 123

Table 200. PKA RAM data location ............................................................. 124

Table 201. PKA registers .................................................................... 124

Table 202. PKA – CSR register description: address offset PKA_BASE_ADDR+0x00........................... 124

Table 203. PKA – ISR register description: address offset PKA_BASE_ADDR+0x04 ........................... 125

Table 204. PKA – IEN register description: address offset PKA_BASE_ADDR+0x08 ........................... 125

Table 205. SWD port ....................................................................... 126

Table 206. Pinout description ................................................................. 131

Table 207. Memory mapping .................................................................. 133

Table 208. External component list ............................................................. 137

Table 209. Absolute maximum ratings ........................................................... 139

Table 210. Thermal data..................................................................... 139

Table 211. Operating conditions ............................................................... 140

Table 212. Electrical characteristics ............................................................. 141

Table 213. Digital I/O specifications ............................................................. 142

Table 214. Peripheral current consumption ........................................................ 142

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Table 215. RF general characteristics............................................................ 143

Table 216. RF transmitter characteristics ......................................................... 143

Table 217. RF receiver characteristics ........................................................... 144

Table 218. High speed crystal oscillator characteristics................................................ 145

Table 219. Low speed crystal oscillator characteristics ................................................ 147

Table 220. High speed ring oscillator characteristics.................................................. 147

Table 221. Low speed ring oscillator characteristics .................................................. 147

Table 222. N-Fractional frequency synthesizer characteristics ........................................... 147

Table 223. Auxiliary block characteristics ......................................................... 148

Table 224. QFN32 (5 x 5 x 1 pitch 0.5 mm) mechanical data ............................................ 151

Table 225. QFN48 (|6 x 6 x 0.85 pitch 0.4 mm) mechanical data ......................................... 152

Table 226. WLCSP34 (2.66 x 2.56 x 0.5 pitch 0.4 mm) mechanical data .................................... 155

Table 227. Flip Chip CSP (2.71 x 2.58 x 0.5 pitch 0.4 mm) package reflow profile recommendation ................. 156

Table 228. Ordering information................................................................ 157

Table 229. Document revision history ............................................................ 158

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