Atmel-7766JS-USB-ATmega16U4/32U4-Datasheet_04/2016
Features
•High Performance, Low Power AVR® 8-Bit Microcontroller
•Advanced RISC Architecture
– 135 Powerful Instructions – Most Single Clock Cycle Execution
– 32 x 8 Genera l Pur pos e Worki ng Registers
– Fully Static Operation
– Up to 16 MIPS Throughput at 16MHz
– On-Chip 2-cycle Multi pl ier
•Non-volatile Program and Data Memories
– 16/32KB of In-System Self-Programmabl e Flash
– 1.25/2.5KB Internal SRAM
– 512Bytes/1KB Internal EEPROM
– Write/Erase Cycles: 10,000 Flash/100,000 EEPROM
– Data retention: 20 years at 85C/ 100 years at 25C(1)
– Optional Boot Code Section with Indepe nd e nt Lo ck Bits
In-System Programming by On-chip Boot Progra m
True Read-While-Write Op eratio n
Parts using externa l XTAL cl oc k are pre -programed with a default USB bootloade r
– Programming Lock for Software Security
•JTAG (IEEE® std. 1149.1 compliant) Interface
– Boundary-scan Capabilities According to the JTAG Standard
– Extensive On-c hip Debug Support
– Programming of Flash, EEPROM, Fuses, and Lock Bits through the JTAG Interface
•USB 2.0 Full-speed/Low Speed Device Module with Interrupt on Transfer Completion
– Complies fully with Universal Serial Bus Specification Rev 2.0
– Supports data transfer rates up to 12Mbit/s and 1.5Mbit/s
– Endpoint 0 for Control Transfers: up to 64-bytes
– Six Programmab le Endpoints with IN or Out Directions and with Bulk, Interrup t or
Isochronous Transfers
– Configurable Endpoints size up to 256 bytes in double bank mode
– Fully independent 832 bytes USB DPRAM for endpoint memory allocation
– Suspend/Resume Interrupts
– CPU Reset possible on USB Bus Reset detection
– 48MHz from PLL for Full-speed Bus Operation
– USB Bus Connection/Disconnection on Microcontroller Request
– Crystal-less operation for Low Speed mode
•Peripheral Features
– On-chip PLL for USB and High Speed Timer: 32 up to 96MHz operation
– One 8-bit Timer/Counter with Separate Prescaler and Compare Mode
ATmega16U4/ATmega32U4
8-bit Microcontroller with 16/32K bytes of ISP Flash and
USB Controller
DATASHEET SUMMARY
ATmega16U4/32U4 [DATASHEET]
Atmel-7766JS-USB-ATmega16U4/32U4-Datasheet_04/2016
2
– Two 16-bit Timer/Counter with Separate Prescaler, Compare- and Capture Mode
– One 10-bit High-Speed Timer/Counter with PLL (64MHz) and Compare Mode
– Four 8-bit PWM Channels
– Four PWM Channels with Programmabl e Resolution from 2 to 16 Bits
– Six PWM Channels for High Speed Operation, with Programmable Resolution from 2 to 11 Bits
– Output Compare Modulator
– 12-channels, 10-bit ADC (features Differential Channels with Programmable Gain)
– Programmable Serial USART w ith Hardware Flow Co ntrol
– Master/Slave SPI Serial Interface
– Byte Oriented 2-wire Serial Interface
– Programmable Watchdog Timer with Separate On-chip Oscillator
– On-chip Analog Comparator
– Interrupt a nd Wake-up on Pin Change
– On-chip Temper ature Sensor
•Spec ia l Mic r oc ontroller Feature s
– Power-on Reset and Programmable Brown-out Detection
– Internal 8MHz Calibrated Oscillator
– Internal clock prescaler and On-the-fly Clock Switching (Int RC / Ext Osc)
– External and Internal Interrupt Sources
– Six Sleep Modes: Idle, ADC Noise Reduction, Power-save, Power-down, Standby, and Extended Standby
•I/O and Packages
– All I/O combine CMOS outputs and LVTTL inputs
– 26 Programmable I/O Lines
– 44-lead TQFP Package, 10x10mm
– 44-lead QFN Package, 7x7mm
•Operating Voltages
– 2.7 - 5.5V
•Operating temperature
– Industrial (-40°C to +85°C)
•Maximum Frequency
– 8MHz at 2.7V - Indust r ia l ra ng e
– 16MHz at 4.5V - Industrial range
Note: 1. See “Data Retention” on page 8 for details.
3
ATmega16U4/32U4 [DATASHEET ]
Atmel-7766JS-USB-ATmega16U4/32U4-Datasheet_04/2016
1. Pin Configurations
Figure 1-1. Pinout
2. Overview
The ATmega16U4/ATmega32U4 is a low-power CMOS 8-bit microcontroller based on the AVR enhanced RISC
architecture. By executing powerful instructions in a single clo ck cycle, th e device achieves throughputs
approaching 1 MIPS per MHz allowing the system designer to optimize power consumption versus processing
speed.
ATmega32U4
ATmega16U4
44-pin QFN/TQFP
UVcc
D-
D+
UGnd
UCap
VBus
(SS/PCINT0) PB0
(INT.6/AIN0) PE6
(PCINT1/SCLK) PB1
(PDI/PCINT2/MOSI) PB2
(
PDO/PCINT3/MISO) PB3
(
PCINT7/OC0A/OC1C/RTS) PB7
RESET
VCC
GND
XTAL2
XTAL1
(OC 0B /SC L/INT0) P D0
(SDA/INT 1) PD1
(RX D1/INT 2) P D2
(T XD 1/IN T3) PD3
(X CK 1/C T S) PD5
PE2 (HWB)
PC7 (ICP3/CLK0/OC4A)
PC6 (OC3A/OC4A)
PB6 (PCINT6/OC1B/OC4B/AD
C
PB4 (PCINT4/ADC11)
PD7 (T0/OC4D/ADC10)
PD6 (T1/OC4D/ADC9)
PD4 (ICP1/ADC8)
AVCC
GND
AREF
P F0 (ADC0)
P F1 (ADC1)
P F4 (ADC4/T CK
)
P F5 (ADC5/T M
S)
P F6 (ADC6/T D
O)
P F7 (ADC7/T D
I)
GND
VCC
INDEX CORNER
1
2
3
4
5
6
7
8
9
10
11
33
32
31
30
29
28
27
26
25
24
23
12
13
14
15
16
17
18
19
20
21
22
44
43
42
41
40
39
38
37
36
35
34
PB5 (PCINT5/OC1A/OC4B/AD
C
AVCC
GND
ATmega16U4/32U4 [DATASHEET]
Atmel-7766JS-USB-ATmega16U4/32U4-Datasheet_04/2016
4
2.1 Block Diagram
Figure 2-1. Block Diagram
The AVR core combines a rich instructio n set with 32 general purpose working registers. All the 32 registers are
directly connected to the Arithmetic Logic Unit (ALU), allowing two independe nt regist ers to be accesse d in one
single instruction executed in one clock cycle. The resulting architecture is more code efficient while achieving
throughputs up to ten times faster than conventional CISC microcontrollers.
The device provides the following features: 16/32K bytes of In-System Programmable Flash with Read-While-
Write capabilities, 512Bytes/1K bytes EEPROM, 1.25/2.5K bytes SRAM, 26 general purpose I/O lines (CMOS
outputs and LVTTL inputs), 32 genera l purpose working registers, four flexible Timer/Counters with compare
modes and PWM, one more high-speed Timer/Counter with compare modes and PLL adjustabl e source, one
USART (including CTS/RTS flo w con trol sign als ), a byte oriented 2-wire Serial Interface, a 12-channels 10-bit
ADC with optional differential input stage with programmable gain, an on-chip calibrated temperature sensor, a
programmable Watchdog Timer with Internal Oscillator, an SPI serial port, IEEE std. 1149.1 compliant JTAG
test interface, also used for accessing the On-chip De bug system and program ming and six software selectable
PROGRAM
COUNTER
STACK
POINTER
PROGRAM
FLASH
MCU CONTROL
REGISTER
GENERAL
PURPOSE
REGISTERS
INSTRUCTION
REGISTER
TIMERS/
COUNTERS
INSTRUCTION
DECODER
DATA DIR.
REG. PORTB
DATA DIR.
REG. PORTE
DATA DIR.
REG. PORTD
DATA REGISTER
PORTB
DATA REGISTER
PORTE
DATA REGISTER
PORTD
INTERRUPT
UNIT
EEPROM
SPI
STATUS
REGISTER
SRAM
USART1
Z
Y
X
ALU
PORTB DRIVERS
PORTE DRIVERS
PORTF DRIVERS
PORTD DRIVERS
PORTC DRIVERS
PB7 - PB0
PE6
PF7 - PF4
RESET
VCC
GND
XTAL1
XTAL2
CONTROL
LINES
PC7
INTERNAL
OSCILLATOR
WATCHDOG
TIMER
8-BIT DA TA BUS
USB 2.0
TIMING AND
CONTROL
OSCILLATOR
CALIB. OSC
DATA DIR.
REG. PORTC
DATA REGISTER
PORTC
ON-CHIP DEBUG
JTAG TAP
PROGRAMMING
LOGIC
BOUNDARY-
SCAN
DATA DIR.
REG. PORTF
DATA REGISTER
PORTF
POR - BOD
RESET
PD7 - PD0
TWO-WIRE SERIAL
INTERFACE
PLL
HIGH SPEED
TIMER/PWM
PE2
PC6PF1 PF0
ON-CHIP
USB PAD 3V
REGULATOR
UVcc
UCap
1uF
ANALOG
COMPARATOR
VBUS
DP
DM
ADC
AGND
AREF
AVCC
TEMPERATURE
SENSOR
5
ATmega16U4/32U4 [DATASHEET ]
Atmel-7766JS-USB-ATmega16U4/32U4-Datasheet_04/2016
power saving modes. The Idle mode stops the CPU while allowing the SRAM, Timer/Co un te rs , SPI port, and
interrupt system to continue functioning. The Power-down mode saves the register contents but freezes the
Oscillator, disabling all other chip functions until the next interrupt or Hardware Reset. The ADC Noise
Reduction mode stops the CPU and all I/O modules except ADC, to minimize switching noise during ADC
conversions. In Standby mode, the Crystal/Resonator Oscillator is running while the rest of the device is
sleeping. This allows very fast start-up combined with low power consumption.
The device is manufactured using the Atmel® high-density nonvolatile memory technology. The On-chip ISP
Flash allows the program memory to be reprogrammed in-system through an SPI seria l interface, by a
conventional nonvolatile memory programmer, or by an On-chip Boot program running on the AVR core. The
boot program can use any interface to download the application program in the application Flash memory.
Software in the Boot Flash section will continue to run while the Application Flash section is updated, providing
true Read-While-Write operation. By combining an 8-bit RISC CPU with In-System Self-Programmable Flash on
a monolithic chip, the device is a powerful microcontroller that provides a highly flexib le and cost effective
solution to many embedded control applications.
The ATmega16U4/ATmega32U4 AVR is supported with a full suite of program and system development tools
including: C compilers, macro assemblers, program debugger/simulators, in-circuit emulators, and evaluation
kits.
2.2 Pin Descriptions
2.2.1 VCC
Digital supply voltage.
2.2.2 GND
Ground.
2.2.3 Port B (PB7..PB0)
Port B is an 8-bit bi-directional I/O port with internal pull-up resistors (selected for each bit). The Port B output
buffers have symmetrical drive characteristics with both high sink and source capability. As inputs, Port B pins
that are externally pulled low will source current if the pull-up resistors are activated. The Port B pins are tri-
stated when a reset cond itio n be co m es active , ev en if the cloc k is not ru nn ing.
Port B has better driving capabilities than the other ports.
Port B also serves the fun ct ion s of va rio us spec ial fe at ur es of the devic e as listed on page 74.
2.2.4 Port C (PC7,PC6)
Port C is an 8-bit bi-directional I/O port with internal pull-up resistors (selected for each bit). The Port C output
buffers have symmetrical drive characteristics with both high sink and source capability. As inputs, Port C pins
that are externally pulled low will source current if the pull-up resistors are activated. The Port C pins are tri-
stated when a reset cond itio n be co m es active , ev en if the cloc k is not ru nn ing.
Only bits 6 and 7 are present on the product pinout.
Port C also serves the functions of special features of the device as listed on page 77.
2.2.5 Port D (PD7..PD0)
Port D is an 8-bit bi-directional I/O port with internal pull-up resistors (selected for each bit). The Port D output
buffers have symmetrical drive characteristics with both high sink and source capability. As inputs, Port D pins
that are externally pulled low will source current if the pull-up resistors are activated. The Port D pins are tri-
stated when a reset cond itio n be co m es active , ev en if the cloc k is not ru nn ing.
ATmega16U4/32U4 [DATASHEET]
Atmel-7766JS-USB-ATmega16U4/32U4-Datasheet_04/2016
6
Port D also serves the functions of various special features of the ATmega16U4/ATmega32U4 as listed on
page 78.
2.2.6 Port E (PE6,PE2)
Port E is an 8-bit bi-directional I/O port with internal pull-up resistors (selected for each bit). The Port E output
buffers have symmetrical drive characteristics with both high sink and source capability. As inputs, Port E pins
that are externally pulled low will source current if the pull-up resistors are activated. The Port E pins are tri-
stated when a reset cond itio n be co m es active , ev en if the cloc k is not ru nn ing.
Only bits 2 and 6 are present on the product pinout.
Port E also serves the fun ct ion s of va rio us spec ial fe at ur es of the ATmega16U4/ATmega32U4 as listed on
page 81.
2.2.7 Port F (PF7..PF4, PF1,PF0)
Port F serves as analog inputs to the A/D Converter.
Port F also serves as an 8-bit bi-directional I/O port, if the A/D Converter channels are not used. Port pins can
provide internal pull-up resistors (selected for each bit). The Port F output buffers have symmetrical drive
characteristics with both high sink and source capability. As inputs, Port F pins that are externally pulled low will
source current if the pull-up resistors are activated. The Port F pins are tri-stated when a reset condition
becomes active, even if the clock is not running.
Bits 2 and 3 are not pres en t on the pro duc t pin o ut .
Port F also serves the functions of the JTAG interface. If the JTAG interface is enabled, the pull-up resistors on
pins PF7(TDI), PF5(TMS), and PF4(TCK) will be activated even if a reset occurs.
2.2.8 D-
USB Full speed / Low Speed Negative Data Upstream Port. Should be connected to the USB D- connector pin
with a serial 22 resistor.
2.2.9 D+
USB Full speed / Low Speed Positive Data Upstream Port. Should be conn ected to the USB D+ connector pin
with a serial 22 resistor.
2.2.10 UGND
USB Pads Ground.
2.2.11 UVCC
USB Pads Internal Regulator Input supply voltage.
2.2.12 UCAP
USB Pads Internal Regulator Output supply voltage. Should be connected to an external capacitor (1µF).
2.2.13 VBUS
USB VBUS monitor input.
7
ATmega16U4/32U4 [DATASHEET ]
Atmel-7766JS-USB-ATmega16U4/32U4-Datasheet_04/2016
2.2.14 RESET
Reset input. A low level on this pin for longer than the minimum pulse length will generate a reset, even if the
clock is not running. The minimum pulse length is given in Table 8-2 on page 53. Shorter pulses are not
guaranteed to generate a reset.
2.2.15 XTAL1
Input to the inverting Oscillator amplifier and input to the internal clock operating circuit.
2.2.16 XTAL2
Output from the inverting Oscillator amplifier.
2.2.17 AVCC
AVCC is the supply voltage pin (input) for all the A/D Converter channels. If the ADC is not used, it should be
externally connected to VCC. If the ADC is used, it should be connected to VCC through a low-pass filter.
2.2.18 AREF
This is the analog reference pin (input) for the A/D Converter.
ATmega16U4/32U4 [DATASHEET]
Atmel-7766JS-USB-ATmega16U4/32U4-Datasheet_04/2016
8
3. About
3.1 Disclaimer
Typical values contained in this datasheet are based on simulations and characterization of othe r AVR
microcontrollers manufactured on the same process technology. Min. and Max. values will be available after the
device is characterized.
3.2 Resources
A comprehensive set of development tools, application notes and datasheets are available for download on
http://www.atmel.com/avr.
3.3 Code Examples
This documentation contains simple code examples that briefly show how to use various p arts of the device. Be
aware that not all C com piler ve nd o rs inc l ud e bit definitions in the header files and interrupt handling in C is
compiler dependent. Confirm with the C compiler documentation for more details.
These code examples assume that the part specific header file is included before compilation. For I/O registers
located in extended I/O map, "IN", "OUT", "SBIS", "SBIC", "CBI", and "SBI" instructions must be replaced with
instructions that allow access to extended I/O. Typically "LDS" and "STS" combined with "SBRS", "SBRC",
"SBR", and "CBR".
3.4 Data Retention
Reliability Qualification results show that the projected data retention failure rate is much less than 1PPM over
20 years at 85°C or 100 years at 25°C.
9
ATmega16U4/32U4 [DATASHEET SUMMARY]
Atmel-7766JS-USB-ATmega16U4/32U4-Datasheet_04/2016
4. Register Summary
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Page
(0xFF) Reserved - - - - - - - -
(0xFE) Reserved - - - - - - - -
(0xFD) Reserved - - - - - - - -
(0xFC) Reserved - - - - - - - -
(0xFB) Reserved - - - - - - - -
(0xFA) Reserved - - - - - - - -
(0xF9) Reserved - - - -
(0xF8) Reserved - - - - - - - -
(0xF7) Reserved - - - - - - - -
(0xF6) Reserved - - - - - - - -
(0xF5) Reserved - - - - - - - -
(0xF4) UEINT - EPINT6:0
(0xF3) UEBCHX - - - - -BYCT10:8
(0xF2) UEBCLX BYCT7:0
(0xF1) UEDATX DAT7:0
(0xF0) UEIENX FLERRE NAKINE - NAKOUTE RXSTPE RXOUTE STALLEDE TXINE
(0xEF) UESTA1X - - - - - CTRLDIR CURRBK1:0
(0xEE) UESTA0X CFGOK OVERFI UNDERFI - DTSEQ1:0 NBUSYBK1:0
(0xED) UECFG1X EPSIZE2:0 EPBK1:0 ALLOC -
(0xEC) UECFG0X EPTYPE1:0 - - - - - EPDIR
(0xEB) UECONX - - STALLRQ STALLRQC RSTDT - - EPEN
(0xEA) UERST -EPRST6:0
(0xE9) UENUM - - - - - EPNUM2:0
(0xE8) UEINTX FIFOCON NAKINI RWAL NAKOUTI RXSTPI RXOUTI STALLEDI TXINI
(0xE7) Reserved - - - -
(0xE6) UDMFN - - - FNCERR - - - -
(0xE5) UDFNUMH - - - - - FNUM10:8
(0xE4) UDFNUML FNUM7:0
(0xE3) UDADDR ADDEN UADD6:0
(0xE2) UDIEN - UPRSME EORSME WAKEUPE EORSTE SOFE MSOFE SUSPE
(0xE1) UDINT - UPRSMI EORSMI WAKEUPI EORSTI SOFI MSOFI SUSPI
(0xE0) UDCON - - - - RSTCPU LSM RMWKUP DETACH
(0xDF) Reserved
(0xDE) Reserved
(0xDD) Reserved
(0xDC) Reserved
(0xDB) Reserved
(0xDA) USBINT - - - - - - - VBUSTI
(0xD9) USBSTA - - - - - -IDVBUS
(0xD8) USBCON USBE -FRZCLK OTGPADE - - -VBUSTE
(0xD7) UHWCON - - - - - - - UVREGE
(0xD6) Reserved
(0xD5) Reserved
(0xD4) DT4 DT4H3 DT4H2 DT4H1 DT4H0 DT4L3 DT4L2 DT4L1 DT4L0
(0xD3) Reserved
(0xD2) OCR4D Timer/Counter4 - Output Compare Register D
(0xD1) OCR4C Timer/Counter4 - Output Compare Register C
(0xD0) OCR4B Timer/Counter4 - Output Compare Register B
(0xCF) OCR4A Timer/Counter4 - Output Compare Register A
(0xCE) UDR1 USART1 I/O Data Register
(0xCD) UBRR1H - - - - USART1 Baud Rate Register High Byte
(0xCC) UBRR1L USART1 Baud Rate Register Lo w Byte
(0xCB) UCSR1D - - - - - - CTSEN RTSEN
(0xCA) UCSR1C UMSEL11 UMSEL10 UPM11 UPM10 USBS1 UCSZ11 UCSZ10 UCPOL1
(0xC9) UCSR1B RXCIE1 TXCIE1 UDRIE1 RXEN1 TXEN1 UCSZ12 RXB81 TXB81
(0xC8) UCSR1A RXC1 TXC1 UDRE1 FE1 DOR1 PE1 U2X1 MPCM1
(0xC7) CLKSTA - - - - - - RCON EXTON
(0xC6) CLKSEL1 RCCKSEL3 RCCKSEL2 RCCKSEL1 RCCKSEL0 EXCKSEL3 EXCKSEL2 EXCKSEL1 EXCKSEL0
(0xC5) CLKSEL0 RCSUT1 RCSUT0 EXSUT1 EXSUT0 RCE EXTE -CLKS
(0xC4) TCCR4E TLOCK4 ENHC4 OC4OE5 OC4OE4 OC4OE3 OC4OE2 OC4OE1 OC4OE0
(0xC3) TCCR4D FPIE4 FPEN4 FPNC4 FPES4 FPAC4 FPF4 WGM41 WGM40
(0xC2) TCCR4C COM4A1S COM4A0S COM4B1S COM4B0S COM4D1S COM4D0S FOC4D PWM4D
(0xC1) TCCR4B PWM4X PSR4 DTPS41 DTPS40 CS43 CS42 CS41 CS40
(0xC0) TCCR4A COM4A1 COM4A0 COM4B1 COM4B0 FOC4A FOC4B PWM4A PWM4B
(0xBF) TC4H - - - - - Timer/Counter4 High Byte
10
ATmega16U4/32U4 [DATASHEET SUMMARY]
Atmel-7766JS-USB-ATmega16U4/32U4-Datasheet_04/2016
(0xBE) TCNT4 Timer/Counter4 - Counter Re gister Low Byte
(0xBD) TWAMR TWAM6 TWAM5 TWAM4 TWAM3 TWAM2 TWAM1 TWAM0 -
(0xBC) TWCR TWINT TWEA TWSTA TWSTO TWWC TWEN -TWIE
(0xBB) TWDR 2-wire Serial Interface Data Register
(0xBA) TWAR TWA6 TWA5 TWA4 TWA3 TWA2 TWA1 TWA0 TWGCE
(0xB9) TWSR TWS7 TWS6 TWS5 TWS4 TWS3 - TWPS1 TWPS0
(0xB8) TWBR 2-wire Serial Interface Bit Rate Register
(0xB7) Reserved - - - - - - - -
(0xB6) Reserved -
(0xB5) Reserved - - - - - - - -
(0xB4) Reserved - - - - - - - -
(0xB3) Reserved - - - - - - - -
(0xB2) Reserved - - - - - - - -
(0xB1) Reserved - - - - - - - -
(0xB0) Reserved - - - - - - - -
(0xAF) Reserved - - - - - - - -
(0xAE) Reserved - - - - - - - -
(0xAD) Reserved - - - - - - - -
(0xAC) Reserved - - - - - - - -
(0xAB) Reserved - - - - - - - -
(0xAA) Reserved - - - - - - - -
(0xA9) Reserved - - - - - - - -
(0xA8) Reserved - - - - - - - -
(0xA7) Reserved - - - - - - - -
(0xA6) Reserved - - - - - - - -
(0xA5) Reserved - - - - - - - -
(0xA4) Reserved - - - - - - - -
(0xA3) Reserved - - - - - - - -
(0xA2) Reserved - - - - - - - -
(0xA1) Reserved - - - - - - - -
(0xA0) Reserved - - - - - - - -
(0x9F) Reserved - - - - - - - -
(0x9E) Reserved - - - - - - - -
(0x9D) OCR3CH Timer/Counter3 - Output Compare Register C High Byte
(0x9C) OCR3CL Timer/Counter3 - Output Compare Register C Low Byte
(0x9B) OCR3BH Timer/Counter3 - Output Compare Register B High Byte
(0x9A) OCR3BL Timer/Counter3 - Output Compare Register B Low Byte
(0x99) OCR3AH Timer/ Counter3 - Output Compa re Register A High Byte
(0x98) OCR3AL Timer/Counter3 - Output Compare Register A Low Byte
(0x97) ICR3H Timer/Counter3 - Input Capture Register High Byte
(0x96) ICR3L Timer/Counter3 - Input Capture Register Low Byte
(0x95) TCNT3H Timer/Counter3 - Counter Register Hig h Byte
(0x94) TCNT3L Timer/Counter3 - Counter Register Low Byte
(0x93) Reserved - - - - - - - -
(0x92) TCCR3C FOC3A - - - - - - -
(0x91) TCCR3B ICNC3 ICES3 -WGM33 WGM32 CS32 CS31 CS30
(0x90) TCCR3A COM3A1 COM3A0 COM3B1 COM3B0 COM3C1 COM3C0 WGM31 WGM30
(0x8F) Reserved - - - - - - - -
(0x8E) Reserved - - - - - - - -
(0x8D) OCR1CH Timer/Counter1 - Output Compare Register C High Byte
(0x8C) OCR1CL Timer/Counter1 - Output Compare Register C Low Byte
(0x8B) OCR1BH Timer/Counter1 - Output Compare Register B High Byte
(0x8A) OCR1BL Timer/Counter1 - Output Compare Register B Low Byte
(0x89) OCR1AH Timer/ Counter1 - Output Compa re Register A High Byte
(0x88) OCR1AL Timer/Counter1 - Output Compare Register A Low Byte
(0x87) ICR1H Timer/Counter1 - Input Capture Register High Byte
(0x86) ICR1L Timer/Counter1 - Input Capture Register Low Byte
(0x85) TCNT1H Timer/Counter1 - Counter Register Hig h Byte
(0x84) TCNT1L Timer/Counter1 - Counter Register Low Byte
(0x83) Reserved - - - - - - - -
(0x82) TCCR1C FOC1A FOC1B FOC1C - - - - -
(0x81) TCCR1B ICNC1 ICES1 -WGM13 WGM12 CS12 CS11 CS10
(0x80) TCCR1A COM1A1 COM1A0 COM1B1 COM1B0 COM1C1 COM1C0 WGM11 WGM10
(0x7F) DIDR1 - - - - - - - AIN0D
(0x7E) DIDR0 ADC7D ADC6D ADC5D ADC4D - - ADC1D ADC0D
(0x7D) DIDR2 - - ADC13D ADC12D ADC11D ADC10D ADC9D ADC8D
(0x7C) ADMUX REFS1 REFS0 ADLAR MUX4 MUX3 MUX2 MUX1 MUX0
(0x7B) ADCSRB ADHSM ACME MUX5 - ADTS3 ADTS2 ADTS1 ADTS0
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Page
11
ATmega16U4/32U4 [DATASHEET SUMMARY]
Atmel-7766JS-USB-ATmega16U4/32U4-Datasheet_04/2016
(0x7A) ADCSRA ADEN ADSC ADATE ADIF ADIE ADPS2 ADPS1 ADPS0
(0x79) ADCH ADC Data Register High byte
(0x78) ADCL ADC Data Register Low byte
(0x77) Reserved - - - - - - - -
(0x76) Reserved - - - - - - - -
(0x75) Reserved - - - - - - - -
(0x74) Reserved - - - - - - - -
(0x73) Reserved - - - - - - - -
(0x72) TIMSK4 OCIE4D OCIE4A OCIE4B - - TOIE4 - -
(0x71) TIMSK3 - - ICIE3 -OCIE3C OCIE3B OCIE3A TOIE3
(0x70) Reserved - - - - - - - -
(0x6F) TIMSK1 - - ICIE1 -OCIE1C OCIE1B OCIE1A TOIE1
(0x6E) TIMSK0 - - - - - OCIE0B OCIE0A TOIE0
(0x6D) Reserved - - - - - - - -
(0x6C) Reserved - - - - - - - -
(0x6B) PCMSK0 PCINT7 PCINT6 PCINT5 PCINT4 PCINT3 PCINT2 PCINT1 PCINT0
(0x6A) EICRB --ISC61ISC60- - - -
(0x69) EICRA ISC31 ISC30 ISC21 ISC20 ISC11 ISC10 ISC01 ISC00
(0x68) PCICR - - - - - - -PCIE0
(0x67) RCCTRL - - - - - - - RCFREQ
(0x66) OSCCAL RC Oscillator Calibration Register
(0x65) PRR1 PRUSB - - PRTIM4 PRTIM3 -- PRUSART1
(0x64) PRR0 PRTWI -PRTIM0 -PRTIM1 PRSPI - PRADC
(0x63) Reserved - - - - - - - -
(0x62) Reserved - - - - - - - -
(0x61) CLKPR CLKPCE - - - CLKPS3 CLKPS2 CLKPS1 CLKPS0
(0x60) WDTCSR WDIF WDIE WDP3 WDCE WDE WDP2 WDP1 WDP0
0x3F (0x5F) SREG I T H S V N Z C
0x3E (0x5E) SPH SP15 SP14 SP13 SP12 SP11 SP10 SP9 SP8
0x3D (0x5D) SPL SP7 SP6 SP5 SP4 SP3 SP2 SP1 SP0
0x3C (0x5C) Reserved - - - - - - - -
0x3B (0x5B) RAMPZ - - - - - - RAMPZ1 RAMPZ0
0x3A (0x5A) Reserved - - - - - - - -
0x39 (0x59) Reserved - - - - - - - -
0x38 (0x58) Reserved - - - - - - - -
0x37 (0x57) SPMCSR SPMIE RWWSB SIGRD RWWSRE BLBSET PGWRT PGERS SPMEN
0x36 (0x56) Reserved - - - - - - - -
0x35 (0x55) MCUCR JTD - - PUD -- IVSEL IVCE
0x34 (0x54) MCUSR - - USBRF JTRF WDRF BORF EXTRF PORF
0x33 (0x53) SMCR - - - - SM2 SM1 SM0 SE
0x32 (0x52) PLLFRQ PINMUX PLLUSB PLLTM1 PLLTM0 PDIV3 PDIV2 PDIV1 PDIV0
0x31 (0x51) OCDR/
MONDR OCDR7 OCDR6 OCDR5 OCDR4 OCDR3 OCDR2 OCDR1 OCDR0
Monitor Data R egi s ter
0x30 (0x50) ACSR ACD ACBG ACO ACI ACIE ACIC ACIS1 A C IS0
0x2F (0x4F) Reserved - - - - - - - -
0x2E (0x4E) SPDR SPI Data Register
0x2D (0x4D) SPSR SPIF WCOL - - - - - SPI2X
0x2C (0x4C) SPCR SPIE SPE DORD MSTR CPOL CPHA SPR1 SPR0
0x2B (0x4B) GPIOR2 General Purpose I/O Register 2
0x2A (0x4A) GPIOR1 General Purpose I/O Register 1
0x29 (0x49) PLLCSR - - - PINDIV -- PLLE PLOCK
0x28 (0x48) OCR0B Timer/Counter0 Output Compare Register B
0x27 (0x47) OCR0A Timer/Counter0 Output Compare Register A
0x26 (0x46) TCNT0 Timer/Counter0 (8 Bit)
0x25 (0x45) TCCR0B FOC0A FOC0B - - WGM02 CS02 CS01 CS00
0x24 (0x44) TCCR0A COM0A1 COM0A0 COM0B1 COM0B0 --WGM01WGM00
0x23 (0x43) GTCCR TSM - - - - - PSRASY PSRSYNC
0x22 (0x42) EEARH - - - - EEPROM Address Register High Byte
0x21 (0x41) EEARL EEPROM Address Register Low Byte
0x20 (0x4 0) EEDR EEPROM Dat a Register
0x1F (0x3F) EECR - - EEPM1 EEPM0 EERIE EEMPE EEPE EERE
0x1E (0x3E) GPIOR0 General Purpose I/O Register 0
0x1D (0x3D) EIMSK -INT6 -- INT3 INT2 INT1 INT0
0x1C (0x3C) EIFR -INTF6 - - INTF3 INTF2 INTF1 INTF0
0x1B (0x3B) PCIFR - - - - - - -PCIF0
0x1A (0x3A) Reserved - - - - - - - -
0x19 (0x39) TIFR4 OCF4D OCF4A OCF4B --TOV4- -
0x18 (0x38) TIFR3 - - ICF3 -OCF3C OCF3B OCF3A TOV3
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Page
12
ATmega16U4/32U4 [DATASHEET SUMMARY]
Atmel-7766JS-USB-ATmega16U4/32U4-Datasheet_04/2016
Note: 1. For compatibility with future devices, reserved bits should be written to zero if accessed. Reserved I/O memory
addresses should never be written.
2. I/O registers within the address rang e $00 - $1F are directly bit-acce ssible using the SBI and CBI instructions. In these
registers, the value of single bits can be checked by using the SBIS and SBIC instructions.
3. Some of the status flags are cleared by writing a logi cal one to them. Note that the C BI and SBI instructions will operate
on all bits in the I/O register, writing a one back into any flag read as set, thus clearing the flag. The CBI and SBI instruc-
tions work with registers 0x00 to 0x1F only.
4. When using the I/O specific command s IN and OUT, the I/O addresses $00 - $3F must be used. When addressing I/O
registers as data space using LD and ST instructions, $20 must be added to these addresses. The
ATmega16U4/ATmega32U4 is a complex microcontroller with more peripheral units than can be supported within the 64
location reserved in Opcode for the IN and OUT instructions. For the Extended I/O space from $60 - $1FF in SRAM, only
the ST/STS/STD and LD/LDS/LDD instructions can be used.
0x17 (0x37) Reserved - - - - - - - -
0x16 (0x36) TIFR1 - - ICF1 -OCF1C OCF1B OCF1A TOV1
0x15 (0x35) TIFR0 - - - - - OCF0B OCF0A TOV0
0x14 (0x34) Reserved - - - - - - - -
0x13 (0x33) Reserved - - - - - - - -
0x12 (0x32) Reserved - - - - - - - -
0x11 (0x31) PORTF PORTF7 PORTF6 PORTF5 PORTF4 - - PORTF1 PORTF0
0x10 (0x30) DDRF DDF7 DDF6 DDF5 DDF4 - - DDF1 DDF0
0x0F (0x2F) PINF PINF7 PINF6 PINF5 PINF4 - - PINF1 PINF0
0x0E (0x2E) PORTE -PORTE6 - - - PORTE2 - -
0x0D (0x2D) DDRE -DDE6 - - - DDE2 - -
0x0C (0x2C) PINE -PINE6 - - - PINE2 - -
0x0B (0x2B) PORTD PORTD7 PORTD6 PORTD5 PORTD4 PORTD3 PORTD2 PORTD1 PORTD0
0x0A (0x2A) DDRD DDD7 DDD6 DDD5 DDD4 DDD3 DDD2 DDD1 DDD0
0x09 (0x29) PIND PIND7 PIND6 PIND5 PIND4 PIND3 PIND2 PIND1 PIND0
0x08 (0x28) PORTC PORTC7 PORTC6 - - - - - -
0x07 (0x27) DDRC DDC7 DDC6 - - - - - -
0x06 (0x26) PINC PINC7 PINC6 - - - - - -
0x05 (0x25) PORTB PORTB7 PORTB6 PORTB5 PORTB4 PORTB3 PORTB2 PORTB1 PORTB0
0x04 (0x24) DDRB DDB7 DDB6 DDB5 DDB4 DDB3 DDB2 DDB1 DDB0
0x03 (0x23) PINB PINB7 PINB6 PINB5 PINB4 PINB3 PINB2 PINB1 PINB0
0x02 (0x22) Reserved - - - - - - - -
0x01 (0x21) Reserved - - - - - - - -
0x00 (0x20) Reserved - - - - - - - -
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Page
13
ATmega16U4/32U4 [DATASHEET SUMMARY]
Atmel-7766JS-USB-ATmega16U4/32U4-Datasheet_04/2016
5. Instruction Set Summary
Mnemonics Operands Description Operation Flags #Clocks
ARITHMETIC AND LOGIC INSTRUCTIONS
ADD Rd, Rr Add two Registers Rd Rd + Rr Z,C,N,V,H 1
ADC Rd, Rr Add with Carry two Registers Rd Rd + Rr + C Z,C,N,V,H 1
ADIW Rdl,K Add Immediate to Word Rdh:Rdl Rdh:Rdl + K Z,C,N,V,S 2
SUB Rd, Rr Subtract two Registers Rd Rd - Rr Z,C,N,V,H 1
SUBI Rd, K Subtract Constant from Register Rd Rd - K Z,C,N,V,H 1
SBC Rd, Rr Su btract with Carry two Registers Rd Rd - Rr - C Z,C,N,V,H 1
SBCI Rd, K Subtract with Carry Constant from Reg. Rd Rd - K - C Z,C,N,V,H 1
SBIW Rdl,K Subtract Immediate from Word Rdh:Rdl Rdh:Rdl - K Z,C,N,V,S 2
AND Rd, Rr Logical A ND Registers Rd Rd Rr Z,N,V 1
ANDI Rd, K Logical AND Register an d Co nstant Rd Rd K Z,N,V 1
OR Rd, Rr Logical OR Registers Rd Rd v Rr Z,N,V 1
ORI Rd, K Logical OR Register and Constant Rd Rd v K Z,N,V 1
EOR Rd, Rr Exclusive OR Registers Rd Rd Rr Z,N,V 1
COM Rd One’s Complement Rd 0xFF Rd Z,C,N,V 1
NEG Rd Two’s Complement Rd 0x00 Rd Z,C,N,V,H 1
SBR Rd,K Set Bit(s) in Register Rd Rd v K Z,N,V 1
CBR Rd,K Clear Bit(s) in Register Rd Rd (0xFF - K) Z,N,V 1
INC Rd Increment Rd Rd + 1 Z,N,V 1
DEC Rd Decrement Rd Rd 1 Z,N,V 1
TST Rd Test for Zero or Minus Rd Rd Rd Z,N,V 1
CLR Rd Clear Register Rd Rd Rd Z,N,V 1
SER Rd Set Register Rd 0xFF None 1
MUL Rd, Rr Multiply Unsigned R1:R0 Rd x Rr Z,C 2
MULS Rd, Rr Multiply Signed R1:R0 Rd x Rr Z,C 2
MULSU Rd, Rr Multiply Signed with Unsigned R1:R0 Rd x Rr Z,C 2
FMUL Rd, Rr Fractional Multiply Unsigned R1:R0 (Rd x Rr) << 1 Z,C 2
FMULS Rd, Rr Fractional Multiply Signed R1:R0 (Rd x Rr) << 1 Z,C 2
FMULSU Rd, Rr Fractional Multiply Signed with Unsigned R1:R0 (Rd x Rr) << 1 Z,C 2
BRANCH INSTRUCTIONS
RJMP k Relative Jump PC PC + k + 1 None 2
IJMP Indirect Jump to (Z) PC Z None 2
EIJMP Extended Indirect Jump to (Z) PC (EIND:Z) None 2
JMP k Direct Jump PC kNone3
RCALL k Relative Subroutine Call PC PC + k + 1 None 4
ICALL Indirect Call to (Z) PC ZNone4
EICALL Extended Indirect Call to (Z) PC (EIND:Z) None 4
CALL k Direct Subroutine Call PC kNone5
RET Subroutine Return PC STACK None 5
RETI Interrupt Return PC STACK I 5
CPSE Rd,Rr Compare, Skip if Equal if (Rd = Rr) PC PC + 2 or 3 None 1/2/3
CP Rd,Rr Compare Rd Rr Z, N,V,C,H 1
CPC Rd,Rr Compare with Carry Rd Rr C Z, N,V,C,H 1
CPI Rd,K Compare Regi ster with Imme diate Rd K Z, N,V,C,H 1
SBRC Rr, b Skip if Bit in Register Cleared if (Rr(b)=0) PC PC + 2 or 3 None 1/2/3
SBRS Rr, b Skip if Bit in Register is Set if (Rr(b)=1) PC PC + 2 or 3 None 1/2/3
SBIC P, b Skip if Bit in I/O Register Cleared if (P (b)=0) PC PC + 2 or 3 None 1/2/3
SBIS P, b Skip if Bit in I/O Register is Set if (P(b)=1) PC PC + 2 or 3 None 1/2/3
BRBS s, k Branch if Status Flag Set if (SREG(s) = 1) then PCPC+k + 1 None 1/2
BRBC s, k Branch if Status Flag Cleared if (SREG(s) = 0) then PCPC+k + 1 None 1/2
BREQ k Branch if Eq ual if (Z = 1) then PC PC + k + 1 None 1/2
BRNE k Branch if Not Equal if (Z = 0) then PC PC + k + 1 None 1/2
BRCS k Branch if Carry Set if (C = 1) then PC PC + k + 1 Non e 1/2
BRCC k Branch if Carry Cleared if (C = 0) then PC PC + k + 1 None 1/2
BRSH k Branch if Same or Higher if (C = 0) then PC PC + k + 1 None 1/2
BRLO k Branch if Lower if (C = 1) then PC PC + k + 1 None 1/2
BRMI k Branch if Minus if (N = 1) then PC PC + k + 1 Non e 1/2
BRPL k Branch if Plus if (N = 0) then PC PC + k + 1 Non e 1/2
BRGE k Branch if Greater or Equal, Signed if (N V= 0) then PC PC + k + 1 None 1/2
BRLT k Branch if Less Than Zero, Signed if (N V= 1) then PC PC + k + 1 Non e 1/2
BRHS k Branch if Half Carry Flag Set if (H = 1) then PC PC + k + 1 Non e 1/2
BRHC k Branch if Half Carry Fla g Cleared if (H = 0) then PC PC + k + 1 None 1/2
BRTS k Branch if T Flag Set if (T = 1) then PC PC + k + 1 None 1/2
BRTC k Branch if T Flag Cleared if (T = 0) then PC PC + k + 1 None 1/2
BRVS k Branch if Overflow Flag is Set if (V = 1) then PC PC + k + 1 None 1/2
14
ATmega16U4/32U4 [DATASHEET SUMMARY]
Atmel-7766JS-USB-ATmega16U4/32U4-Datasheet_04/2016
BRVC k Branch if Overflow Flag is Cleared if (V = 0) then PC PC + k + 1 None 1/2
BRIE k Branch if Interrupt Enabled if ( I = 1) then PC PC + k + 1 None 1/2
BRID k Branch if Interrupt Disabled if ( I = 0) then PC PC + k + 1 None 1/2
BIT AND BIT-TEST INSTRUCTIONS
SBI P,b Set Bit in I/O Register I/O(P,b) 1None2
CBI P,b Clear Bit in I/O Register I/O(P,b) 0None2
LSL Rd Logical Shift Left Rd(n+1) Rd(n), Rd(0) 0 Z,C,N,V 1
LSR Rd Logical Shift Right Rd(n) Rd(n+1), Rd(7) 0 Z,C,N,V 1
ROL Rd Rotate Left Throu gh Ca r ry Rd(0)C,Rd(n+1) Rd(n),CRd(7) Z,C,N,V 1
ROR Rd Rotate Right Through Carry Rd(7)C,Rd(n) Rd(n+1), CRd(0) Z,C,N,V 1
ASR Rd Arithmetic Shift Right R d(n) Rd(n+1), n=0..6 Z,C,N,V 1
SWAP Rd Swap Nibbles Rd(3..0)Rd(7..4),Rd(7..4)Rd(3..0) None 1
BSET s Flag Set SREG(s) 1 SREG(s) 1
BCLR s Flag Clear SREG(s) 0 SREG(s) 1
BST Rr, b Bit Store from Register to T T Rr(b) T 1
BLD Rd, b Bit load from T to Register Rd(b) TNone1
SEC Set Carry C 1C1
CLC Clear Carry C 0 C 1
SEN Set Negative Flag N 1N1
CLN Clear Negative Flag N 0 N 1
SEZ Set Zero Flag Z 1Z1
CLZ Clear Zero Flag Z 0 Z 1
SEI Global Interrupt Enable I 1I1
CLI Global Interrupt Disable I 0 I 1
SES Set Signed Test Flag S 1S1
CLS Clear Signed Test Flag S 0 S 1
SEV Set Twos Complement Overflow. V 1V1
CLV Clear Twos Complement Overflow V 0 V 1
SET Set T in SREG T 1T1
CLT Clear T in SREG T 0 T 1
SEH Set Half Carry Flag in SRE G H 1H1
CLH Clear Half Carry Flag in SREG H 0 H 1
DATA TRANSFER INSTRUCTIONS
MOV Rd, Rr Move Between Registers Rd Rr None 1
MOVW Rd, Rr Copy Register Word Rd+1:Rd Rr+1:R r None 1
LDI Rd, K Load Immediate Rd KNone1
LD Rd, X Load Indirect Rd (X) None 2
LD Rd, X+ Load Indirect and Post-Inc. Rd (X), X X + 1 None 2
LD Rd, - X Load Indirect an d Pre-Dec. X X - 1, Rd (X) None 2
LD Rd, Y Load Indirect Rd (Y) None 2
LD Rd, Y+ Load Indirect and Post-Inc. Rd (Y), Y Y + 1 None 2
LD Rd, - Y Load Indirect an d Pre-Dec. Y Y - 1, Rd (Y) None 2
LDD Rd,Y+q Load Indirect with Displacement Rd (Y + q) None 2
LD Rd, Z Load Indirect Rd (Z) None 2
LD Rd, Z+ Load Indirect and Post-Inc. Rd (Z), Z Z+1 None 2
LD Rd, -Z Load Indirect and Pre-Dec. Z Z - 1, Rd (Z) None 2
LDD Rd, Z+q Load Indirect with Displacement Rd (Z + q) None 2
LDS Rd, k Load Direct from SRAM Rd (k) None 2
ST X, Rr Store Indirect (X) Rr None 2
ST X+, Rr Store Indirect and Post-Inc. (X) Rr, X X + 1 None 2
ST - X, Rr Store Indirect and Pre-Dec. X X - 1, (X) Rr None 2
ST Y, Rr Store Indirect (Y) Rr None 2
ST Y+, Rr Store Indirect and Post-Inc. (Y) Rr, Y Y + 1 None 2
ST - Y, Rr Store Indirect and Pre-Dec. Y Y - 1, (Y) Rr None 2
STD Y+q,Rr Store Indirect with Displacement (Y + q) Rr None 2
ST Z, Rr Store Indirect (Z) Rr None 2
ST Z+, Rr Store Indirect and Post-Inc. (Z) Rr, Z Z + 1 None 2
ST -Z, Rr Store Indirect and Pre-Dec. Z Z - 1, (Z) Rr None 2
STD Z+q,Rr Store Indirect with Displacement (Z + q) Rr None 2
STS k, Rr Store Direct to SRAM (k) Rr None 2
LPM Load P r ogram Memory R0 (Z) None 3
LPM Rd, Z Load Program Memory Rd (Z) None 3
LPM Rd, Z+ Load Program Memory and Post-Inc Rd (Z), Z Z+1 None 3
ELPM Extend ed Load Pr ogram Memory R0 (RAMPZ:Z) None 3
ELPM Rd, Z Extended Load Program Memory Rd (Z) None 3
ELPM Rd, Z+ Extended Load Program Memory Rd (RAMPZ:Z), RAMPZ:Z RAMPZ:Z+1 None 3
SPM Store Program Memory (Z) R1:R0 None -
IN Rd, P In Port Rd PNone1
Mnemonics Operands Description Operation Flags #Clocks
15
ATmega16U4/32U4 [DATASHEET SUMMARY]
Atmel-7766JS-USB-ATmega16U4/32U4-Datasheet_04/2016
OUT P, Rr Out Port P Rr None 1
PUSH Rr Push Register on Stack STACK Rr None 2
POP Rd Pop Register from Stack Rd STACK None 2
MCU CONTROL INSTRUCTIONS
NOP No Operation None 1
SLEEP Sleep (see specific description for Sleep function) None 1
WDR Watchdog Reset (see specific description for WDR/timer) None 1
BREAK Break For On-chip Debug Only None N/A
Mnemonics Operands Description Operation Flags #Clocks
16
ATmega16U4/32U4 [DATASHEET]
Atmel-7766JS-USB-ATmega16U4/32U4-Datasheet_04/2016
6. Ordering Information
6.1 ATmega16U4
Notes: 1. For more information on running the USB from internal RC oscillato r consult application note AVR291: 8MHz Internal Oscillator Calibration for USB Low
Speed on Atmel ATmega32U4RC.
2. USB operation from internal RC oscillator is only guaranteed for 0°C to 40°C.
3. These parts are shipped with no USB bootloader pre-progr ammed.
Speed [MHz] Power Supply Ordering Code Default Oscillat or Package Operation Range
16 2.7 - 5.5V
ATmega16U4-AU External XTAL 44ML
Industrial (-40° to +85°C)
ATmega16U4RC-AU Internal Calib. RC
ATmega16U4-MU
(1)(2)(3) External XTAL
44PW
ATmega16U4RC-MU
(1)(2)(3) Internal Calib. RC
Package Type
44ML ML, 44 - Lead, 10 x 10mm Body Size, 1.0mm Body Thickness
0.8mm Lead Pitch, Thin Profile Plastic Quad Flat Package (TQFP)
44PW PW, 44 - Lead 7.0 x 7.0mm Body, 0.50mm Pitch
Quad Flat No Lead Package (QFN)
17
ATmega16U4/32U4 [DATASHEET]
Atmel-7766JS-USB-ATmega16U4/32U4-Datasheet_04/2016
6.2 ATmega32U4
Notes: 1. For more information on running the USB from internal RC oscillato r consult application note AVR291: 8MHz Internal Oscillator Calibration for USB Low
Speed on Atmel ATmega32U4RC.
2. USB operation from internal RC oscillator is only guaranteed for 0°C to 40°C.
3. These parts are shipped with no USB bootloader pre-progr ammed.
Speed [MHz] Power Supply Ordering Code Default Oscillat or Package Operation Range
16 2.7 - 5.5V
ATmega32U4-AU External XTAL 44ML
Industrial (-40° to +85°C)
ATmega32U4RC-AU Internal Calib. RC
ATmega32U4-MU(1)(2)(3) External XTAL
44PW
ATmega32U4RC-MU(1)
(2) (3) Internal Calib. RC
Package Type
44ML ML, 44 - Lead, 10 x 10mm Body Size, 1.0mm Body Thickness
0.8mm Lead Pitch, Thin Profile Plastic Qu ad Flat Package (TQFP)
44PW PW, 44 - Lead 7.0 x 7.0mm Body, 0.50mm Pitch
Quad Flat No Lead Package (QFN)
18
ATmega16U4/32U4 [DATASHEET]
Atmel-7766JS-USB-ATmega16U4/32U4-Datasheet_04/2016
7. Packaging Information
7.1 TQFP44
0.37
0.60
0.17
02/06/2014
J
19
ATmega16U4/32U4 [DATASHEET]
Atmel-7766JS-USB-ATmega16U4/32U4-Datasheet_04/2016
7.2 QFN44
20
ATmega16U4/32U4 [DATASHEET]
Atmel-7766JS-USB-ATmega16U4/32U4-Datasheet_04/2016
21
ATmega16U4/32U4 [DATASHEET]
Atmel-7766JS-USB-ATmega16U4/32U4-Datasheet_04/2016
8. Errata
The revision letter in this section refers to the revision of the ATmega16U4/ATmega32U4 device.
8.1 ATmega16U4/ATmega32U4 Rev E
•Spike on TW I pin s when TW I is enabled
•High current consumpt ion in sleep mode
•MSB of OCR4A/B/D is write only in 11-bits enhanced PWM mod e
1. Spike on TWI pins when TWI is enabled
100 ns negative spike occurs on SDA and SCL pins when TWI is enabled.
Problem Fix/work aro u nd
Enable ATmega16U4/ATmega32U4 TWI before the other nodes of the TWI network.
2. High current consumption in sleep mode
If a pending interrupt cannot wake the part up from the selected mode, the current consumption will
increase during sleep when executing the SLEEP instruction directly after a SEI instruction.
Problem Fix/work aro u nd
Before entering sleep, interrupts not used to wake up the part from the sleep mode should be disabled.
3. MSB of OCR4A/B/D is write only in 11-bits enhanced PWM mode
In the 11-bits enhanced PWM mode the MSB of OCR4A/B/D is write only. A read of OCR4A/B/D will
always return zero in the MSB position.
Problem Fix/work aro u nd
None.
8.2 ATmega16U4/ATmega32U4 Rev D
•Spike on TW I pin s when TW I is enabled
•High current consumpt ion in sleep mode
•Timer 4 11-bits enhanced PWM mode
1. Spike on TWI pins when TWI is enabled
100 ns negative spike occurs on SDA and SCL pins when TWI is enabled.
Problem Fix/work aro u nd
Enable ATmega16U4/ATmega32U4 TWI before the other nodes of the TWI network.
2. High current consumption in sleep mode
If a pending interrupt cannot wake the part up from the selected mode, the current consumption will
increase during sleep when executing the SLEEP instruction directly after a SEI instruction.
Problem Fix/work aro u nd
Before entering sleep, interrupts not used to wake up the part from the sleep mode should be disabled.
3. Timer 4 11-bits enhanced PWM mode
Timer 4 11-bits enhanced mode is not functional.
Problem Fix/work aro u nd
None.
22
ATmega16U4/32U4 [DATASHEET]
Atmel-7766JS-USB-ATmega16U4/32U4-Datasheet_04/2016
8.3 ATmega16U4/ATmega32U4 Rev C
Not sampled
8.4 ATmega16U4/ATmega32U4 Rev B
•Spike on TW I pin s when TW I is enabled
•High current consumpt ion in sleep mode
•Incorrect execution of VBUSTI interrupt
•Timer 4 11-bits enhanced PWM mode
1. Spike on TWI pins when TWI is enabled
100 ns negative spike occurs on SDA and SCL pins when TWI is enabled.
Problem Fix/work aro u nd
Enable ATmega16U4/ATmega32U4 TWI before the other nodes of the TWI network.
2. High current consumption in sleep mode
If a pending interrupt cannot wake the part up from the selected mode, the current consumption will
increase during sleep when executing the SLEEP instruction directly after a SEI instruction.
Problem Fix/work aro u nd
Before entering sleep, interrupts not used to wake up the part from the sleep mode should be disabled.
3. Incorrect execution of VBUSTI interrupt
The CPU may incorrectly execute the interrupt vector related to the VBUSTI interrupt flag.
Problem fix/work around
Do not enable this interrupt. Firmware must process this USB event by polling VBUSTI.
4. Timer 4 11-bits enhanced PWM mode
Timer 4 11-bits enhanced mode is not functional.
Problem Fix/work aro u nd
None.
8.5 ATmega16U4/ATmega32U4 Rev A
•Spike on TW I pin s when TW I is enabled
•High current consumpt ion in sleep mode
•Increased power consumption in power-down mode
•Internal RC oscillator start up may fail
•Internal RC oscillator calibration
•Incorrect execution of VBUSTI interrupt
•Timer 4 enhanced mode issue
1. Spike on TWI pins when TWI is enabled
100 ns negative spike occurs on SDA and SCL pins when TWI is enabled.
Problem Fix/work aro u nd
Enable ATmega16U4/ATmega32U4 TWI before the other nodes of the TWI network.
2. High current consumption in sleep mode
23
ATmega16U4/32U4 [DATASHEET]
Atmel-7766JS-USB-ATmega16U4/32U4-Datasheet_04/2016
If a pending interrupt cannot wake the part up from the selected mode, the current consumption will
increase during sleep when executing the SLEEP instruction directly after a SEI instruction.
Problem Fix/work aro u nd
Before entering sleep, interrupts not used to wake up the part from the sleep mode should be disabled.
3. Increased power consumption in power-down mode
The typical power consumption is increased by about 30 µA in power-down mode.
Problem Fix/work aro u nd
None.
4. Internal RC os c ill at or st art up may fail
When the part is configured to start on internal RC oscillator, the oscillator may not start properly after
power-on.
Problem Fix/work aro u nd
Do not configure the part to start on internal RC oscillator.
5. Internal RC os c ill at or calib ra tio n
8 MHz frequency can be impossible to reach with internal RC even when using maximal OSCAL value.
Problem Fix/work aro u nd
None.
6. Incorrect execution of VBUSTI interrupt
The CPU may incorrectly execute the interrupt vector related to the VBUSTI interrupt flag.
Problem fix/work around
Do not enable this interrupt. Firmware must process this USB event by polling VBUSTI.
7. Timer 4 11-bits enhanced PWM mode
Timer 4 11-bits enhanced mode is not functional.
Problem Fix/work aro u nd
None.
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ATmega16U4/32U4 [DATASHEET]
Atmel-7766JS-USB-ATmega16U4/32U4-Datasheet_04/2016
9. Datasheet Revision History for ATmega16U4/ATmega32U4
Note that the referring page numbers in this section are referred to this d ocument . The refer ring revision in this
section are referring to the document revision.
9.1 Rev. 7766J – 04/2016
9.2 Rev. 7766I – 07/2015
9.3 Rev. 7766H – 06/2014
1. “Memory Programming” on pag e 353: Updated number of words in a page and number of
pages in the Flash and EEPROM for ATmega16U4 and ATmega32U4. Refer to Table 28-11
and Table 28-12 on page 359.
1. Applied Atmel brands throughout the contents and reorganized the contents.
2. Updated “Power Management and Sleep Modes” on page 43. Part of contents was missing.
1. The first section in “Phase and Frequency Correct PWM Mode” on page 154 has been
corrected.
2. Several corrections are made according to the new template.
3. Trademarks are added to the last page.
4Removed preli m i nary on the front pa ge
5Updated with new datasheet template from 05-2014
6. Updated description of parts pre-programed with a default USB bootlo ader in Features on
page 2.
7. Added three footnotes for the RC part numbers in Section 6., “Ordering Information” on page
16.
8. Removed footnote on Frequency range inTable 6-3 on page 30 and Tabl e 6-7 on page 32.
9. Updated values and removed footnote in Table 8-3 on page 55.
10. Removed column VCC=1.5 - 5.5V in Table 29- 2 on page 385.
11. Changed footnote for Table 29-2 on page 385.
12. Added max value for Rise/Fall time in Table 29-4 on page 387.
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9.4 Rev. 7766G – 02/2014
9.5 Rev. 7766F – 11/10
9.6 Rev. 7766E – 04/10
1. Updated the “Descri ption” on page 177 of the “Output Compare Modulator (OCM1C0A)” .
Sp ecified when the logical AND and the logical OR will be performed based on the PORTB7.
2. Updated “USART Control and Status Register n D– UCSRnD” on page 213. “Bits 7:2 -
Reserved” are Read only.
3. Updated “Crystal-less Operation” on page 259. The temperature range changed to “within the
0C and +40C.
4. MUX bit in “ADC Control and Status Register B – ADCSRB” on page 294 changed to R/W .
5. Updated Table 24-6 on page 318. Trigger Source: Timer/Counter0 Compare Match updated
to T imer/Counter0 Compare Match A.
6. Updated “DC Characteristics” on page 383. Added Active 16MHz, VCC = 5V, max. 27mA, in
“Icc / Power supply current”.
7. Updated “Register Summary” on page 9. Added UCSRnD at the address CBh.
8. Replaced the “TQFP44” on page 18 and “QFN44” on page 19 by updated package drawings.
9. Updated the last page according to Atmel new Brand Style Guide (new logo).
1. Replaced the “QFN44” on page 19 by an updated drawing.
2. Updated “ADC Control and Status Register B – ADCSRB” on page 294. Defined the
ADCSRB register as in “ADC Control and Status Register B – ADCSRB” on page 317 .
3. Updated the last page according to Atmel new Brand Style Guide.
1. Updated “Fea tures” on page 1.
2. Updated “Fea tures” on page 256.
3. Updated Figure 21-9 on page 261.
4. Updated Secti on 21.8 on page 263.
5. Updated “Fea tures” on page 297.
6. Updated “Boundary-scan Order” on page 332.
7. Updated “Program And Data Memory Lock Bits” on page 353.
8. Updated Table 28-5 on page 355.
9. Updated “Electrical Characteristics” on page 383 .
10. Updated Figure 29-2 on page 386.
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ATmega16U4/32U4 [DATASHEET]
Atmel-7766JS-USB-ATmega16U4/32U4-Datasheet_04/2016
9.7 Rev. 7766D – 01/09
9.8 Rev. 7766C – 11/08
9.9 Rev. 7766B – 11/08
9.10 Rev. 7766A – 07/08
11. Added “Typical Characteristics” on page 392.
12. Updated “Orderi ng Information” on page 16.
13. Updated “Errata” on page 21.
1. Updated Memory section in “Features” on page 1.
2. Added section “Resources” on page 8.
3. Added section “Data Retention” on page 8.
4. Updated “Orderi ng Information” on page 16.
1. Updated Memory section in “Features” on page 1.
1. Added ATmega16U4 device.
2. Created errata section and added ATmega16U4.
3. Updated High Speed Timer, asy nch r onou s de scr ip tion Section 15. on page 139
1. Initial revision
X
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