CAN microcontrollers - Atmel Corporation

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Frequently Asked Questions (FAQ) on

T89C51CC01 CAN microcontrollers

Q1: What is the T89C51CC01?

A1: First member of the Atmel Wireless & Microcontrollers CANary family, the microcontrollers dedicated to

CAN applications. Besides the CAN Controller the T89C51CC01 features:

- 32 Kbytes User Flash Memory

- 2 Kbytes Boot Flash Memory

- 2 Kbytes EEPROM

- 1.2 Kbytes RAM

- ADC 10-bit (8 channels)

- PCA (5 channels), Timer 0, 1 & 2

- Enhanced UART

Q2: What does CAN mean?

A2: CAN stand for “Controller Area Network”. It presents a protocol for serial communication bus and is

defined in the ISO 11898. CAN was developed by BOSCH in the 80’s for automotive applications. Today CAN

has gained widespread use also in Industrial Applications.

Q3: What differentiate the Atmel CAN Controller from other manufacturer CAN offering?

A3: The differentiation is summarized by the words ‘Flexibility’ and ‘Security’.

- Ultimate System Flexibility is achieved by programming the 32 Kbytes User Flash and the 2 Kbytes EEPROM

via the CAN bus (ISP) in embedded applications.

- The physical separation of User and Boot Flash Memory assures that the Boot Loader located in the Boot

Memory can’t be affected by any manipulation in an embedded application. This is achieved by a different

operating mode of the Boot Flash Memory vs. the User Flash Memory: The Boot Flash Memory can be

programmed or altered only in parallel mode by a programmer. This means the Boot program is well-protected in

embedded applications.

- All parameters and features of the CAN Controller can be changed on the fly. In other words: After completion

of a job the concerned ‘channel’ can be completely re-configured for the next job.

Q4: What is an ISP?

A4: ISP stands for In-System-Programming, meaning that an embedded Microcontroller can be programmed

via a serial link. ISP of the CANary is not only possible via CAN bus but also via UART or any other custom

tailored serial interface using e.g. one PCA channel.

Q5: What is a Boot Loader?

A5: The Boot Loader is a software program which assures the transfer of code bytes located e.g. in the data

bytes of the frames on the CAN bus via CAN Controller to the right addresses of the User Flash Memory. The

Boot Loaders for CAN, UART and further API are delivered by Atmel Wireless & Microcontrollers and are by

default located in the Boot Flash Memory.

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Q6: What is happen when the Customer needs his own special Boot Loader?

A6: Of course, the customer can write his own boot loader. Finally there are two possibilities for its location.

Either the customer boot loader will replace the default Boot Loader in the Boot Flash Memory or the default Boot

Loader is used to place the customer boot loader also in the User Flash Memory.

Q7: What is API?

A7: API stands for “Application Programming Interfaces”. These software routines also called “driver” handle

e.g. the CAN Controller management, read and write access to all on-chip non-volatile memories, etc.

All these APIs are part of the Atmel Wireless & Microcontrollers CANary offering.

Q8: Is the ISP also applicable to the EEPROM?

A8: Of course, also the EEPROM can be programmed or altered via CAN bus. A very important point, because

the EEPROM is often used to store application parameters. These will change in embedded applications during

the lifetime of a product.

Q9: What else is special on our non-volatile Memories?

A9: The Flash memories and EEPROM are programmable by byte or by page (including 128 Bytes) or by a

number of bytes in a page. No need for a special erase cycle before any programming. Our Non-volatile

memories are self-erasure.

Q10: What means ‘channel’?

A10: T89C51CC02 has 15 channels. Each channel can treat one message object, consisting of 20 bytes each,

including an 8 bytes cyclic data shift register. Each unit works independently following the configuration chosen

as:

- Receiver

- Transmitter

- Receiver Buffer

- Either on the 2.0A or 2.0B CAN protocol.

Q11: What is the use of the other 12 bytes of one channel?

A11:

- 4 bytes for programming the identifier (ID Tag register)

- 4 bytes for masking the identifier bits (ID Mask register)

- 2 bytes for Status & Control

- 2 bytes for the Time Stamp Register

Q12: I understand Receiver, Transmitter, but what does Receiver Buffer mean?

A12: After ‘flexibility’ here a further important feature of our CAN Controller: In Receiver Buffer mode 1 to 15

channels can participate, in a non-consecutive sequence, to built-up a 120 byte wide data receiver buffer. In this

case all concerned ID Tag registers are programmed on the same identifier.

The lowest channel number will be served first.

This feature, in older days also called “Basic CAN Feature” will help that no important message on the CAN bus

is missed or to ease the transfer of data strings longer than 8 bytes. (One CAN frame is limited to 8 data bytes).

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Q13: These flexible channels, how is their control managed?

A13: Based on 33 SFRs (Special Function Registers), also called mailbox, the 180 registers and the 120 data

bytes of the CAN Controller are managed by a very efficient pagination system. See special application note

which shows the efficiency of our system vs. competitors.

Q14: What else is special on our CAN Controller?

A14: Just to mention two nice features that aren’t common to our competitors:

- Auto Reply Mode is starting transmission without software intervention after reception of a corresponding

Remote Frame. This allows fast reaction on urgent requests!

- Autobaud & Listening mode give the tools for a hot-plug of Bus nodes to running networks with unknown bit-

rate.

Q15: What are the available speeds?

A15: There are several speed definitions:

- First the maximal Baud rate on the CAN Bus managed by the CANary CAN Controller is 1Mbits/sec at minimal

8 MHz Crystal Frequency in X2 mode (1Mbit/sec is also the maximal rate in the CAN protocol).

- An independent Baud Rate generator will divide to lower speeds if requested.

- Processor speeds:

. 33 MHz @ 5V

. 20 MHz @ 5V X2 mode

. 24 MHz @ 3V *

. 16 MHz @ 3V X2 mode *

* Check for availability

Q16: What are the temperature ranges available?

A16: The T89C51CC01 will be commercialized first in the Industrial Range (-40°C to 85°C) and expanding to

wider ranges after introduction of the product. By the way: The Industrial Range will not exclude special body

automotive applications accepted by several automotive customers.

Q17: Flash is fine, but very high volume in automotive applications requests still a ROM!

A17: For several reasons the trend is going to flash solutions, also for high volume. But it is right that

applications, very cost sensitive, in very high volume, require a ROM. We got this point and we have started such

project. The ROM version will be available Q2/2001.

Q18: What packages are available?

A18: Following customer requests the following packages are used:

PLCC44, TQFP44 (1.4mm height), CA-BGA64

Q19: Which tools are available to support the new CANary family?

A19: The KEIL simulator is available now.

The first T89C51CC01 emulator from HITEX is available in November 2000.

Nohau and Metalink emulators will be available shortly behind.

The programmers are available also in November 2000.

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Q20: Does the T89C51CC01 have security lock bits?

A20: Yes.

They are four lock bits levels:

1- No program lock features enabled.

2- MOVC instruction executed from external program memory are disabled from fetching code bytes from internal

memory, EA is sampled and latched on reset, and further programming of the Flash memory is disabled.

3- Same as 2, also verify is disabled

4- Same as 3, also external execution is disabled.

Q21: What Process is used for Canary family?

A21: The state-of–the-art 0.35µm/3Volt EEPROM/Flash technology is used for the Canary family. This means

that on-chip Regulators are used to have a VCC = 5V device.

Q22: What signify the name CANary?

A22: In the beginning of the project “Canary” was the company internal project name of the T89C51CC01.

Today it is the family name for all CAN related microcontrollers from Atmel Wireless & Microcontrollers.

Q23: What are the future derivatives of the CANary Family?

A23: The design is working on a low-pin/low- cost version of the T89C51CC01, called T89C51CC02 with 16

Kbytes Flash.. It will come in 24/28 pin packages and will be full compatible to its precedor. Market introduction

will be one quarter behind the T89C51CC01. A ROM version of both will be available in Q2/2000.

Further a jump to higer CPU power is in the pipe, using an ARM core and a multi CAN module Of cource based

on the famous Atmel Flash Technology including ISP. Introduction date is Q3/2001.

Q24: Why CAN for industrial Applications?

A24: Like you know CAN is the incontestable Leader in automotive and industrial applications with more then 200

Million nodes installed today, including 10% industrial nodes. Thanks to its matured protocol that is implemented

in hardware it is also the safest bus on the market. Here the strong points of CAN:

- Simple transmission medium

- Excellent Error handling

- Fine Fault Confinement

- Best Performance/Price ratio

For more details refer to the Atmel Wireless & Microcontrollers CAN Tutorial.

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Q25: What about the 10bit ADC?

A25: Like you know the circuit works internally at 3 Volt, including the ADC. For noise reduction the ADC has its

own regulator. Beside this, the Voltage range for the multiplexed ADC inputs is 3 Volt. (Also in 5 Volt

applications).

Q26: What are the available Voltage Ranges?

A26: The T89C51CC01 will be characterized first at 5Volt. Depends on market evolution an optimized 3Volt

device will be available quickly (metal mask modification).

Remember that CANary works internally at 3Volt. This means also the 5Volt device will work at 3Volt without any

modification, but still with connected regulators. This will be OK for 3 Volt applications which aren’t sensitive on

Power-Down consumption.

Q27: What about prices?

A27: Please refer to your next Atmel Wireless & Microcontrollers Sales Office.

Q28: What about product availability?

A28: First sampling of T89C51CC01 to selected alpha customers was made in September 2000. General

sampling will be in November 2000. The production start is planned for Q1/2001.