Datasheet
Table Of Contents
- 1. Description
- 2. About Code Examples
- 3. AVR CPU Core
- 4. Memories
- 5. System Clock
- 6. Power Management and Sleep Modes
- 7. System Control and Reset
- 8. Interrupts
- 9. I/O-Ports
- 10. External Interrupts
- 11. Timer/Counter3/1/0 Prescalers
- 12. 8-bit Timer/Counter0 with PWM
- 13. 16-bit Timer/Counter (Timer/Counter1 and Timer/Counter3)
- 14. 8-bit Timer/Counter2 with PWM and Asynchronous Operation
- 14.1 Features
- 14.2 Overview
- 14.3 Timer/Counter Clock Sources
- 14.4 Counter Unit
- 14.5 Output Compare Unit
- 14.6 Compare Match Output Unit
- 14.7 Modes of Operation
- 14.8 Timer/Counter Timing Diagrams
- 14.9 8-bit Timer/Counter Register Description
- 14.10 Asynchronous operation of the Timer/Counter2
- 14.11 Timer/Counter2 Prescaler
- 15. Output Compare Modulator - OCM
- 16. Serial Peripheral Interface - SPI
- 17. USART (USART0 and USART1)
- 17.1 Features
- 17.2 Overview
- 17.3 Dual USART
- 17.4 Clock Generation
- 17.5 Serial Frame
- 17.6 USART Initialization
- 17.7 Data Transmission - USART Transmitter
- 17.8 Data Reception - USART Receiver
- 17.9 Asynchronous Data Reception
- 17.10 Multi-processor Communication Mode
- 17.11 USART Register Description
- 17.12 Examples of Baud Rate Setting
- 18. Two-wire Serial Interface
- 19. Controller Area Network - CAN
- 20. Analog Comparator
- 21. Analog to Digital Converter - ADC
- 22. JTAG Interface and On-chip Debug System
- 23. Boundary-scan IEEE 1149.1 (JTAG)
- 24. Boot Loader Support - Read-While-Write Self-Programming
- 25. Memory Programming
- 26. Electrical Characteristics (1)
- 26.1 Absolute Maximum Ratings*
- 26.2 DC Characteristics
- 26.3 External Clock Drive Characteristics
- 26.4 Maximum Speed vs. VCC
- 26.5 Two-wire Serial Interface Characteristics
- 26.6 SPI Timing Characteristics
- 26.7 CAN Physical Layer Characteristics
- 26.8 ADC Characteristics
- 26.9 External Data Memory Characteristics
- 26.10 Parallel Programming Characteristics
- 27. Decoupling Capacitors
- 28. AT90CAN32/64/128 Typical Characteristics
- 28.1 Active Supply Current
- 28.2 Idle Supply Current
- 28.3 Power-down Supply Current
- 28.4 Power-save Supply Current
- 28.5 Standby Supply Current
- 28.6 Pin Pull-up
- 28.7 Pin Driver Strength
- 28.8 Pin Thresholds and Hysteresis
- 28.9 BOD Thresholds and Analog Comparator Offset
- 28.10 Internal Oscillator Speed
- 28.11 Current Consumption of Peripheral Units
- 28.12 Current Consumption in Reset and Reset Pulse Width
- 29. Register Summary
- 30. Instruction Set Summary
- 31. Ordering Information
- 32. Packaging Information
- 33. Errata
- 34. Datasheet Revision History for AT90CAN32/64/128
- 34.1 Changes from 7679G - 03/08 to 7679H - 08/08
- 34.2 Changes from 7679F - 11/07 to 7679G - 03/08
- 34.3 Changes from 7679E - 07/07 to 7679F - 11/07
- 34.4 Changes from 7679D - 02/07 to 7679E - 07/07
- 34.5 Changes from 7679C - 01/07 to 7679D - 02/07
- 34.6 Changes from 7679B - 11/06 to 7679C - 01/07
- 34.7 Changes from 7679A - 10/06 to 7679B - 11/06
- 34.8 Document Creation
418
7679H–CAN–08/08
AT90CAN32/64/128
minimum delay will be 39-bit time in CAN2.0B. See CAN2.0A CAN2.0B frame timings
below.
Workaround implementation
The workaround is to have the last MOb (MOb14) as "spy" enabled all the time; it is the MOb
of lowest priority. If a MOb other than MOb14 is programmed in receive mode and its accep-
tance filter matches with the incoming message ID, this MOb will take the message. MOb14
will only take messages than no other MObs will have accepted. MOb14 will need to be re-
enabled fast enough to manage back to back frames. The deadline to do this is the begin-
ning of DLC slot of incoming frames as explained above.
Minimum code to insert in CAN interrupt routine:
__interrupt void can_int_handler(void)
{
if ((CANSIT1 & 0x40) == 0x40 ) /* MOb14 interrupt (SIT14=1) */
{
CANPAGE = (0x0E << 4); /* select MOb14 */
CANSTMOB = 0x00; /* reset MOb14 status */
CANCDMOB = 0x88; /* reception enable */
}
........
........
}
5. Asynchronous Timer-2 wakes up without interrupt
The asynchronous timer can wake from sleep without giving interrupt. The error only occurs
if the interrupt flag(s) is cleared by software less than 4 cycles before going to sleep and this
clear is done exactly when it is supposed to be set (compare match or overflow). Only the
interrupts flags are affected by the clear, not the signal witch is used to wake up the part.
Problem fix / workaround
No known workaround, try to lock the code to avoid such a timing.
CAN 2.0A
19-bit time minimum
T
1
(RXOK)
T
2
Arbitration
Field
Control
Field
End of Frame
CRC
Field
ACK
Field
Inter-
mission
11-bit identifier
ID10..0
CRC
del.
ACK
del.
15-bit CRC
SOF
SOF
RTR
IDE r0ACK
7 bits
4-bit DLC
DLC4..0
3 bits
CAN 2.0B
39-bit time minimum
T
1
(RXOK)
T
2
End of Frame
CRC
Field
ACK
Field
Inter-
mission
Arbitration
Field
Control
Field
CRC
del.
ACK
del.
15-bit CRC
SOF
SOF
ACK
7 bits 3 bits
11-bit base identifier
IDT28..18
18-bit identifier extension
ID17..0
4-bit DLC
DLC4..0
SRR
IDE r0RTR r1