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

306
7679H–CAN–08/08
AT90CAN32/64/128
Figure 23-4. General Port Pin Schematic Diagram
23.6.2 Boundary-scan and the Two-wire Interface
The two Two-wire Interface pins SCL and SDA have one additional control signal in the scan-
chain; Two-wire Interface Enable – TWIEN. As shown in Figure 23-5, the TWIEN signal enables
a tri-state buffer with slew-rate control in parallel with the ordinary digital port pins. A general
scan cell as shown in Figure 23-9 is attached to the TWIEN signal.
Notes: 1. A separate scan chain for the 50 ns spike filter on the input is not provided. The ordinary scan
support for digital port pins suffice for connectivity tests. The only reason for having TWIEN in
the scan path, is to be able to disconnect the slew-rate control buffer when doing boundary-
scan.
2. Make sure the OC and TWIEN signals are not asserted simultaneously, as this will lead to
drive contention.
CLK
RPx
RRx
WPx
RDx
WDx
PUD
SYNCHRONIZER
WDx: WRITE DDRx
WPx: WRITE PORTx
RRx: READ PORTx REGISTER
RPx: READ PORTx PIN
PUD: PULLUP DISABLE
CLK : I/O CLOCK
RDx: READ DDRx
D
L
Q
Q
RESET
RESET
Q
Q
D
Q
Q
D
CLR
PORTxn
Q
Q
D
CLR
DDxn
PINxn
DATA BUS
SLEEP
SLEEP: SLEEP CONTROL
Pxn
I/O
I/O
See Boundary-scan
Description for Details!
PUExn
OCxn
ODxn
IDxn
PUExn: PULLUP ENABLE for pin Pxn
OCxn: OUTPUT CONTROL for pin Pxn
ODxn: OUTPUT DATA to pin Pxn
IDxn: INPUT DATA from pin Pxn