
ii
AT90CAN128
4250E–CAN–12/04
Power-down Mode.............................................................................................. 44
Power-save Mode............................................................................................... 44
Standby Mode..................................................................................................... 45
Minimizing Power Consumption ......................................................................... 45
System Control and Reset................................................................. 47
Internal Voltage Reference................................................................................. 52
Watchdog Timer ..................................................................................................53
Timed Sequences for Changing the Configuration of the Watchdog Timer ....... 55
Interrupts............................................................................................. 56
Interrupt Vectors in AT90CAN128...................................................................... 56
Moving Interrupts Between Application and Boot Space.................................... 59
I/O-Ports............................................................................................... 61
Introduction......................................................................................................... 61
Ports as General Digital I/O................................................................................ 62
Alternate Port Functions..................................................................................... 67
Register Description for I/O-Ports........................................................................85
External Interrupts.............................................................................. 88
Timer/Counter3/1/0 Prescalers.......................................................... 91
Overview............................................................................................................. 91
Timer/Counter0/1/3 Prescalers Register Description ......................................... 92
8-bit Timer/Counter0 with PWM......................................................... 94
Features.............................................................................................................. 94
Overview............................................................................................................. 94
Timer/Counter Clock Sources............................................................................. 95
Counter Unit........................................................................................................ 95
Output Compare Unit.......................................................................................... 96
Compare Match Output Unit................................................................................98
Modes of Operation.............................................................................................99
Timer/Counter Timing Diagrams....................................................................... 102
8-bit Timer/Counter Register Description ......................................................... 104
16-bit Timer/Counter (Timer/Counter1 and Timer/Counter3)........ 108
Features............................................................................................................ 108
Overview........................................................................................................... 108
Accessing 16-bit Registers................................................................................111
Timer/Counter Clock Sources............................................................................115
Counter Unit...................................................................................................... 115
Input Capture Unit............................................................................................. 116
Output Compare Units...................................................................................... 118
Compare Match Output Unit..............................................................................120