334
7530J–AVR–03/12
Atmel ATmega48/88/168 Automotive
6.9
Clock Output Buffer .........................................................................................33
6.10
Timer/Counter Oscillator ..................................................................................33
6.11
System Clock Prescaler ..................................................................................34
7
Power Management and Sleep Modes ................................................. 36
7.1
Idle Mode .........................................................................................................37
7.2
ADC Noise Reduction Mode ............................................................................37
7.3
Power-down Mode ...........................................................................................37
7.4
Power-save Mode ............................................................................................38
7.5
Standby Mode .................................................................................................38
7.6
Power Reduction Register ...............................................................................39
7.7
Minimizing Power Consumption ......................................................................40
8
System Control and Reset .................................................................... 41
8.1
Internal Voltage Reference ..............................................................................46
8.2
Watchdog Timer ..............................................................................................47
9
Interrupts ................................................................................................ 52
9.1
Interrupt Vectors in ATmega48 ........................................................................53
9.2
Interrupt Vectors in ATmega88 ........................................................................54
9.3
Interrupt Vectors in ATmega168 ......................................................................58
10
I/O-Ports .................................................................................................. 62
10.1
Introduction ......................................................................................................62
10.2
Ports as General Digital I/O .............................................................................63
10.3
Alternate Port Functions ..................................................................................68
10.4
Register Description for I/O Ports ....................................................................80
11
External Interrupts ................................................................................. 81
12
8-bit Timer/Counter0 with PWM ............................................................ 86
12.1
Overview ..........................................................................................................86
12.2
Timer/Counter Clock Sources .........................................................................87
12.3
Counter Unit ....................................................................................................87
12.4
Output Compare Unit .......................................................................................88
12.5
Compare Match Output Unit ............................................................................90
12.6
Modes of Operation .........................................................................................91
12.7
Timer/Counter Timing Diagrams .....................................................................95
12.8
8-bit Timer/Counter Register Description ........................................................97