Datasheet

iii
2549O–AVR–05/12
ATmega640/1280/1281/2560/2561
14.1 Interrupt Vectors in ATmega640/1280/1281/2560/2561 ................................105
14.2 Reset and Interrupt Vector placement ...........................................................107
14.3 Moving Interrupts Between Application and Boot Section .............................109
14.4 Register Description ......................................................................................110
15 External Interrupts ............................................................................... 112
15.1 Pin Change Interrupt Timing ..........................................................................112
15.2 Register Description ......................................................................................113
16 8-bit Timer/Counter0 with PWM .......................................................... 118
16.1 Features ........................................................................................................118
16.2 Overview ........................................................................................................118
16.3 Timer/Counter Clock Sources .......................................................................119
16.4 Counter Unit ..................................................................................................119
16.5 Output Compare Unit .....................................................................................120
16.6 Compare Match Output Unit ..........................................................................122
16.7 Modes of Operation .......................................................................................123
16.8 Timer/Counter Timing Diagrams ...................................................................127
16.9 Register Description ......................................................................................129
17 16-bit Timer/Counter (Timer/Counter 1, 3, 4, and 5) .......................... 136
17.1 Features ........................................................................................................136
17.2 Overview ........................................................................................................136
17.3 Accessing 16-bit Registers ............................................................................138
17.4 Timer/Counter Clock Sources .......................................................................141
17.5 Counter Unit ..................................................................................................142
17.6 Input Capture Unit .........................................................................................143
17.7 Output Compare Units ...................................................................................145
17.8 Compare Match Output Unit ..........................................................................147
17.9 Modes of Operation .......................................................................................148
17.10 Timer/Counter Timing Diagrams ...................................................................156
17.11 Register Description ......................................................................................158
18 Timer/Counter 0, 1, 3, 4, and 5 Prescaler ........................................... 169
18.1 Internal Clock Source ....................................................................................169
18.2 Prescaler Reset .............................................................................................169
18.3 External Clock Source ...................................................................................169
18.4 Register Description ......................................................................................170