Datasheet

11.5. I/O Memory.................................................................................................................................32
11.6. Register Description................................................................................................................... 32
12. System Clock and Clock Options............................................................................ 39
12.1. Clock Systems and their Distribution..........................................................................................39
12.2. Clock Sources............................................................................................................................ 40
12.3. Default Clock Source..................................................................................................................41
12.4. Crystal Oscillator........................................................................................................................ 41
12.5. Low-frequency Crystal Oscillator................................................................................................42
12.6. External RC Oscillator................................................................................................................ 43
12.7. Calibrated Internal RC Oscillator................................................................................................43
12.8. External Clock............................................................................................................................ 44
12.9. Timer/Counter Oscillator.............................................................................................................45
12.10. Register Description...................................................................................................................45
13. Power Management and Sleep Modes................................................................... 47
13.1. Sleep Modes...............................................................................................................................47
13.2. Idle Mode....................................................................................................................................48
13.3. ADC Noise Reduction Mode.......................................................................................................48
13.4. Power-down Mode......................................................................................................................48
13.5. Power-save Mode.......................................................................................................................48
13.6. Standby Mode............................................................................................................................ 49
13.7. Extended Standby Mode............................................................................................................ 49
13.8. Minimizing Power Consumption................................................................................................. 49
13.9. Register Description................................................................................................................... 51
14. System Control and Reset.......................................................................................53
14.1. Resetting the AVR...................................................................................................................... 53
14.2. Reset Sources............................................................................................................................53
14.3. Internal Voltage Reference.........................................................................................................57
14.4. Watchdog Timer......................................................................................................................... 57
14.5. Register Description................................................................................................................... 58
15. Interrupts................................................................................................................. 62
15.1. Interrupt Vectors in ATmega32A.................................................................................................62
15.2. Register Description................................................................................................................... 66
16. External Interrupts................................................................................................... 69
16.1. Register Description................................................................................................................... 69
17. I/O Ports.................................................................................................................. 74
17.1. Overview.....................................................................................................................................74
17.2. Ports as General Digital I/O........................................................................................................75
17.3. Alternate Port Functions.............................................................................................................78
17.4. Register Description................................................................................................................... 88
18. Timer/Counter0 and Timer/Counter1 Prescalers...................................................102
18.1. Overview...................................................................................................................................102
18.2. Internal Clock Source............................................................................................................... 102
Atmel ATmega32A [DATASHEET]
Atmel-8155I-ATmega32A_Datasheet_Complete-08/2016
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