ATmega644PA datasheet(462/468 Pages) ATMEL

462 / 468 page

8152G–AVR–11/09

ATmega164PA/324PA/644PA/1284P

8.4Full Swing Crystal Oscillator ....................................................................................34

8.5Low Frequency Crystal Oscillator ............................................................................35

8.6Calibrated Internal RC Oscillator .............................................................................37

8.7128 kHz Internal Oscillator ......................................................................................38

8.8External Clock .........................................................................................................38

8.9Timer/Counter Oscillator .........................................................................................39

8.10Clock Output Buffer ...............................................................................................39

8.11System Clock Prescaler ........................................................................................39

8.12Register Description ..............................................................................................41

Power Management and Sleep Modes ................................................. 43

9.1Overview .................................................................................................................43

9.2Sleep Modes ...........................................................................................................43

9.3BOD Disable ............................................................................................................44

9.4Idle Mode .................................................................................................................44

9.5ADC Noise Reduction Mode ...................................................................................44

9.6Power-down Mode ..................................................................................................45

9.7Power-save Mode ...................................................................................................45

9.8Standby Mode .........................................................................................................45

9.9Extended Standby Mode .........................................................................................45

9.10Power Reduction Register .....................................................................................46

9.11Minimizing Power Consumption ............................................................................46

9.12Register Description ..............................................................................................48

System Control and Reset .................................................................... 51

10.1Resetting the AVR .................................................................................................51

10.2Internal Voltage Reference ....................................................................................55

10.3Watchdog Timer ....................................................................................................56

10.4Register Description ..............................................................................................59

Interrupts ................................................................................................ 62

11.1Overview ...............................................................................................................62

11.2Interrupt Vectors in ATmega164PA/324PA/644PA/1284P ....................................62

11.3Register Description ..............................................................................................66

External Interrupts ................................................................................. 68

12.1Overview ...............................................................................................................68

12.2Register Description ..............................................................................................68

ATmega644PA Datasheet(PDF) 462 Page - ATMEL Corporation