ATmega32U2 datasheet(308/314 Pages) ATMEL

308 / 314 page

7799B–AVR–07/09

ATmega8U2/16U2/32U2

8.8Clock Output Buffer .................................................................................................35

8.9System Clock Prescaler ..........................................................................................35

8.10PLL ........................................................................................................................36

8.11Register Description ..............................................................................................37

Power Management and Sleep Modes ................................................. 42

9.1Overview ..................................................................................................................42

9.2Sleep Modes ............................................................................................................42

9.3Idle Mode .................................................................................................................42

9.4Power-down Mode ...................................................................................................43

9.5Power-save Mode ....................................................................................................43

9.6Standby Mode .........................................................................................................43

9.7Extended Standby Mode .........................................................................................43

9.8Power Reduction Register .......................................................................................43

9.9Minimizing Power Consumption ..............................................................................44

9.10Register Description ..............................................................................................45

System Control and Reset .................................................................... 47

10.1Resetting the AVR .................................................................................................47

10.2Reset Sources .......................................................................................................47

10.3Internal Voltage Reference ....................................................................................51

10.4Watchdog Timer ....................................................................................................51

10.5Register Description ..............................................................................................55

Interrupts ................................................................................................ 64

11.1Overview ................................................................................................................64

11.2Interrupt Vectors in ATmega8U2/16U2/32U2 ........................................................64

11.3Register Description ..............................................................................................65

I/O-Ports .................................................................................................. 67

12.1Overview ................................................................................................................67

12.2Ports as General Digital I/O ...................................................................................68

12.3Alternate Port Functions ........................................................................................72

12.4Register Description for I/O-Ports ..........................................................................82

External Interrupts ................................................................................. 84

13.1Overview ................................................................................................................84

13.2Register Description ..............................................................................................84

Timer/Counter0 and Timer/Counter1 Prescalers ................................ 88

ATmega32U2 Datasheet(PDF) 308 Page - ATMEL Corporation