Datasheet

16. Interrupts
This section describes the specifics of the interrupt handling of the device. For a general explanation of
the AVR interrupt handling, refer to the description of Reset and Interrupt Handling.
The interrupt vectors in ATmega48PA/88PA/168PA are generally the same, with the following differences:
• Each interrupt vector occupies two instruction words ATmega168PA ; and one instruction word in
ATmega48PA and ATmega88PA.
• ATmega48PA does not have a separate boot loader section. In ATmega88PA and ATmega168PA
the Reset vector is affected by the BOOTRST fuse, and the interrupt vector start address is
affected by the IVSEL bit in MCUCR
16.1 Interrupt Vectors in ATmega48PA
Table 16-1. Reset and Interrupt Vectors in ATmega48PA
Vector No
Program Address Source Interrupts definition
1 0x0000 RESET External Pin, Power-on Reset, Brown-out Reset and Watchdog System
Reset
2 0x0001 INT0 External Interrupt Request 0
3 0x0002 INT1 External Interrupt Request 0
4 0x0003 PCINT0 Pin Change Interrupt Request 0
5 0x0004 PCINT1 Pin Change Interrupt Request 1
6 0x0005 PCINT2 Pin Change Interrupt Request 2
7 0x0006 WDT Watchdog Time-out Interrupt
8 0x0007 TIMER2_COMPA Timer/Counter2 Compare Match A
9 0x0008 TIMER2_COMPB Timer/Coutner2 Compare Match B
10 0x0009 TIMER2_OVF Timer/Counter2 Overflow
11 0x000A TIMER1_CAPT Timer/Counter1 Capture Event
12 0x000B TIMER1_COMPA Timer/Counter1 Compare Match A
13 0x000C TIMER1_COMPB Timer/Coutner1 Compare Match B
14 0x000D TIMER1_OVF Timer/Counter1 Overflow
15 0x000E TIMER0_COMPA Timer/Counter0 Compare Match A
16 0x000F TIMER0_COMPB Timer/Coutner0 Compare Match B
17 0x0010 TIMER0_OVF Timer/Counter0 Overflow
18 0x0011 SPI STC SPI Serial Transfer Complete
19 0x0012 USART_RX USART Rx Complete
20 0x0013 USART_UDRE USART Data Register Empty
21 0x0014 USART_TX USART Tx Complete
22 0x0015 ADC ADC Conversion Complete
ATmega48PA/88PA/168PA
Interrupts
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Datasheet Complete
DS40002011A-page 88