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Reset and interrupt handling – Rainbow Electronics ATmega103L User Manual

Page 24

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ATmega603/103

24

Reset and Interrupt Handling

The ATmega603/103 provides 23 different interrupt sources. These interrupts and the separate reset vector each have a
separate program vector in the program memory space. All interrupts are assigned individual enable bits which must be set
(one) together with the I-bit in the status register in order to enable the interrupt.

The lowest addresses in the program memory space are automatically defined as the Reset and Interrupt vectors. The
complete list of vectors is shown in Table 5. The list also determines the priority levels of the different interrupts. The lower
the address the higher is the priority level. RESET has the highest priority, and next is INT0 - the External Interrupt Request
0 etc.

Table 5. Reset and Interrupt Vectors

Vector No.

Program Address

Source

Interrupt Definition

1

$0000

RESET

Hardware Pin, Power-on Reset and Watchdog Reset

2

$0002

INT0

External Interrupt Request 0

3

$0004

INT1

External Interrupt Request 1

4

$0006

INT2

External Interrupt Request 2

5

$0008

INT3

External Interrupt Request 3

6

$000A

INT4

External Interrupt Request 4

7

$000C

INT5

External Interrupt Request 5

8

$000E

INT6

External Interrupt Request 6

9

$0010

INT7

External Interrupt Request 7

10

$0012

TIMER2 COMP

Timer/Counter2 Compare Match

11

$0014

TIMER2 OVF

Timer/Counter2 Overflow

12

$0016

TIMER1 CAPT

Timer/Counter1 Capture Event

13

$0018

TIMER1 COMPA

Timer/Counter1 Compare Match A

14

$001A

TIMER1 COMPB

Timer/Counter1 Compare Match B

15

$001C

TIMER1 OVF

Timer/Counter1 Overflow

16

$001E

TIMER0 COMP

Timer/Counter0 Compare Match

17

$0020

TIMER0 OVF

Timer/Counter0 Overflow

18

$0022

SPI, STC

SPI Serial Transfer Complete

19

$0024

UART, RX

UART, Rx Complete

20

$0026

UART, UDRE

UART Data Register Empty

21

$0028

UART, TX

UART, Tx Complete

22

$002A

ADC

ADC Conversion Complete

23

$002C

EE READY

EEPROM Ready

24

$002E

ANALOG COMP

Analog Comparator