ATMEGA8_08 Datasheet, PDF (47/308 Pages) ATMEL Corporation – 8-bit with 8K Bytes In-System Programmable Flash

ATmega8(L)
Table 19. Reset and Interrupt Vectors Placement
BOOTRST⁽¹⁾ IVSEL Reset Address
Interrupt Vectors Start Address
1
0
0x000
0x001
1
1
0x000
Boot Reset Address + 0x001
0
0
Boot Reset Address
0x001
0
1
Boot Reset Address
Boot Reset Address + 0x001
Note: 1. The Boot Reset Address is shown in Table 82 on page 220. For the BOOTRST Fuse “1”
means unprogrammed while “0” means programmed.
The most typical and general program setup for the Reset and Interrupt Vector Addresses in
ATmega8 is:
addressLabels Code
Comments
$000
rjmp RESET
; Reset Handler
$001
rjmp EXT_INT0
; IRQ0 Handler
$002
rjmp EXT_INT1
; IRQ1 Handler
$003
rjmp TIM2_COMP
; Timer2 Compare Handler
$004
rjmp TIM2_OVF
; Timer2 Overflow Handler
$005
rjmp TIM1_CAPT
; Timer1 Capture Handler
$006
rjmp TIM1_COMPA
; Timer1 CompareA Handler
$007
rjmp TIM1_COMPB
; Timer1 CompareB Handler
$008
rjmp TIM1_OVF
; Timer1 Overflow Handler
$009
rjmp TIM0_OVF
; Timer0 Overflow Handler
$00a
rjmp SPI_STC
; SPI Transfer Complete Handler
$00b
rjmp USART_RXC
; USART RX Complete Handler
$00c
rjmp USART_UDRE
; UDR Empty Handler
$00d
rjmp USART_TXC
; USART TX Complete Handler
$00e
rjmp ADC
; ADC Conversion Complete Handler
$00f
rjmp EE_RDY
; EEPROM Ready Handler
$010
rjmp ANA_COMP
; Analog Comparator Handler
$011
rjmp TWSI
; Two-wire Serial Interface Handler
$012
rjmp SPM_RDY
; Store Program Memory Ready Handler
;
$013 RESET: ldi
r16,high(RAMEND); Main program start
$014
out SPH,r16
; Set Stack Pointer to top of RAM
$015
ldi r16,low(RAMEND)
$016
out SPL,r16
$017
sei
; Enable interrupts
$018
<instr> xxx
...
...
...
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2486T–AVR–05/08