65
8271D–AVR–05/11
ATmega48A/PA/88A/PA/168A/PA/328/P
shows reset and Interrupt Vectors placement for the various combina-
tions of BOOTRST and IVSEL settings. If the program never enables an interrupt source, the
Interrupt Vectors are not used, and regular program code can be placed at these locations. This
is also the case if the Reset Vector is in the Application section while the Interrupt Vectors are in
the Boot section or vice versa.
Note:
1. The Boot Reset Address is shown in
. 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
ATmega168A/168PA is:
Address
Labels Code
Comments
0x0000
jmp
RESET
; Reset Handler
0x0002
jmp
EXT_INT0
; IRQ0 Handler
0x0004
jmp
EXT_INT1
; IRQ1 Handler
0x0006
jmp
PCINT0
; PCINT0 Handler
0x0008
jmp
PCINT1
; PCINT1 Handler
0x000A
jmp
PCINT2
; PCINT2 Handler
0x000C
jmp
WDT
; Watchdog Timer Handler
0x000E
jmp
TIM2_COMPA
; Timer2 Compare A Handler
0x0010
jmp
TIM2_COMPB
; Timer2 Compare B Handler
0x0012
jmp
TIM2_OVF
; Timer2 Overflow Handler
0x0014
jmp
TIM1_CAPT
; Timer1 Capture Handler
0x0016
jmp
TIM1_COMPA
; Timer1 Compare A Handler
0x0018
jmp
TIM1_COMPB
; Timer1 Compare B Handler
0x001A
jmp
TIM1_OVF
; Timer1 Overflow Handler
0x001C
jmp
TIM0_COMPA
; Timer0 Compare A Handler
0x001E
jmp
TIM0_COMPB
; Timer0 Compare B Handler
0x0020
jmp
TIM0_OVF
; Timer0 Overflow Handler
0x0022
jmp
SPI_STC
; SPI Transfer Complete Handler
0x0024
jmp
USART_RXC
; USART, RX Complete Handler
0x0026
jmp
USART_UDRE
; USART, UDR Empty Handler
0x0028
jmp
USART_TXC
; USART, TX Complete Handler
0x002A
jmp
ADC
; ADC Conversion Complete Handler
0x002C
jmp
EE_RDY
; EEPROM Ready Handler
0x002E
jmp
ANA_COMP
; Analog Comparator Handler
0x0030
jmp
TWI
; 2-wire Serial Interface Handler
0x0032
jmp
SPM_RDY
; Store Program Memory Ready Handler
;
0x0033RESET:
ldi
r16, high(RAMEND); Main program start
Table 12-5.
Reset and Interrupt Vectors Placement in ATmega168A and ATmega168PA
BOOTRST
IVSEL
Reset Address
Interrupt Vectors Start Address
1
0
0x000
0x002
1
1
0x000
Boot Reset A 0x0002
0
0
Boot Reset Address
0x002
0
1
Boot Reset Address
Boot Reset A 0x0002