ATmega48/88/168
0x0034
RAM
out
SPH,r16
; Set Stack Pointer to top of
0x0035
0x0036
0x0037
0x0038
...
ldi
out
sei
r16, low(RAMEND)
SPL,r16
; Enable interrupts
<instr> xxx
... ...
...
When the BOOTRST Fuse is unprogrammed, the Boot section size set to 2K bytes and
the IVSEL bit in the MCUCR Register is set before any interrupts are enabled, the most
typical and general program setup for the Reset and Interrupt Vector Addresses in
ATmega168 is:
Address Labels Code
Comments
0x0000 RESET: ldi
r16,high(RAMEND); Main program start
0x0001
RAM
out
ldi
SPH,r16
; Set Stack Pointer to top of
0x0002
r16,low(RAMEND)
SPL,r16
0x0003
0x0004
out
sei
; Enable interrupts
0x0005
;
<instr> xxx
.org 0xC02
0x1C02
0x1C04
...
jmp
jmp
...
jmp
EXT_INT0
; IRQ0 Handler
EXT_INT1
...
; IRQ1 Handler
;
0x1C32
SPM_RDY
; Store Program Memory Ready
Handler
When the BOOTRST Fuse is programmed and the Boot section size set to 2K bytes, the
most typical and general program setup for the Reset and Interrupt Vector Addresses in
ATmega168 is:
Address Labels Code
Comments
.org 0x0002
0x0002
0x0004
...
jmp
jmp
...
jmp
EXT_INT0
EXT_INT1
...
; IRQ0 Handler
; IRQ1 Handler
;
0x0032
SPM_RDY
; Store Program Memory Ready
Handler
;
.org 0x1C00
0x1C00 RESET: ldi
r16,high(RAMEND); Main program start
0x1C01
RAM
out
SPH,r16
; Set Stack Pointer to top of
0x1C02
ldi
r16,low(RAMEND)
SPL,r16
0x1C03
0x1C04
out
sei
; Enable interrupts
0x1C05
<instr> xxx
When the BOOTRST Fuse is programmed, the Boot section size set to 2K bytes and the
IVSEL bit in the MCUCR Register is set before any interrupts are enabled, the most typ-
ical and general program setup for the Reset and Interrupt Vector Addresses in
ATmega168 is:
59
2545D–AVR–07/04
ATMEL [ ATMEL ]
