31 lines
951 B
NASM
31 lines
951 B
NASM
.include "atmega1284definition.asm"
|
|
|
|
; define constant
|
|
.equ LED_PIN = PD7 ; use PD7 as LED pin
|
|
|
|
; start vector
|
|
.org 0x0000
|
|
rjmp main ; jump to main label
|
|
|
|
; main program
|
|
main:
|
|
sbi DDRD, LED_PIN ; set LED pin as output
|
|
loop:
|
|
sbic PIND, LED_PIN ; if bit of LED pin is clear, skip next line
|
|
cbi PORTD, LED_PIN ; if 1, turn the LED off
|
|
sbis PIND, LED_PIN ; if bit of LED pin is set, skip next line
|
|
sbi PORTD, LED_PIN ; if 0, light the LED up
|
|
delay_500ms:
|
|
ldi r20, 32 ; set register, r20 = 32
|
|
delay2:
|
|
ldi r19, 64 ; set register, r19 = 64
|
|
delay1:
|
|
ldi r18, 128 ; set register, r18 = 128
|
|
delay0:
|
|
dec r18 ; decrement register, r18 = r18 - 1
|
|
brne delay0 ; if r18 != 0, jump to label delay0
|
|
dec r19 ; decrement register, r19 = r19 -1
|
|
brne delay1 ; if r19 != 0, jump to label delay1
|
|
dec r20 ; decrement register, r20 = r20 -1
|
|
brne delay2 ; if r20 != 0, jump to label delay2
|
|
rjmp loop ; if r20 == 0, jump to label loop |