m820250116ledblink.asm

; (C) David Vajda
; 2025-01-16
; AVR/Atmega8 LED, PORTB, LED Blink

.include "m8def.inc"

ldi r16, HIGH (RAMEND)
out SPH, r16
ldi r16, LOW (RAMEND)
out SPL, r16

ldi r16, 0xff
out DDRB, r16

ldi r16, 0x00
loop1:
dec r16
out PORTB, r16
rcall sleep
rjmp loop1

sleep:
push r16
push r17
ldi r16, 0xff
sleep_loop_outer:
ldi r17, 0xff
sleep_loop_inner:
dec r17
brne sleep_loop_inner
dec r16
brne sleep_loop_outer
pop r17
pop r16
ret