timer intervall

;; (c) david vajda
;; 07/21/2026
;; m8 timer/counter interrupt

.include "m8def.inc"

.org 0x000
rjmp RESET
.org OVF1addr
rjmp OVF1hndlr

RESET:
ldi r16, HIGH (RAMEND)
out SPH, r16
ldi r16, LOW (RAMEND)
out SPL, r16
ldi r16, 0xff
out DDRB, r16

;; ldi r16, (CS)?? ics csi cis???
;; 2, 1, 0 und kombi

;; jetzt habe ich festgestellt, aber das wusste ich ja
;; CS: heisst, clock select, wie chip select, habe ich ja
;; runter gebetet. allerdings: verwechselt, externes interrupt...
ldi r16, (1 << CS12) | (1 << CS10)
out TCCR1A, r16
ldi r16, (1 << TOIE1)
out TIMSK, r16

sei

ldi r16, 0xff
out PORTB, r16
main001:  rjmp main001

OVF1hndlr:
dec r16
out PORTB, r16
reti