.org $0300

    lda #$1
    sta PBDD     ; set PB0 to output

start:
    lda #248
    sta TIMER_DIV1024 ; start timer mit prescaler => ~2Hz

wait:
    lda TIMER_READ
    bne wait ; Warte, bis timer 0

    ; port B0 umschalten
    lda PBD     ; Read port B
    eor #$01    ; Toggle bit 0
    sta PBD     ; Write back

    jmp start

; MOS6532 PIA addrese $1A80
PBD=$1A82
PBDD=$1A83
TIMER_READ=$1A84 ; timer read register
TIMER_DIV1024=$1A97 ; address to start timer prescaler 1024 and no Interrupt