/*

SLdt  240704          Disclaimer: none. Sue me.

"ATtiny25, USI clock vom Timer0 compare match":
https://www.mikrocontroller.net/topic/62429#new

avrasm2
*/

.include    "tn85def.inc"

.def    tmp0    = r16

.org    $0000
    rjmp        reset

.org    OC0Baddr
    sbi     PINB,3                                      ; zur Kontrolle
    reti

.org    USI_OVFaddr
    sbi     PINB,4
    in      tmp0,USISR
    out     USISR,tmp0
    reti
;******************************************************

reset:
    sbi     DDRB,3                                      ; Kontroll-LED: Timer/Counter Output Compare Match B Interrupt
    sbi     DDRB,4                                      ; Kontroll-LED: USI - Timer/Counter0 Compare Match
    ldi     tmp0,140
    out     OCR0A,tmp0
    ldi     tmp0,130 ;150
    out     OCR0B,tmp0
    ldi     tmp0,(1<<WGM01)                             ; CTC
    out     TCCR0A,tmp0
    ldi     tmp0,(1<<CS02)+(0<<CS00)
    out     TCCR0B,tmp0
    ldi     tmp0,(1<<OCIE0B)
    out     TIMSK,tmp0
    ldi     tmp0,(1<<USIOIE)+(1<<USICS0)
    out     USICR,tmp0

    sei
main_loop:
  rjmp      main_loop