DDRB = 0xFF;
 TCCR0A = 0x83;
 TCCR0B = (1 << WGM12);
 TIMSK0 |= (1 << TOIE0);
 TIFR0 |= (1 << OCF0A);
 TCCR0B = (1 << CS10);
 TCNT0 = 0;

 OCR0A = 0x80;

 sei();

 while(1) {

 }