.INCLUDE "tn13def.inc"

; data direction = output
	sbi DDRB, 1 ; PB1

loop:

; clear bit
	cbi PORTB, 1

; wait
; takes roughly ((2+2)*(256*256))/(9.6*1000*1000/8) ~ .218 seconds.
; 2 cycles SBIW + 2 cycles BRNE for 256*256 subtractions
; 9.6 MHz (CKSEL[1..0] = 10) with CKDIV=8
loop1:
 	sbiw ZL, 1
	brne loop1

; set bit
	sbi PORTB, 1

; wait
loop2:
	sbiw ZL, 1
	brne loop2

; again! again! again!
	rjmp loop