#include  "c:\miniide\hcs12.inc"
		org	$1000
edge_1st	rmb	2			; memory to hold the first edge
period		rmb	2			; memory to store the period
		org	$1500
		movb	#$90,tscr1		; enable timer counter and enable fast timer flags clear
		bclr	tios,IOS0		; enable input capture 0
		movb	#$06,tscr2		; disable TCNT overflow interrupt,  set prescale factor to 64	
		movb	#$01,tctl4		; choose to capture the rising edge of PT0 pin
		movb	#C0F,tflg1		; clear the C0F flag
wait1		brclr	tflg1,C0F,wait1		; wait for the arrival of the first rising edge
		ldd	tc0			; save the  first edge and clear the C0F flag
		std	edge_1st
wait2		brclr	tflg1,C0F,wait2		; wait for the arrival of the second edge
		ldd	tc0
		subd	edge_1st
		std	period
		swi
		end