#include "c:\miniide\hcs12.inc"

	org	$1000
count	ds.b	1		; reserve one byte for count
	org	$1500
	lds	#$1500		; set up the stack pointer
	clr	count
	movb	#$FF,ddrb	; configure port B for output
	movb	count,portb	; display the count value on LEDs
	movb	#$C0,irqcr	; enable IRQ pin interrupt and select edge-triggering
	cli			; 	"
forever	nop
	bra	forever		; wait for IRQ pin interrupt
irq_isr	inc	count		; increment count
	movb	count,portb	; and display it
	rti
	org	UserIRQ		; establish IRQ interrupt vector entry
	fdb	irq_isr
	end