	.Z80
PIO	EQU 0F0H
;
	LD A,0FH
	OUT (PIO+2),A
	OUT (PIO+3),A
	OUT (PIO+6),A
	OUT (PIO+7),A
LOOP:	LD A,0
	OUT (PIO+0),A
	OUT (PIO+1),A
	OUT (PIO+4),A
	OUT (PIO+5),A
	CALL DELAY
	LD A,0FFH
	OUT (PIO+0),A
	OUT (PIO+1),A
	OUT (PIO+4),A
	OUT (PIO+5),A
	CALL DELAY
	JP LOOP
;
DELAY:	LD B,0
DELAY1:	CALL DECR
	DJNZ DELAY1
	RET
;
DECR:	PUSH BC
	LD BC,0
DECR1:	CALL INNER
	DJNZ DECR1
	POP BC
	RET
;
INNER:	PUSH BC
	LD B,04
INNER1:	DJNZ INNER1
	POP BC
	RET
;
	END
