Z80 LED BLINK(8255-PPI)

Z80-LED-BLINK.ASM

;
; PPI LED BLINK FOR Z80 ASM
;
;
PPI_IO	EQU	000H
;
	ORG	8000H
;
MAIN:
	LD	HL,M_MSGE1
	RST	20H
	CALL	MAIN1
;
	RST 	08H	; PGM END
;
MAIN1:
	LD	HL,5			; LOOP COUNT SET
	LD	A,080h
	OUT	(PPI_IO+3),A		; PPI INIT
LOOP:
	LD	A,0FEh
	CALL	OUT_PPI
	LD	A,0FDh
	CALL	OUT_PPI
	LD	A,0FBh
	CALL	OUT_PPI
	LD	A,0F7h
	CALL	OUT_PPI
	LD	A,0EFh
	CALL	OUT_PPI
	LD	A,0DFh
	CALL	OUT_PPI
	LD	A,0BFh
	CALL	OUT_PPI
	LD	A,07Fh
	CALL	OUT_PPI
;
	DEC	HL
	LD	A,L
	OR	H
	JP	Z,END_RTN
;
NEXT:
	JP	LOOP
;
END_RTN:
	LD	A,000h
	CALL	OUT_PPI
	LD	A,0FFh
	CALL	OUT_PPI
	LD	A,000h
	CALL	OUT_PPI
	LD	A,0FFh
	CALL	OUT_PPI
	RET	; GOTO MAIN	
;
OUT_PPI:
	OUT	(PPI_IO),A
	CALL	WAIT1
	RET	
;
WAIT1:
	LD	DE,1000
	CALL	WAIT
	RET
;
WAIT:	
	CALL	WAIT1MS	
	DEC	DE		
	LD	A,D
	OR	E
	JR	NZ,WAIT
	RET		
; 
WAIT1MS:	
	LD	BC,50
WAIT1MSLOOP:
	DEC	BC
	NOP		;DUMMY (clock 4)
	NOP		;DUMMY (clock 4)
	LD	A,C
	OR	B
	JR	NZ,WAIT1MSLOOP
	RET
;
CR	EQU	0DH
LF	EQU	0AH
;
M_MSGE1	DB	"*** i8255 LED BLINK ***",CR,0
;
END