4x4按鍵與LCD應用 8051 assembly

	;------------------------------------------
	; ==================================
	; == 4x4按鍵與lcd應用 ==
	; == 2014/12/28 ==
	; == 蘇偉諺 4a037052 ==
	; ==================================
	;------------------------------------------
	;
	;於lcd的第一列顯示'0123456789abcdef'並利用4x4keyport按鍵，按下數字後其lcd上相對應的數字會往下跳至第二列
	lcd_rs equ p2.1
	lcd_enable equ p3.7
	lcd_bus equ p0
	keypor equ p2
	keyflag equ 20h.2
	scancode equ 33h
	keyno equ 34h
	org 00h
	mov sp,#5fh
	call initlcd
	mov dptr,#str
	call prtstring
	again: call keyin
	jnb keyflag,again
	push acc;;;;;;;;;;;;;;
	mov b,a
	mov a,#1
	call goxy
	mov a,#20h
	call wrdr
	mov a,#2
	call goxy
	pop acc;;;;;;;;;;;;;;
	mov dptr,#str;;;;;;
	movc a,@a+dptr
	call wrdr
	jmp again
	str: db '0123456789ABCDEF','$'
	keyin: push 00
	push 01
	mov r0,#0
	mov scancode,#11111110b
	keyrow: mov keyport,scancode
	mov r7,#4
	call delay
	mov a,keyport
	mov r1,#4
	swap a
	kcol: rrc a
	jnc keypressed
	inc r0
	djnz r1,kcol
	mov a,scancode
	rl a
	mov scancode,a
	jnb acc.4,nokey;;;;;;;;;;;;;;;;;;;;
	jmp keyrow
	nokey: clr keyflag
	jmp keyend
	keypressed: mo a,r0
	setb keyflag
	keyend: pop 01
	pop 00
	ret
	goxy: anl b,#00001111b
	cjne a,#1,chk1
	mov a,b
	add a,#10000000b;setb a.7 orl 10000000b
	call wrir
	ret
	chk1: mov a,b
	add a,#11000000b
	call wrir
	ret
	prtstring: push acc
	prtloop: clr a
	movc a,@a+dptr
	cjne a,#'$',next
	jmp endprt
	next: call wrdr
	inc dptr
	jmp prtloop
	endprt: pop acc
	ret
	initlcd: mov a,#38h
	call wrir
	mov a,#0dh
	call wrir
	mov a,#06h
	call wrir
	clrlcd: mov a,#01h
	call wrir
	mov r7,#40;清除需延遲2ms
	call delay
	ret
	delay: mov tmod,#00010001b
	dloop: mov th0,#high(65536-50)
	mov tl0,#low(65536-50)
	setb tr0
	jnb tf0,$
	clr tr0
	clr tf0
	djnz r7,dloop
	ret
	wrir: setb lcd_enable
	clr lcd_rs
	mov lcd_bus,a
	clr lcd_enable
	mov r7,#1
	call delay
	ret
	wrdr: setb lcd_enable
	setb lcd_rs
	mov lcd_bus,a
	clr lcd_enable
	mov r7,#1
	call delay
	ret
	end

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