LCD 應用控制 8051 assembly

	;------------------------------------------
	; ===================================
	; == lcd 應用控制 ==
	; == 2014/12/29 ==
	; == 蘇偉諺 4a037052 ==
	; ===================================
	;------------------------------------------
	;開機後，lcd第一列顯示'0123456789abcdef'，並閃爍3次，接著每個字元依序跳至第二列顯示
	;-----------------------------------------------------------------------------
	; parameter define
	;-----------------------------------------------------------------------------
	lcd_enable equ p3.7
	lcd_rs equ p2.1
	lcd_bus equ p0
	;-----------------------------------------------------------------------------
	; main program
	;-----------------------------------------------------------------------------
	org 00h
	mov sp,#5fh
	call initlcd
	; call clrlcd
	; mov r7,#20
	; call delay50ms
	; mov dptr,#str
	; call prtstring
	; mov r7,#20
	; call delay50ms
	; call clrlcd
	; mov r7,#20
	; call delay50ms
	; mov dptr,#str
	; call prtstring
	; mov r7,#20
	; call delay50ms
	; call clrlcd
	; mov r7,#20
	; call delay50ms
	; mov dptr,#str
	; call prtstring
	; mov r7,#20
	; call delay50ms
	mov r5,#3
	glint: call clrlcd;;;;;;;
	mov r7,#20
	call delay50ms
	mov dptr,#str
	call prtstring
	mov r7,#20
	call delay50ms
	djnz r5,glint
	; mov a,#1
	; mov b,#0
	; call goxy
	; mov a,#20h
	; call wrdr
	; mov a,#2
	; mov b,#0
	; call goxy
	; mov dptr,#str
	; mov a,#0
	; movc a,@a+dptr
	; call wrdr
	; mov a,#1
	; mov b,#1
	; call goxy
	; mov a,#20h
	; call wrdr
	; mov a,#2
	; mov b,#1
	; call goxy
	; mov dptr,#str
	; mov a,#1
	; movc a,@a+dptr
	; call wrdr
	mov r3,#0
	mov dptr,#str
	appear: mov a,#1
	mov b,r3
	call goxy
	mov a,#20h
	call wrdr
	mov a,#2
	mov b,r3
	call goxy
	mov a,r3
	movc a,@a+dptr
	call wrdr
	inc r3
	mov r7,#20
	call delay50ms
	cjne r3,#16,appear
	jmp $
	str: db '0123456789abcdef','$'
	;-----------------------------------------------------------------------------
	; display string
	;-----------------------------------------------------------------------------
	prtstring: push acc ;
	prtloop: clr a ;
	movc a,@a+dptr ;
	cjne a,#'$',next ;
	sjmp endprt ;
	next: acall wrdr ;
	inc dptr ;
	jmp prtloop ;
	endprt: pop acc ;
	ret ;
	;-----------------------------------------------------------------------------
	; initial lcd
	;-----------------------------------------------------------------------------
	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
	;-----------------------------------------------------------------------------
	; go x line, y char
	;-----------------------------------------------------------------------------
	goxy: anl b,#00001111b ;
	cjne a,#1,chk1 ;
	mov a,b ;
	add a,#10000000b ;
	call wrir ;
	ret ;
	chk1: mov a,b ;
	add a,#11000000b ;
	call wrir ;
	ret ;
	;-----------------------------------------------------------------------------
	; write control word to instruction register
	;-----------------------------------------------------------------------------
	wrir: clr lcd_rs ;
	setb lcd_enable ;
	mov lcd_bus,a ;
	clr lcd_enable ;
	mov r7,#1 ;
	call delay ;delay 50us
	ret ;
	;-----------------------------------------------------------------------------
	; write data to data register
	;-----------------------------------------------------------------------------
	wrdr: setb lcd_rs ;
	setb lcd_enable ;
	mov lcd_bus,a ;
	clr lcd_enable ;
	mov r7,#1 ;
	call delay ;delay 50us
	ret ;
	;-------------------------------------------------------------------------------
	; delay time=r7*0.05ms
	;-------------------------------------------------------------------------------
	delay: mov tmod,#00010001b ;timer 0 : mode 1
	loopdy: mov th0,#high(65536-50);
	mov tl0,#low(65536-50);
	setb tr0 ;
	wait: jnb tf0,wait ;
	clr tf0 ;
	clr tr0 ;
	djnz r7,loopdy ;
	ret ;
	;-------------------------------------------------------------------------------
	; delay time=r7*50ms
	;-------------------------------------------------------------------------------
	delay50ms:
	loopdy1: mov th0,#high(65536-50000)
	mov tl0,#low(65536-50000)
	setb tr0
	jnb tf0,$
	clr tf0
	clr tr0
	djnz r7,loopdy1
	ret
	end

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