jianpan.txt

实现PIC16F877的键盘控制液晶显示功能

status		equ	3h
z		equ	2h
rp0		equ	5h
rp1		equ	6h
portb		equ	6h
trisb		equ	86h
portc		equ	7h
trisc		equ	87h
portd		equ	8h
trisd		equ	88h
fsr		equ	04h
option_reg	equ	81h
rbup		equ	7
data1		equ	20h
data2		equ	21h
n2		equ	0ffh
value		equ	22h
table		equ	40h


	org	0000h
	nop
	bcf	status,rp1
	bsf	status,rp0

	movlw	00h
	movwf	trisc


	movlw	0ffh
	movwf	trisb
	bcf	status,rp0
	movlw	0f0h
	movwf	portc

	movlw	77h
	movwf	40h
	movlw	0b7h
	movwf	41h
	movlw	0d7h
	movwf	42h
	movlw	0e7h
	movwf	43h
	movlw	7bh
	movwf	44h
	movlw	0bbh
	movwf	45h
	movlw	0dbh
	movwf	46h
	movlw	0ebh
	movwf	47h
	movlw	7dh
	movwf	48h
	movlw	0bdh
	movwf	49h
	movlw	0ddh
	movwf	4ah
	movlw	0edh
	movwf	4bh
	movlw	7eh
	movwf	4ch
	movlw	0beh
	movwf	4dh
	movlw	0deh
	movwf	4eh
	movlw	0eeh
	movwf	4fh

check
	call	keyscan
	comf	value,0
	btfsc	status,z
	goto	check
	movlw	.13
	movwf	data1
	call	delay
	call	keyscan
	comf	value,0
	btfsc	status,z
	goto	check
	call	translate
	movf	fsr,0
	movwf	portc

check1
	movlw	.117
	movwf	data1
	call	delay
	movlw	0f0h
	xorwf	portc,1
	call	keyscan
	comf	value,0
	btfss	status,z
	goto	check1
	goto	check

keyscan                           
                                 
 bsf	status,rp0                            
 bcf option_reg,7                 

 movlw 0fh                        
 movwf trisd
 movlw 0ffh                       
 movwf trisb

 bcf 	status,rp0                         
 movlw 00h                          
 movwf portd
 nop
 nop
 movf portb,0                 
 andlw 0fh                    
 movwf value                     
 xorlw 0fh                        
 btfsc status,2                 
 goto nokey                      

 bsf	status,rp0                           
 movlw 0f0h
 movwf trisd                    
 movlw 0f0h
 movwf trisb                      
 bcf	status,rp0                             
 movf value,0                     
 movwf portb                      
 nop                              
 nop
 movf portd,0                     
 andlw 0f0h                       
 iorwf value,1                   
 return
nokey                             
 movlw 0ffh
 movwf value
 return



translate
	movlw	40h
	movwf	fsr
loopt1
	movf	0,0
	xorwf	value,0
	btfsc	status,z
	goto	loopt2
	incf	fsr,1
	btfss	fsr,4
	goto	loopt1
	movlw	0aah
	movwf	fsr
	return
loopt2
	bcf	fsr,6
	return

delay
lp0	movlw 	n2
	movwf	data2
lp1	decfsz	data2,1
 	goto	lp1
	decfsz	data1,1
	goto	lp0
	return
	end