1602液晶屏驱动源程序2

;lcd display program
RS BIT P2.6
R_W BIT P2.5
ENABLE BIT P2.7 
LCDDATA DATA P1


;******************************************

ORG 0000H
AJMP MAIN
;ORG 000BH
;AJMP INSERS

ORG 0050H
MAIN:
;MOV TMOD,#00H
;MOV TL0,#00H
;MOV TH0,#00H
;SETB EA
;SETB ET0
;SETB TR0
;MOV R5,#50
;CLR P3.2
;SETB P3.1


MOV SP,#60H
START: 
LCALL INITIAL
MOV A,#10000000B
LCALL WRITE_INSTRUCTION
MOV DPTR,#TAB
LCALL KEY
MOVC A,@A+DPTR
LCALL WRITELCDDATA
AJMP START

;INSERS:
;MOV TL0,#00H
;MOV TH0,#00H
;DJNZ R5,L0
;MOV R5,#50
;CPL P3.2
;CPL P3.1
;L0:
;RETI

INITIAL:
MOV A,#00111000B
LCALL WRITE_INSTRUCTION
MOV A,#00001110B
LCALL WRITE_INSTRUCTION
MOV A,#00000110B
LCALL WRITE_INSTRUCTION
RET

CHECKBUSY:
PUSH ACC
CHECKBUSYLOOP:
CLR ENABLE
SETB R_W
CLR RS
SETB ENABLE
MOV A,LCDDATA
CLR ENABLE
JB ACC.7,CHECKBUSYLOOP
POP ACC
LCALL DELAY1
RET

WRITE_INSTRUCTION:
LCALL CHECKBUSY
CLR ENABLE
CLR R_W
CLR RS 
SETB ENABLE
MOV LCDDATA,A
CLR ENABLE
RET

WRITELCDDATA:
LCALL CHECKBUSY
CLR ENABLE
CLR R_W
SETB RS
SETB ENABLE
MOV LCDDATA,A
CLR ENABLE
RET




DELAY1:
MOV R5,#05H
L4:
MOV R6,#0F8H
L5:
DJNZ R6,L5
DJNZ R5,L4
RET

KEY: LCALL KS
JNZ K1
LCALL DELAY2
AJMP KEY
K1: LCALL DELAY2
LCALL DELAY2
LCALL KS
JNZ K2
AJMP KEY
K2: MOV R2,#0DFH
MOV R4,#00H
K3: MOV P3,R2
L6: JB P3.0,L1 
MOV A,#00H
AJMP LK
L1: JB P3.1,L2
MOV A,#03H
AJMP LK
L2: JB P3.2,L3 
MOV A,#06H
AJMP LK
L3: JB P3.3,NEXT
MOV A,#09H
LK: ADD A,R4
PUSH ACC
K4: LCALL DELAY2
LCALL KS
JNZ K4
POP ACC
RET

NEXT:
INC R4
MOV A,R2
JNB ACC.7,KEY
RL A
MOV R2,A
AJMP K3
KS: MOV P3,#0FH
MOV A,P3
XRL A,#0FH
RET
DELAY2:
MOV R5,#4AH
L7: MOV R6,#0FAH
L8: DJNZ R6,L8
DJNZ R5,L7
RET
TAB:DB 31H,32H,33H,34H,35H,36H,37H,38H,39H
DB 41H,30H,42H
END