1602液晶屏驅動源程序9 
     

      ;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 0060H
      MAIN:
      MOV TMOD,#00H
      MOV TL0,#00H
      MOV TH0,#00H
      SETB EA
      SETB ET0
      CLR TR0
      MOV R7,#250
      CLR 0FH ;if 2s time reach,setb 0fh.


      MOV SP,#70H
      START: 
      LCALL INITIAL
      MOV A,#10000000B
      LCALL WRITE_INSTRUCTION
      MOV DPTR,#TAB1
      LCALL KEY 
      MOV 50H,A 
      TT:
      MOVC A,@A+DPTR
      LCALL CLS 
      LCALL WRITELCDDATA
      LCALL KEY
      ;LCALL INSERS
      SETB TR0
      JBC 0FH,START ;
      CLR TR0
      MOV TL0,#00H
      MOV TH0,#00H
      MOV R7,#250

      ;LCALL CLS ;
      CJNE A,50H,TT ;
      MOV DPTR,#TAB2
      MOVC A,@A+DPTR 
      ;LCALL CLS 
      LCALL WRITELCDDATA
      AJMP START

      INSERS:
      MOV TL0,#00H
      MOV TH0,#00H
      DJNZ R7,L0
      MOV R7,#250
      CPL 0FH
      CLR TR0 ;2S time reach,stop count time.
      L0:
      RETI

      CLS:
      PUSH ACC
      MOV A,#01H
      LCALL WRITE_INSTRUCTION
      POP ACC
      RET

      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,#08H
      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
      SETB TR0 ;begin count time.

      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,#01H
      L7: MOV R6,#4AH
      L8: DJNZ R6,L8
      DJNZ R5,L7
      RET
      TAB1:DB 31H,32H,33H,34H,35H,36H,37H,38H,39H
      DB 41H,30H,42H
      TAB2:DB 43H,44H,45H,46H,47H,48H,49H,4AH,4BH
      DB 4CH,4DH,4EH
      TT: 
      END