實驗要求：利用P1口與行列式鍵盤接口，編寫鍵盤掃描程序，把按鍵輸入的鍵碼，顯示在LCD液晶顯示器上。
//This is the seventh program of the homework;
//This program is made by Wang Qi Date:2013/3/7
ORG 0000H
sjmp main
org 0050h
//
sbit lcdrs=P1^0;   // 液晶數據/命令選擇端口
sbit lcden=P2^5;   // 液晶使能端
sbit lcdrw=P1^1;   //讀寫選擇端口
sbit wei=P2^7;
sbit duan=P2^6;
//
MAIN:
         CALL INTE
         MOV DPTR,#TABLE   
SCAN:   //檢測第一行
   MOV P3,#0FEH;
   MOV A,P3
   ANL A,#0F0H
XHPD0:   CJNE A,#0F0H,OK0
   SJMP NO1
OK0:     CALL DELAY0
   MOV A,P3
   ANL A,#0F0H
   CJNE A,#0F0H,MM0
   SJMP XHPD0
MM0:     CJNE A,#0E0H,MM1
      MOV R1,#01H
   CALL JIEDIAN
MM1:     CJNE A,#0D0H,MM2
      MOV R1,#02H
      CALL JIEDIAN
MM2:     CJNE A,#0B0H,MM3
   MOV R1,#03H
   CALL JIEDIAN
MM3:     CJNE A,#070H,XHPD0
      MOV R1,#04H
   CALL JIEDIAN
 
      //檢測第二行
NO1:     MOV P3,#0FDH;
      MOV A,P3
      ANL A,#0F0H
XHPD1:   CJNE A,#0F0H,OK1
    //CALL  JIEDIAN
      SJMP NO2
OK1:     CALL DELAY0
         MOV A,P3
      ANL A,#0F0H
         CJNE A,#0F0H,MM00
      SJMP XHPD1
MM00:    CJNE A,#0E0H,MM10
         MOV R1,#05H
      CALL JIEDIAN
MM10:    CJNE A,#0D0H,MM20
         MOV R1,#06H
      CALL JIEDIAN
MM20:    CJNE A,#0B0H,MM30
      MOV R1,#07H
      CALL JIEDIAN
MM30:    CJNE A,#070H,XHPD1
         MOV R1,#08H
         CALL JIEDIAN
         //檢測第三行
NO2:     MOV P3,#0FBH;
      MOV A,P3
      ANL A,#0F0H
XHPD2:   CJNE A,#0F0H,OK2
         SJMP NO3
OK2:     CALL DELAY0
         MOV A,P3
      ANL A,#0F0H
         CJNE A,#0F0H,MM01
      SJMP XHPD2
MM01:    CJNE A,#0E0H,MM11
         MOV R1,#09H
      CALL JIEDIAN
MM11:    CJNE A,#0D0H,MM21
         MOV R1,#0AH
      CALL JIEDIAN
MM21:    CJNE A,#0B0H,MM31
        MOV R1,#0BH
      CALL JIEDIAN
MM31:    CJNE A,#070H,XHPD2
         MOV R1,#0CH
         CALL JIEDIAN
  
         //檢測第四行
NO3:     MOV P3,#0F7H;
      MOV A,P3 
      ANL A,#0F0H
XHPD3:   CJNE A,#0F0H,OK3
         LJMP SCAN
OK3:     CALL DELAY0
      MOV A,P3
         ANL A,#0F0H
      CJNE A,#0F0H,MM40
   SJMP XHPD3
MM40:    CJNE A,#0E0H,MM41
      MOV R1,#0DH
   CALL  JIEDIAN
MM41:    CJNE A,#0D0H,MM42
      MOV R1,#0EH
   CALL JIEDIAN
MM42:    CJNE A,#0B0H,MM43
   MOV R1,#0FH
   CALL JIEDIAN
MM43:    CJNE A,#070H,XHPD3
   MOV R1,#10H
   CALL JIEDIAN 
   LJMP scan
JIEDIAN:
         DEC R1
         MOV  A,R1
         MOVC A,@A+DPTR
   CALL WRITE_DATE
   CALL DELAY
         SETB P2.6
      MOV  P0,A
      CLR  P2.6
      RET
 ////////////////////////////////////
//初始化液晶屏程序段
INTE: CLR P1.1      //讀寫選擇端口清零
   CLR P2.6      //關閉數碼管
   CLR P2.7
   MOV A,#0X38
   CALL WRITE_COM
   CALL DELAY
   MOV A,#0X0E
   CALL WRITE_COM
   CALL DELAY
   CALL DELAY
   MOV A,#0X06
   CALL WRITE_COM
   CALL DELAY
   CALL DELAY
   MOV A,#0X01
   CALL WRITE_COM
   CALL DELAY
   CALL DELAY
   MOV A,#0X80
   CALL WRITE_COM
   CALL DELAY0
   RET 
//10ms延時函數
DELAY:MOV R7,#0FFH
DELY1:MOV R6,#02AH
DELY2:NOP
      DJNZ R6,DELY2
   DJNZ R7,DELY1
   RET
//5ms延時函數
DELAY0:MOV R7,#0FEH
DELY10:MOV R6,#02FH
DELY20:NOP
      DJNZ R6,DELY2
   DJNZ R7,DELY1
   RET
//寫命令函數
WRITE_COM:
      MOV P0,A    //暫定A為數據傳輸寄存器
      CLR P1.0   //打開命令選擇端口
   CLR P1.1 //打開寫選擇端口
      CLR P2.5    //液晶使能端
   CALL DELAY  //10MS
   SETB P2.5   //液晶使能端
   CALL DELAY  //10MS
      CLR P2.5    //液晶使能端
      RET
// 寫數據函數
WRITE_DATE:
     MOV P0,A    //暫定A為數據傳輸寄存器
    SETB P1.0   //液晶數據/命令選擇端口
  CLR  P1.1   //讀寫選擇端口
     CLR  P2.5   //液晶使能端
  CALL DELAY  //10MS
  SETB P2.5   //液晶使能端
  CALL DELAY  //10MS
  CLR  P2.5   //液晶使能端
  RET
TABLE: DB 30H,31H,32H,33H,34H,35H,36H,37H,38H,39H,41H,42H,43H,44H,45H,46H,47H     
     END 
 

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