;***********************************************************************
;              自收發(fā)光電檢測(cè).dt
;***********************************************************************
 PORT5    ==        0x05                ;定義端口5,6,7
 PORT6    ==        0x06
 PORT7    ==        0x07
;-----------------------------------------------------------------------
 IOCE     ==        0x0E                ;定義WDT控制寄存器IOCE
;-----------------------------------------------------------------------
 DLY1     ==        12                  ;定義延時(shí)置數(shù)單元DLY1，DLY2，DLY3,DLY4
 DLY2     ==        13
 DLY3     ==        14
 DLY4     ==        15        
 BUFFER   ==        16                  ;定義暫存器BUFFER，存放當(dāng)前輸出
;-----------------------------------------------------------------------
          ORG       0X00

 INIT:    MOV       A,@0X11             ;關(guān)閉看門狗功能
          IOW       IOCE
          MOV       A,@0XFF             ;設(shè)定PORT5全部為輸入
          IOW       PORT5              
          MOV       A,@0X00             ;設(shè)定PORT6、PORT7全部為輸出
          IOW       PORT6              
          IOW       PORT7              
          MOV       A,@0XFF             ;設(shè)置暫存器BUFFER初值，
          MOV       BUFFER,A
          MOV       PORT7,A             ;PORT7輸出指示LED全暗
          MOV       A,@0X00
          MOV       PORT6,A             ;PORT6輸出低電平，熄滅光電發(fā)射管
   
 GDCHECK: MOV       A,@0XFF         ;PORT6輸出高電平，點(diǎn)亮光電發(fā)射管
          MOV       PORT6,A
          CALL      DL10                ;發(fā)射時(shí)間維持5ms左右
          MOV       A,PORT5             ;從PORT5讀入光電接收管狀態(tài)
          AND       A,@0B00000111       ;屏蔽高5位，只保留3位
          XOR       A,@0XFF             ;光電接收管狀態(tài)值反向
          MOV       BUFFER,A            ;送暫存器BUFFER保存
          MOV       A,@0X00             ;PORT6輸出低電平，熄滅光電發(fā)射管
          MOV       PORT6,A

 DISPLAY: MOV       A,BUFFER            ;發(fā)光二極管顯示光電接收狀態(tài)值
          MOV       PORT7,A
          CALL      DELAY               ;采樣延時(shí)
          JMP       GDCHECK             ;繼續(xù)進(jìn)行自收發(fā)光電信號(hào)檢測(cè)
;-----------------------------------------------------------------------
 DELAY:   MOV       A,@1                ;延時(shí)，需要調(diào)整
          MOV       DLY3,A              ;1
 DEL:     MOV       A,@10               ;1*(DLY3)
          MOV       DLY2,A              ;1*(DLY3)
 INNER2   MOV       A,@250              ;1*(DLY3)*(DLY2)
          MOV       DLY1,A              ;1*(DLY3)*(DLY2)
 INNER1:  DJZ       DLY1                ;1*(DLY3)*(DLY2)*(DLY1)
          JMP       INNER1              ;1*(DLY3)*(DLY2)*(DLY1)
          DJZ       DLY2                ;1*(DLY3)*(DLY2)
          JMP       INNER2              ;1*(DLY3)*(DLY2)
          DJZ       DLY3                ;1*(DLY3)
          JMP       DEL                 ;1*(DLY3)
          RET                           ;延時(shí)返回
;-----------------------------------------------------------------------
 DL10:    MOV       A,2                 ;延時(shí)5ms左右，需要調(diào)整
          MOV       DLY4,A
 INNER3:  DJZ       DLY4
          JMP       INNER3
          RET       
          EOP