;交通燈模擬實驗程序
      GEWEI EQU 21H     ;個位數(shù)據
      SHIWEI EQU 23H    ;十位數(shù)據
      SCANLED EQU 25H
      SCANMODE EQU 26H
      RED EQU 28H       ;定義燈的緩沖區(qū)
      GREEN EQU 29H
      YELLOW EQU 32H
      NUMTIM EQU 33H
      LED EQU  34H


      ORG 000H
      JMP START
      ORG 0BH
      JMP TIMER0          ;定時器0中斷入口
      ORG 100H
START:MOV SP,#50H
      MOV R0,#20H
      MOV R5,#20
 CLR0:MOV @R0,#00H
      INC R0
      DJNZ R5,CLR0
      MOV TMOD,#01H       ;設置定時器
      MOV TH0,#HIGH(65536-5000)
      MOV TL0,#LOW(65536-5000)
      SETB TR0
      MOV IE,#10000010B    ;端口初始化
      MOV P0,#0FFH
      MOV P1,#0FFH
      MOV P2,#00H
      MOV P3,#0FFH
      MOV R3,#10
      MOV R2,#3
      MOV R1,#10
      MOV R7,#200
      MOV RED,#10
      MOV YELLOW,#3
      MOV GREEN,#10
      MOV NUMTIM,#10
      MOV LED,#0FFH
      AJMP $


      ;=============================================================

  TIMER0:PUSH ACC                  ;定時器部分，負責交通燈的及時和數(shù)碼管動態(tài)掃描
         PUSH PSW
         MOV TH0,#HIGH(65536-5000) ;重新賦初值
         MOV TL0,#LOW(65536-5000)
         DJNZ R7,RET0
         MOV R7,#200
          MOV   A,SCANMODE          ;調用掃描
          MOV   B,#4
          DIV   AB
          MOV   A,B
          RL    A
          MOV   DPTR,#TAB_SCAN
          JMP   @A+DPTR
TAB_SCAN: AJMP  RED_LIGHT
          AJMP  YEL_LIGHT
          AJMP  GRE_LIGHT
          AJMP  YEL_LIGHT
   RET0:  MOV  A,NUMTIM
          LCALL BIN_BCD
          MOV SHIWEI,A
          MOV GEWEI,B
          INC   SCANLED
          MOV   A,SCANLED
          MOV   B,#4
          DIV   AB
          MOV   A,B
          RL    A
          MOV   DPTR,#TAB_SCAN0
          JMP   @A+DPTR
TAB_SCAN0:AJMP  SCAN_L1
          AJMP  SCAN_L2
SCAN_L1: MOV   P2,#11111011B
         MOV   A,SHIWEI
         JMP   END_SCAN
SCAN_L2: MOV   P2,#11111101B
         MOV   A,GEWEI
         JMP   END_SCAN
END_SCAN:MOV   DPTR,#TABLE
         MOVC  A,@A+DPTR
         MOV   P0,A
         MOV   A,LED
         MOV   P1,A
         POP PSW
         POP ACC
         RETI

RED_LIGHT:MOV  LED,#11111100B
          MOV  NUMTIM,RED
          DEC  RED
          MOV  A,RED
          CJNE A,#0FFH,RET0
          MOV  RED,#10
          MOV  A,SCANMODE
          ADD  A,#01H
          MOV  SCANMODE,A
          JMP  RET0
YEL_LIGHT:MOV  LED,#11110011B
          MOV  NUMTIM,YELLOW
          DEC  YELLOW
          MOV  A,YELLOW
          CJNE A,#0FFH,RET0
          MOV  YELLOW,#3
          MOV  A,SCANMODE
          ADD  A,#01H
          MOV  SCANMODE,A
          JMP  RET0
GRE_LIGHT:MOV  LED,#11001111B
          MOV  NUMTIM,GREEN
          DEC  GREEN
          MOV  A,GREEN
          CJNE A,#0FFH,RET1
          MOV  GREEN,#10
          MOV  A,SCANMODE
          ADD  A,#01H
          MOV  SCANMODE,A
     RET1:JMP  RET0



 BIN_BCD:MOV  B,#10
         DIV  AB
         RET

 DELAY: MOV   R5,#02
    D1: MOV   R6,#200
    D2: MOV   R7,#200
        DJNZ  R7,$
        DJNZ  R6,D2
        DJNZ  R5,D1
        RET

TABLE:DB  0C0H,0F9H,0A4H,0B0H,99H,92H,82H,0F8H,80H,90H    ;共陽字碼表
END