交通灯模拟实验程序

 GEWEI EQU 21H     ;个位数据
      SHIWEI EQU 23H    ;十位数据
      SCANLED EQU 25H
      SCANMODE EQU 26H
      RED EQU 28H       ;定义灯的缓冲区
      GREEN EQU 29H
      YELLOW EQU 32H
      NUMTIM EQU 33H
      LED EQU  34H


      ORG 000H
      JMP START
      ORG 0BH
      JMP TIMER0          ;定时器0中断入口
      ORG 100H
START: MOV  SP,#50H
       MOV  R0,#20H
       MOV  R5,#20
 CLR0: MOV  @R0,#00H
      INC R0
      DJNZ R5,CLR0
       MOV  TMOD,#01H       ;设置定时器
       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                  ;定时器部分，负责交通灯的及时和数码管动态扫描
         PUSH PSW
          MOV  TH0,#HIGH(65536-5000) ;重新赋初值
          MOV  TL0,#LOW(65536-5000)
         DJNZ R7,RET0
          MOV  R7,#200
           MOV    A,SCANMODE          ;调用扫描
           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
          MOV C  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    ;共阳字码表
END