y18.asm

这是时分秒即时钟的代码

             BUF EQU 79H
             ORG 0000H
             LJMP MAIN
             ORG 000BH
             AJMP INTRUPT
             ORG 0040H
TABLE:        DB 3FH,06H,5BH,4FH,66H,6DH,7DH,07H,7FH,6FH
              DB 77H,7CH,39H,5EH,79H,71H

DLY:          MOV R7,#02H
              MOV R6,#0FFH

DLYLOP:       DJNZ R6,DLYLOP
              DJNZ R7,DLYLOP
              RET
              ORG 0060H      
MAIN:         ;MOV BUF+0,#0     ;显示缓冲区
              ;MOV BUF+1,#1
              ;MOV BUF+2,#2
              ;MOV BUF+3,#3
              ;MOV BUF+4,#4
              ;MOV BUF+5,#5
              MOV 40H,#00H          ;秒地址
              MOV 41H,#00H             ;分地址
              MOV 42H,#00H              ;时地址
              MOV R0,#200H
              MOV R2,#50H

LOOP:         MOV TMOD,#00000010H ;定时器设置
              MOV TH0,#0CEH
              MOV TL0,#0CEH
              SETB EA
              SETB ET0
              SETB TR0
 
DISP:         MOV A,40H
              MOV B,#10
              DIV AB
              MOV 7AH,A
              MOV 79H,B
              MOV A,41H
              MOV B,#10
              DIV AB
              MOV 7CH,A
              MOV 7BH,B
              MOV A,42H
              MOV B,#10
              DIV AB
              MOV 7EH,A
              MOV 7DH,B

DISPLAY: ACALL DIR
        AJMP DISP

DIR:   MOV R1,#79H
       MOV R4,#01H
       MOV A,R4

BITS:  MOV DPTR,#8002H
       MOVX @DPTR,A

SEM:   MOV A,@R1
       MOV DPTR,#TABLE
       MOVC A,@A+DPTR

SM:    MOV DPTR,#8004H
       MOVX @DPTR,A
       ACALL DLY

DL:    INC R1
       MOV A,R4
       JB ACC.5,ID0
       RL A
       MOV R4,A
       AJMP BITS

ID0:  RET


INTRUPT:
          PUSH ACC
          PUSH PSW
          DEC R0
          CJNE R0,#00,EXT
          DEC R2
          MOV R0,#200
          CJNE R2,#00,EXT
          MOV R2,#50        
                   
          MOV A,40H
          INC A
          MOV 40H,A
          CJNE A,#60,EXT
          
          MOV 40H,#00H
          MOV A,41H
          INC A
          MOV 41H,A
          CJNE A,#60,EXT
          
          MOV 41H,#00H
          MOV A,42H
          INC A
          MOV 42H,A
          
          CJNE A,#24,EXT
          MOV 42H,#00H
          
  EXT:    POP PSW
          POP ACC
          RETI