0~99计数器的设计.asm

来自「基于Proteus的51系列单片机设计与仿真」· 汇编 代码 · 共 58 行

       ORG    00H
       JMP    START
       ORG    03H
       JMP    IN0
       ORG    13H
       JMP    IN1
START: MOV    IE,#85H
       MOV    IP,#04H
       MOV    TCON,#05H      
       MOV    DPTR,#TABLE
DISP:  MOV    A,R4
       MOV    B,#10
       DIV    AB
       MOV    20H,A
       MOV    21H,B         
DISP1: MOV    A,20H
       MOVC   A,@A+DPTR
       MOV    P1,A
       CLR    P2.0
       SETB   P2.1 
       LCALL  DELAY            
DISP2: MOV    A,21H     
       MOVC   A,@A+DPTR
       MOV    P1,A
       CLR    P2.1
       SETB   P2.0
       LCALL  DELAY
       AJMP    DISP
  IN0: MOV    A,R4
       CJNE   A,#99,ADD1
       AJMP   JP1
 ADD1: ADD    A,#01H
       MOV    R4,A
   JP1:NOP
       RETI
  IN1: MOV    A,R4
       CJNE   A,#00,SUBB1
       AJMP   JP2
 SUBB1:SUBB   A,#01H
       MOV    R4,A
   JP2:NOP
       RETI       
DELAY: MOV    R7,#05H
DELA:  MOV    R6,#28H
DEL:   MOV    R5,#8AH
       DJNZ   R5,$
       DJNZ   R6,DEL
       DJNZ   R7,DELA
       RET
TABLE:DB 0c0H,0f9H,0a4H,0b0H,99H
      DB 92H,82H,0f8H,80H,90H
      RET
      END