rs232a.asm

关于单片机的一系列的设计程序

      NUM EQU 20H
      ORG 000H
      JMP START
      ORG 100H
      MOV NUM,#00H
START:MOV SCON,#50H
      MOV P0,#0FFH
      MOV P1,#0FFH
      MOV P2,#0FFH
      MOV P3,#0FFH
      mov   tmod,#20h
      mov   TH1,#0FDH    
      MOV   TL1,#0FDH
      SETB   TR1
LOOP: MOV DPTR,#TABLE
      MOV A,NUM
      MOVC A,@A+DPTR
      JZ  CLRA0
 RET1:INC NUM
      CLR TI
      MOV SBUF,A
     
      CLR RI
LOOP1:JBC RI,LOOP2
      JMP LOOP1
LOOP2:MOV A,SBUF
      MOV P1,A
      CALL DELAY
      JMP START

CLRA0:MOV NUM,#00H
      MOV A,NUM
      MOV DPTR,#TABLE
      MOVC A,@A+DPTR
      JMP RET1

DELAY:MOV R7,#50
   D1:MOV R6,#20
   D2:MOV R5,#248
      DJNZ R5,$
      DJNZ R6,D2
      DJNZ R7,D1
      RET

TABLE:DB 11111110B,11111101B,11111011B,11110111B
      DB 11101111B,11011111B,10111111B,01111111B
      DB 00000000B
      END