抢答器.asm

基于51的抢答器

     ORG 0000H
     SETB P3.7
     MOV R0, #00H
     MOV A , #0FFH
     MOV P2 , A
L1:  MOV A , P1
     XRL  A , #0FFH
     JZ L1

L2:  MOV B , #02H
     DIV AB
     INC R0
     JNZ L2
     MOV DPTR,#TABLE
     MOV A,R0
     MOVC A , @A+DPTR
     MOV P2 ,A

     MOV R3 , #0FFH
SS:  CLR P3.7
     ACALL DELAY
     SETB P3.7
     ACALL DELAY
     DJNZ R3,SS
     
L4:  SJMP   L4

DELAY: MOV R1, #249
L3:  NOP
     NOP
     DJNZ R1, L3
     RET
TABLE: DB 0C0H,0F9H,0A4H,0B0H,99H,92H,82H,0F8H,80H,90H ;0-9
     END