T0作定时器汇编程序（查询法）

电路是：P0口接数码管的字型码笔段，P2口接数码管的数位选择端.

         SECOND EQU 30H
         TCOUNT EQU 31H
                ORG 00H
START: MOV SECOND,#00H
           MOV TCOUNT,#00H
           MOV TMOD,#01H
           MOV TH0,#(65536-50000)/256
           MOV TL0,#(65536-50000) MOD 256
           SETB TR0
DISP:   MOV A,SECOND
          MOV B,#10
          DIV A B
          MOV DPTR,#TABLE
          MOVC A,@A+DPTR
          MOV P0,A
          MOV A,B
          MOVC A,@A+DPTR
          MOV P2,A
WAIT: JNB TF0,WAIT
          CLR TF0
          MOV TH0,#(65536-5000)/256
          MOV TL0,#(65536-5000) MOD 256
          INC TCOUNT
          MOV A,TCOUNT
          CJNE A,#20,NEXT
          MOV TCOUNT,#00H
          INC SECOND
          MOV A,SECOND
          CJNE A,#60,NEXT
          MOV SECOND,#00H
NEX:   LJMP DISP
NEXT: LJMP WAIT
TABLE: DB 3FH,06H,5BH,4FH,66H,6DH,7DH,07H,7FH,6FH
          END