单时钟完成多点分别计时的实现和应用

                   CJNE      A,#20,DE2
                        CLR       2CH.0                       
                        LCALL     OUT01
                        mov       50h,#00h
                        LJMP      DE2                       
DEAL2:                  JNB       2CH.1,DE3
                        INC       51H
                        MOV       A,51H
                        CJNE      A,#20,DE3                       
                        CLR 

      2CH.1                       
                &

《单时钟完成多点分别计时的实现和应用(第5页)》