计数器用寄存器a.asm

我学单片机89C51时编的大部分程序都在里面

;用寄存器A保存计数值
        ORG 0000H
        SJMP START
        ORG 0030H
START:  MOV TMOD,#15H
        MOV TH1,#3CH
        MOV TL1,#0B0H
        MOV B,#14H
        SETB TR1
        MOV TH0,#0FFH
        MOV TL0,#0FFH
        SETB TR0

SERVE:  MOV TH1,#3CH
        MOV TL1,#0B0H
        CLR A
CHAXUN: JBC TF0,YICHU
        SJMP CHAXUN
YICHU:  CLR TF0
        INC A
        JBC TF1,CHAXUN
        DJNZ B,LOOP
        LJMP SERVE
LOOP:   MOV P1,A
        MOV B,#14H
        LJMP SERVE