t5.asm

《8051单片机彻底研究》一书的随书光盘

;PROGRAM NAME:T5.ASM
;TEST TIMER0 MODE 1:16 BIT COUNT UP
;
MS_100  EQU     30H
COUNT   EQU     9217    ;10mS FOR XTAL=11.0592MHz
CHECK_BIT REG   P3.2
;
        ORG     0
        MOV     R0,#00H
        DJNZ    R0,$    ;WAIT
        CLR     CHECK_BIT
        MOV     SP,#40H
        MOV     MS_100,#00H     ;CLEAR (MS_100)
;
        MOV     A,TMOD
        ANL     A,#11110000B
        CLR     ACC.3   ;GATE=0
        CLR     ACC.2   ;C/T=0
        CLR     ACC.1   ;TIMER0 M1=0
        SETB    ACC.0   ;TIMER0 M0=1
        MOV     TMOD,A
        MOV     TH0,#(65536-COUNT)/256
        MOV     TL0,#(65536-COUNT).MOD.256
        CLR     TF0     ;CLEAR TF0
        SETB    TR0
;
LOOP    JNB     TF0,LOOP  ;TF0=0
;TF0=1
OVER    CLR     TF0     ;CLEAR TF0
        MOV     TH0,#(65536-COUNT)/256
        MOV     TL0,#(65536-COUNT).MOD.256
        INC     MS_100          ;INCREMENT COUNT
        MOV     A,MS_100
        CJNE    A,#10,$NEXT
        CPL     CHECK_BIT ;P3.2 COMPLENENT
        MOV     MS_100,#00H     ;CLEAR COUNT
$NEXT   SJMP    LOOP
;