PIC16F877A之定时TMR0

            tmr0     equ    01hpcl      equ    02hstatus   equ    03hoption_reg  equ  81hintcon    equ    0bhportc     equ    07htrisc     equ    87htmr0data  equ     15hcount     equ    20hrp0       equ    5horg      0000hnopgoto     mainorg      0005hmain  nopbsf      status,rp0movlw    00hmovwf    triscmovlw    07hmovwf    option_regbcf      status,rp0clrf     countloop1movf     count,0call     readmovwf    portcincf     count,1movlw    0fhandwf    count,1call     delaycall     delaycall     delaycall     delaycall     delaycall     delaycall     delaygoto      loop1delaybcf      intcon,2movlw    tmr0datamovwf    tmr0delay1btfss    intcon,2goto      delay1returnread   addwf     pcl,1retlw      b'10000000'retlw      b'11000000'  retlw      b'11100000'retlw      b'11110000'retlw      b'11111000'retlw      b'11111100'retlw      b'11111110'retlw      b'11111111'retlw      b'11111110'retlw      b'11111100'retlw      b'11111000'retlw      b'11110000'retlw      b'11100000'retlw      b'11000000'retlw      b'10000000'retlw      b'00000000'end

本程序利用的 16F877A的TMR0，具体如何设置请查找16F877C中的INTCON、OPTION_REG 、TMR0等相关特殊工作寄存器的功能说明。推荐李学海老师编写的PIC单片机实用教程。