PIC12F675 Timer1问题

我配置timer1以允许我的代码每20mS运行一次有困难……我的主程序执行它的事情，然后检查PIR1、TMR1IF，等待Timer1到期……；按照Timer1所确定的，在20mS时间范围内循环；通过打开main_.bsf GPIO、PWM_BIT上的PWM输出开始；输出在bcf PIR1，TMR1IF；清除定时器1溢出标志bsf T1CON，TMR1ON；定时器使能调用a_子例程调用另一个调用和_a_.；等待20msframewait_20m***tfss PIR1，TMR1IF的结束；等待定时器1溢出标志goto wait_20msgoto main_loopI正在使用PICs内部振荡器，因此我想我可以设置定时器配置错误...;设置定时器1控制寄存器movlw b'00001000';u0xxxxxx:TMR1GE OFF: ux00xxxx:Prescaler 1:1;uxxx1xx:Enable LP振荡器;uxxxxxxxx1xx:Do Not Synchronise to External Clock;uxxxxxxxxxx0x:设置内部时钟(Fosc/4);uxxxxxxxxxxx0:Do No No Not启用Timer1 movwf T1CON;写到T1CON;设置Timer1 Timing Registers movlw 0x17;将定时器设置为20ms movwf TMR1H movlw 0xe4 movwf TMR1LI尚未确定TMR1H和TMR1L值应该是什么，虽然我只是将其连接到频率计上使其点亮，但我所能得到的是15Hz，即使我改变了这些价值，我也必须做一些愚蠢的事情。任何想法！



      以下为原文

    I'm having trouble configuring Timer1 to allow my code to run every 20mS...
My main program does its thing then inspects PIR1,TMR1IF to wait for Timer1 to expire.....

; This loops at a 20mS time-frame, as determined by Timer1
; Start by turning the PWM output on
            
main_loop   
    bsf    GPIO,PWM_BIT        ;Output on
    bcf    PIR1,TMR1IF        ;Clear timer 1 overflow flag
    bsf    T1CON,TMR1ON        ;Timer enable

    call    a_subroutine
    call    another
    call    and_a_third

; Wait for end of 20ms frame

wait_20ms   
    btfss    PIR1,TMR1IF        ;Wait timer 1 overflow flag
    goto    wait_20ms

    goto    main_loop

I'm using the PICs internal oscillator, so I think I may have the Timer configuration wrong....

;Set Timer 1 Control Register

    movlw    b'00001000'        ;u0xxxxxx : TMR1GE OFF :
                                           ;ux00xxxx : Prescaler 1:1
                                           ;uxxx1xxx : Enable LP Oscillator
                                           ;uxxxx1xx : Do Not Synchronise to External Clock
                                           ;uxxxxx0x : Set internal clock (Fosc/4)
                                           ;uxxxxxx0 : Do Not Enable Timer1
    movwf    T1CON                ;write to T1CON

;Set Timer 1 Timing Registers

    movlw    0x17                   ;Set timer to 20ms
    movwf    TMR1H
    movlw    0xe4
    movwf    TMR1L


I have yet to determine what TMR1H and TMR1L values should be, thought I'd just hook it up to a frequency meter to get it spot-on, but all I can get is 15Hz, even when I change those values...

I must be doing something daft.... any ideas !