Question

我遇到timer1外部时钟中断问题基本上我使用内部4mhz时钟和一个连接到T1OSI / T1OSO引脚的32khz晶体发生器。
问题是我无法从外部时钟产生中断。以下是我试图运行的代码：

 #define _XTAL_FREQ 4000000

// CONFIG
#pragma config FOSC = INTOSCIO  // Oscillator Selection bits (INTOSC oscillator: I/O function on RA6/OSC2/CLKOUT pin, I/O function on RA7/OSC1/CLKIN)
#pragma config WDTE = OFF       // Watchdog Timer Enable bit (WDT disabled)
#pragma config PWRTE = OFF      // Power-up Timer Enable bit (PWRT disabled)
#pragma config MCLRE = OFF      // RA5/MCLR/VPP Pin Function Select bit (RA5/MCLR/VPP pin function is digital input, MCLR internally tied to VDD)
#pragma config BOREN = OFF      // Brown-out Detect Enable bit (BOD disabled)
#pragma config LVP = OFF        // Low-Voltage Programming Enable bit (RB4/PGM pin has digital I/O function, HV on MCLR must be used for programming)
#pragma config CPD = OFF        // Data EE Memory Code Protection bit (Data memory code protection off)
#pragma config CP = OFF         // Flash Program Memory Code Protection bit (Code protection off)
#include <xc.h>

void interrupt isr(void){
    if(TMR1IF){
        RA0=!RA0;
    }
}
void main(void) {
    CMCON = 0x07; // comparators off
    TRISA = 0x00;
    RA0=1;
    __delay_ms(1000);
    RA0=0;
    TMR1CS=1;
    T1CONbits.nT1SYNC = 0
    TMR1IF = 0;        // Clear the timer1 interrupt flag
    TMR1H  = 224;
    TMR1L  = 0;
    TMR1IE = 1;
    TMR1ON = 1;
    T1CKPS1 = 1;
    INTCON = 0b11000000;

  while(1);
}

如果使用内部时钟，此代码有效，但如果配置为使用外部时间 - 则失败也许我做错了什么？谢谢你的任何想法。

Answer 1

好的，经过多次尝试，我已经设法让它发挥作用在32khz外部晶体上使用33pf电容代码：

#define _XTAL_FREQ 4000000

// CONFIG
#pragma config FOSC = INTOSCIO  // Oscillator Selection bits (INTOSC oscillator: I/O function on RA6/OSC2/CLKOUT pin, I/O function on RA7/OSC1/CLKIN)
#pragma config WDTE = OFF       // Watchdog Timer Enable bit (WDT disabled)
#pragma config PWRTE = OFF      // Power-up Timer Enable bit (PWRT disabled)
#pragma config MCLRE = OFF      // RA5/MCLR/VPP Pin Function Select bit (RA5/MCLR/VPP pin function is digital input, MCLR internally tied to VDD)
#pragma config BOREN = OFF      // Brown-out Detect Enable bit (BOD disabled)
#pragma config LVP = OFF        // Low-Voltage Programming Enable bit (RB4/PGM pin has digital I/O function, HV on MCLR must be used for programming)
#pragma config CPD = OFF        // Data EE Memory Code Protection bit (Data memory code protection off)
#pragma config CP = OFF         // Flash Program Memory Code Protection bit (Code protection off)

#include <xc.h>
void interrupt isr(void){
if(TMR1IF){
  TMR1ON = 0;
  RA0=~RA0;
  TMR1H = 0x80;
  TMR1L = 0x00;
  TMR1IF = 0;  
  TMR1ON = 1;
  }
}
void main(void) {
    CMCON = 0x07; // comparators off
    TRISA = 0x00;
    RA0=0;
    __delay_ms(5000);
    T1CKPS0 = 0;
    T1CKPS1 = 0;
    TMR1CS=1;
    TMR1H = 0x80;
    TMR1L = 0x00;
    T1OSCEN = 1;
    T1CONbits.nT1SYNC = 1;  
    TMR1IE = 1;
    GIE=1;
    PEIE=1; 
    TMR1ON = 1;
    while(1);
}

现在在RA0上获得正确的1s脉冲基本上它是预配置器和计数器寄存器值的严格配置在配置定时器后，您还需要使用TMR1ON。

PIC16F628外部timer1中断

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