PIC16F628外部定时器1中断

Question

我遇到了 timer1 外部时钟中断的问题。
基本上我使用的是内部 4mhz 时钟和连接到 T1OSI/T1OSO 引脚的 32khz crystal 发生器。
问题是我无法从外部时钟产生中断。下面是我正在尝试的代码运行:

 #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钟，则失败。
也许我做错了什么？谢谢你的任何想法。

Answer 1

好的，经过更多尝试，我已经成功了。
在 32khz 外部使用 33pf 电容器 crystal.
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。
基本上是预分频器和计数器寄存器值配置不当。
另外你需要在配置定时器后使用TMR1ON。

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