Weird interrupt problem pic16f690

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Lipton2

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Hello guys!
I have been struggeling with this problem for hours now and i can't seem to get it fixed.
Maybe it is just is simple mistake, but i hope you can help me.
I am trying to make a simple interrupt with a PIC16F690 that blinks a LED every second.
As you can see i first declared all the INTCON en OPTION registers that were needed.
And since i have a default internal oscillator of 4Mhz I used a Fosc of 1 Mhz to calculate the count of overflows.

But when i program my device, instead of 1, all four LED's are on and they are not blinking.
What is wrong?

I hope you can help me!
Thanks in advance!

Oh btw, I use the XC8 compiler


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#include <htc.h>
#include <pic16f690.h>
 
 
    unsigned char counter=0;//Overflow counter
    //void interrupt ISR(void);
    void main()
    {
       //Setup Timer0
       OPTION_REGbits.PS0=1; //Prescaler is divide by 256
       OPTION_REGbits.PS1=1;
       OPTION_REGbits.PS0=1;
 
       OPTION_REGbits.PSA=0;      //Timer Clock Source is from Prescaler
 
       OPTION_REGbits.T0CS=0;     //Prescaler gets clock from FCPU (1MHz)
 
       INTCONbits.T0IE=1;   //Enable TIMER0 Interrupt
       INTCONbits.T0IF=0;
       INTCONbits.PEIE=1;     //Enable Peripheral Interrupt
       INTCONbits.GIE=1;      //Enable INTs globally
 
       TRISC=0;
      while(1)
      {
          
      };  
    }
 
    //Main Interrupt Service Routine (ISR)
    void interrupt ISR ()
    {
       //Check if it is TMR0 Overflow ISR
       if(INTCONbits.T0IE && INTCONbits.T0IF)
       {
           counter ++;
           if (counter == 15)
           {
 
         PORTCbits.RC0;
         counter = 0;
           }
         INTCONbits.T0IF=0;
      }
   }
 
Last edited by a moderator:

Thanks for your reply!
When I implement this in my code, all four LED´s (RC0-RC3) are on, but after a second or so, three (RC1-RC3) LED's turn off again. Isn't that very weird since I only gave an action to RC0? It seems like the program only goes through the interrupt once and then gets stuck in the main loop. How can I fix this?

Thanks!
 

Yes whatchdog timer was disabled, but i already fixed the problem I think!
I added an else statement to the if statement with the counter.
The LED now blinks every second!

Thanks for your help!

Code: 
    //Main Interrupt Service Routine (ISR)
    void interrupt ISR ()
    {
       //Check if it is TMR0 Overflow ISR
       if(INTCONbits.T0IF==1)
       {
           counter ++;
           if (counter == 15)
           {
                PORTC=0b00000001;
                counter = 0;
           }
           else PORTC =0;

         INTCONbits.T0IF=0;
      }
   }
 

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