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Unable to get external interrupts in pic18f452

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Naumanpak

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Experts,

I am not getting interrupts working.

From the data sheet, I have set out the values for bits but doesnt work. I can use it a a simple input port but not with interrupts. kindly help me out.

here is a simple test code I wrote,


Code: 
 int count=0;

void interrupt()	// Interrupt function definition
    {
       INTCON.INT0IF=0;
        count++;
       }

void main()
     {


      TRISB = 0;
      INTCON.INT0IF=0;
      INTCON.INT0IE=1;
      PORTB = 0;

      Lcd_Init(&PORTB);         // Initialize LCD connected to PORTB
      Lcd_Cmd(Lcd_CLEAR);       // Clear display
      Lcd_Cmd(Lcd_CURSOR_OFF);  // Turn cursor off

     Lcd_Out(1, 1, "Waiting..");
      while(count==0);
      
       Lcd_Out(1, 1, "interrupt!!1");
      
 }

thanks
 

Naumanpak,you seem to be thinking of interrupts as simple function calls, its not the way to go my friend ... I am assuming this is C18 compiler ? ... If thats true, read the user guide (2.9.2.3 Interrupt vectors) ... also fix the comon mistake of I/O digital config (If you havent already), and I do not see any input assignment in your code, you have to configure your pin INT0 to digital input ...
 

    N

    Naumanpak

    Points: 2
    Helpful Answer Positive Rating
Hi,
I'm assuming this is mikroC compiler.
In that case, first, you need to set the INT0 pin as digital input:

Assuming this is 16F877A, you need to set RB0 as input as :


Code: 
 int count=0;

void interrupt()   // Interrupt function definition
    {
       INTCON.INT0IF=0;
        count++;
       }

void main()
     {


      TRISB = 1;
      INTCON.INT0IF=0;
      INTCON.INT0IE=1;
      PORTB = 0;

      Lcd_Init(&PORTB);         // Initialize LCD connected to PORTB
      Lcd_Cmd(Lcd_CLEAR);       // Clear display
      Lcd_Cmd(Lcd_CURSOR_OFF);  // Turn cursor off

     Lcd_Out(1, 1, "Waiting..");
      while(count==0);
     
       Lcd_Out(1, 1, "interrupt!!1");
       while (1);
     
 }

Hope this helps.
Tahmid.
 

    N

    Naumanpak

    Points: 2
    Helpful Answer Positive Rating
Hi, thanks Tahmid.

RBO is now declared as digital input, as it should be. But still no results....

If I just use condition 'if(RB0==1)' in this code, it works..

Perhaps I am unable to initialize interrupts, even if i set the flag bit high manually, i dont get interrupts.

I am using mikroc and pic18f452.
Kindly kindly do suggest.

thanks

Added after 1 minutes:

thanks korena, I am using mikroc compiler.

Can you suggest, please.


thanks

Added after 30 minutes:

Hey thanks ALL!!!

Actually I didnt enable global interrupts.


thanks
 

pull down rb0 with 10k resistor solved my problem with above code
 

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