PIC Multiple Timer Interrupt Problem

[saneeshforu]

Haii all I have a problem related with Microc PIC IDE (v8.2)
I have 2 timer interrupts(tmr2,tmr1) in my program..like this..

void interrupt(){
  if (PIR1.TMR1IF) {
    PIR1.TMR1IF=0;
    cnt++ ;
    TMR1H = 0x80;
    TMR1L = 0x00;
  }
  else if(PIR1.TMR2IF)
  {
    PIR1.TMR2IF=0;
    cnt2++ ;
    TMR2  =   0;
  }     
}

But when Timer 2 Enables (PIE1.TMR2IE = 1) ,both of two interrupts(cnt and cnt2) get incremented ...why ?/

MY WHOLE PROGRAM IS THE BELOW ONE

unsigned short cnt;
unsigned short cnt2;


void interrupt(){
  
  if (PIR1.TMR1IF) {

    PIR1.TMR1IF=0;
    cnt++ ;
    TMR1H = 0x80;
    TMR1L = 0x00;

  }

  else if(PIR1.TMR2IF)

  {
    PIR1.TMR2IF=0;
    cnt2++ ;
    TMR2  =   0;

  }

}

void main()
{
  ANSEL  = 0;            // Configure AN pins as digital I/O
  ANSELH = 0;
  TRISB = 0xFF;          // set PORTB to be input
  TRISE = 0;
  TRISD = 0;             // set PORTD to be output
  PORTD = 0x00;
  PORTE=0X00;          // initialize PORTD
           

  T1CON = 1;
  T2CON = 0xFF;               // Timer2 settings
  TMR2  =   0;                // Initialize Timer2 register
  TMR1H = 0x80;               // Initialize Timer1 register
  TMR1L = 0x00;
  INTCON = 0xC0;
  PIE1.TMR2IE = 1;
  PIE1.TMR1IE  = 0;
  PIR1.TMR1IF=0;
  cnt=0;
  cnt2 = 0;
  PIR1.TMR2IF=0;

  for(;;)
  {

    if(cnt==61)

    {
      PORTE=~PORTE;
      cnt=0;
    }
     
    else  if (cnt2==160)
    {
      PIE1.TMR2IE = 0;
      PIE1.TMR1IE  = 1;
      cnt2=0;
      cnt=0;

      PORTD=~PORTD;
    }
     
  }
}

 

[KrisBlueNZ]

Have you forgotten to set the PR2 register?

What PIC device are you using?

 

[kpatz]

Based on your T2CON and T1CON settings, timer1 is overflowing before timer2, so its interrupt flag is set before your timer2 interrupt fires.

Disabling the interrupt (TMR1IE) only stops the interrupt from occurring, it doesn't stop the TMR1IF interrupt flag from getting set.

Use this to get around it:

if (PIR1.TMR1IF) {
    PIR1.TMR1IF=0;
    if (PIE1.TMR1IE) {
      cnt++ ;
      TMR1H = 0x80;
      TMR1L = 0x00;
   }
  }

 

[saneeshforu]

thanks for your consideration and time ...actually i forget to use TMR1ON in TCON reg..now it is working