[SOLVED] Timer1 in 16F1938 with wrong interrupt time

[Rtk89]

A would like to generate interrupts every 250ms with Timer1, but I get interrupts with more than 1 sec using the code below (I am writing it in MikroC PRO for PIC).
I set frequency to 8MHz with internal oscillator.
What is the problem?
Thank you for helping.

void InitTimer1(){
  T1CON	 = 0x31;
  TMR1IF_bit	 = 0;
  TMR1H	 = 0x0B;
  TMR1L	 = 0xDC;
  TMR1IE_bit	 = 1;
  INTCON	 = 0xC0;
}


void Interrupt(){
  if (TMR1IF_bit){
    TMR1H	 = 0x0B;
    TMR1L	 = 0xDC;
    PORTC.F0 = ~PORTC.F0;  
    TMR1IF_bit = 0;
  }
}


void main() {
TRISA = 1;
TRISB = 0;
TRISC = 0;

ANSELA = 0;
ANSELB = 1;

C1ON_bit = 0;      // Disable comparators
C2ON_bit = 0;
ADON_bit     = 1;  // ADC on
ADNREF_bit   = 0;  // -VREF = VSS
ADPREF0_bit  = 1;  //VREF+ is connected to internal Fixed Voltage Reference (FVR) module(1)
ADPREF1_bit  = 1;


ADC_Init();        // Initialize ADC module with default settings

InitTimer1();
  
do{

}while(1);

 

[xenos]

This mC can run with INTOSC from 32KHz to 32MHz.
You have not configured OSCCON, so you run (by default) at 500KHz.
Try to add

OSCCON = 0x72; //OSC=1110 = 8MHz

during init of IC (before setting timer1).

 

[Rtk89]

Thank you for your help. I will try it.
Otherwise, this screen in MikroC doesn't set the frequency of the mC ?

 

[xenos]

No. This is just for the configuration word. It forces mC to use Internal Oscillator. But what frequency to use?

 

[Rtk89]

I thought that I can set frequency with the "MCU Clock Frequency[MHz]" field in the right part of the window.
Thank you very much for helping.