PIC timer1 interrupt never occurs

Question

Hello I am trying to use timer1 interrupt on PIC18F26K83. I use Micro C as compiler. So I set my timer for 30 ms and after that 30 ms, it is supposed to enter an interrupt and light the LED. But it never lights up the LED (never enters the interrupt/interrupt never occurs.). The code is:

 #define led LATA.RA2
void Clk_8Mhz(){
   //8 MHz clock
          //  OSCCON1 REGISTER
   NOSC2_BIT=1;
  NOSC1_BIT=1;
   NOSC0_BIT=0;//HF INTERNAL OSC
   //OSCFRQ REGISTER HFINTOSC FREQ. SELECTION


OSCCON1 =0b01100000; //HFINTOSC, Divider =1;
    FRQ3_BIT=0;
   FRQ2_BIT=0;
   FRQ1_BIT=1;
   FRQ0_BIT=1;    // 0011 :8MHz     //0100 = 16 Mhz
  }


  //Timer1
//Prescaler 1:1; TMR1 Preload = 5536; Actual Interrupt Time : 30 ms

void InitTimer1(){
  T1CON  = 0x01;
  TMR1IF_bit     = 0;
  TMR1H  = 0x15;
  TMR1L  = 0xA0;
  TMR1IE_bit     = 1;
  INTCON     = 0xC0;
}

void main (){
TRISA.B2=0;
led=0;
clk_8Mhz();
InitTimer1();
while(1){
 delay_ms(10);
}   }

void Interrupt(){
  if (TMR1IF_bit){
    TMR1IF_bit = 0;
    TMR1H    = 0x15;
    TMR1L    = 0xA0;
    led=1;
  }
}

What maybe the cause of this never occuring interrupt? Thanks beforehand.

Try the simulator and put a breakpoint in the ISR. what happens? — Mike

pm101 pm101 · Accepted Answer · 2019-05-13T13:13:03

Try setting MVECEN config bit to OFF (part of CONFIG2L) as your void Interrupt() code requires that, Also see Official statement regarding the K42 and K83 family issues (Mikro C)

Support for Interrupt Vector table for K42/K83 families was not implemented, only the legacy interrupt approach was supported.

PIC timer1 interrupt never occurs

1 Answers