AVR- Interrupt flag not getting cleared up

[sanka1p]

Hi All,

I am using Atmega1608 and using its internal AC to generate an INT on its positive edge. My system work as required for a second or two, but then suddenly my AC INT flag never gets cleared. I haven't faced this issue before, I am attacghing my AC init code and ISR for it. Please take a look at it. My IDE is IAR for AVR.

Code: [Select]

void analog_comparator_init()
{
 VREF.CTRLA = VREF_AC0REFSEL_2V5_gc;   /* Voltage reference at 2.5V */
 VREF.CTRLB = VREF_AC0REFEN_bm;        /* AC0 DACREF reference enable: enabled */
 
 AC0.DACREF = 255;                   /* Set DAC voltage reference */
 AC0.MUXCTRLA = AC_MUXPOS_PIN0_gc;
 AC0.MUXCTRLA |= AC_MUXNEG_DACREF_gc;
 
 AC0.INTCTRL = AC_CMP_bm;
 
 AC0.CTRLA = AC_OUTEN_bm | AC_INTMODE_POSEDGE_gc | AC_ENABLE_bm ;
}
 
#pragma vector = AC0_AC_vect
__interrupt void AC_INT()
{ 
 
 AC0.STATUS= AC_CMP_bm;
 PORTA.OUTSET = PIN5_bm;
   
       if (TCB0.CNT > 150)
       {
         EVSYS.STROBE = EVSYS_STROBE0_EV_STROBE_CH1_gc;
       }
 
  PORTA.OUTCLR = PIN5_bm;
}

[mikerj]

You don't have any hysteresis configured, perhaps you are seeing the interrupt being constantly raised due to noise when the input voltages of the comparator are very close?