18f6525 timer3 interrupt problem

[jg]

Using PCH v 3.230.

Code below.

Explanation: Timer 2 provides the period (1Khz)for the software PWM. I need two seperate duty cycles. Timer 4 provides one and timer 3 provides the other one. Timer 4 is adjustable (30-99% of 1Khz) depending on a setting, this part works flawlessly. My problem is with timer 3, I'm wanting a fixed 50% duty cylce of the 1Khz. Using the o-scope on a pin it works "most of the time", but a lot of the time it is a 2% duty cylce instead of the set 50%.

I'm not using either compare or capture, what else could cause the timer1 to interrupt before it rolls over?

void timer2_int(void)
{
set_timer4(0);
PIR3 &= 0xF7; // clear interrupt for Timer
enable_interrupts(int_timer4);

if(PWM_dutyflag)
output_high(regulator);
else
output_low(regulator);

//PMW for dump valve
output_high(SOLSTART);
set_timer3(64900);
enable_interrupts(int_timer3);
}

#int_timer4
void timer4_int(void)
{
disable_interrupts(int_timer4);
output_low(regulator);
}

#INT_TIMER3
void timer3_int(void)
{
disable_interrupts(int_timer3);
if(!(input(compsw)))
output_low(SOLSTART);
}

Thanks for the time.

[PCM programmer]

[jg]

timer1 was a typo, should read timer3

[PCM programmer]

I noticed two things:

1. You clear the interrupt flag for Timer4 before you enable it,
but you don't do this for Timer3.

2. You read a switch inside the Timer3 isr. Switches can bounce.

[jg]

not a switch, but either way wouldn't cause what I am seeing.

I'll try clearing timer 3.

Thanks for the time.