18F452, PWM and TMR0 problem

jimcbride · Joined: 05 Apr 2006 Posts: 23

Greetings,
I have some code that uses the TMR0 interrupt for a timing loop set to 50ms. I also use both hardware PWM units. Before entering main, PWMs are set to 500. OK there. The interrupt occurs 8 times and then performs some calculations. (8 times gives me 50ms) Anyway with the TMR0 interrupt disabled, the PWM gets set to 500 and stays there. When TMR0 is enabled, on the second time through, upon exiting the routine, both PWM signals get turned off. I have no idea why this is happening. I had very similar code running on a 16F877 with no problems.
Any ideas?
JIMc

PCM programmer · Joined: 06 Sep 2003 Posts: 21708

jimcbride · Joined: 05 Apr 2006 Posts: 23

Thanks, good advice. This is exaclty what I did after writing my post. And of course it worked fine so the problem was in my "large" code. I did fix it, although I am not entirely sure how. I just started stepping through it and commenting out the problem areas. At one point I noticed something odd that made no sence or had any use. I suspect the problem was an int declaration in the main( ) before the setup declarations. I have no idea why it was there. I have not looked at this code in over a year so who knows? Thanks for the help.