WDT question... debugging

[s_mack]

Crap, I posted this a couple days ago and I was wondering why nobody was answering... now I see my post must not have taken :(


Anyway. I have a WDT issure.

PIC 18F4480

When I set WDT_OFF (first line of main()) then everything works good. Setting it to WDT_ON and my device doesn't work - it appears to "stall". I presume then that this means the watchdog isn't getting reset in time. I do have restart_wdt() in my main() code and it was working before I made some changes to my code. So obviously the changes I made are slowing down the system to the point that the WDT can't be reset fast enough.

So that's my issue... is there a way to "time audit" to figure out what routine(s) is/are taking too long?

If it helps, here's the top of my header file:

[PCM programmer]

To measure the time required for a block of code, you can use the
MPLAB Simulator's Stopwatch feature. This thread has instructions on
how to use it:
http://www.ccsinfo.com/forum/viewtopic.php?t=38351

You can also set an i/o pin high at the start of a routine and low at the
end, and use an oscilloscope or a logic analyzer to see the pulse length,
and thus find the length of the routine.

On a more global scale, you could output a pulse just after the line that
calls restart_wdt() in your program. Then use a scope or logic analyzer
to see the time between pulses. (Or, just toggle an i/o pin at that line).
This assumes you have only one line that calls restart_wdt().

[s_mack]

Thanks for the link. I'll check out the simulator.