With the JW part - I've seen reports that not covering the window can cause
problems.
Also - is the clock working OK - if this is unreliable then it can cause
problems.
Brownout detector problem - DC voltage problem?,
And I had a problem with a solder short on the reset line - most confusing
- when the PIC perfomed its main action it suddenly reset itself!

Richard P

"Andrew E. Kalman" wrote:

> Hi All.
>
> For some time now I've been unable to resolve a PIC18C452 problem, so
> I thought I'd ask the list for help.
>
> I've created an application with MPLAB and MPLAB-C18 that basically
> uses PORTB for some visuals and a single interrupt (TMR2). It works
> great in the (albeit sloooooow) MPLAB-SIM simulator. All the timing
> is fine, PORTB is changing as I expect, etc.
>
> HOWEVER, when I program a JW windowed part and put it on a PICDEM-2
> board, only part of the program works. The interrupt is happening at
> the right rate (I have it toggle an LED on PORTB) down to the
> millisecond, and a counter that is being incremented "in the main
> loop" is reflected properly on some more LEDs hanging off PORTB, but
> the rest of the program just ain't happening.
>
> My best guess is that there is some issue w/regard to memory access
> that is not the same between the simulator and the actual chip, and
> therefore the rest of the code is "silent."
>
> I've checked the errata, and there's nothing suspicious there.  I've
> disabled all the options (e.g. Watchdog timer) when programming the
> part through a PICSTART Plus. I've even sucked the code back from the
> chip into MPLAB and simulated it, and it works fine in the simulator.
>
> Any ideas on why it works in the simulator and not in the actual part?
>
> Thanks,
> --
>
>   ______________________________________
>    Andrew E. Kalman, Ph.D.   aek@pumpkininc.com
>
> --
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  |  __O    Thomas C. Sefranek  tcs@cmcorp.com
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