gnupic: Re: [gnupic] help - weird intermittent resets
Subject:
Re: [gnupic] help - weird intermittent resets
From:
Leo Britto ####@####.####
Date:
30 Jul 2005 15:42:48 +0100
Message-Id: <42EBD973.3040402@yahoo.com.br>
I am not reading everything regarding this thread but i notice you
turned on the watch dog timer... do you remember to reset it every once
in awhile? It will reset your system if it is not reset periodically.
Hope this is the problem because layout problems shouldnt cause you that
kind of thing as i am aware of.
Good luck and keep us posted.
Dan Andersson wrote:
> As my old teacher in electronics always said...
>
> Have you measured the circuit?
>
> No, not with a DVM! With an oscilloscope!
>
> You cannot claim a rock solid 4.85V from the supply until you measured
> it with an oscilloscope.
>
> Cheers
>
> Dan
>
>
> On Sat, 2005-07-30 at 14:13 +1200, David McNab wrote:
>
>>Hi,
>>
>>I'm getting a weird and frustrating problem with a pic18f252 that
>>intermittently resets itself.
>>
>>I've reduced my test program to the bare essentials - pseudo-code is:
>>
>> - clear trisc.0
>> - while true
>> - reset portc.0 # turn on piezo buzzer
>> - wait 1ms # long enough to click buzzer
>> - set portc.0 # turn off buzzer
>> - wait 249ms
>>
>>Config:
>> - wdt and bor are on
>> - 20 MHz crystal, with 18pF caps to ground
>>
>>Observations:
>> - pic resets at random times, varying between 1s and 20s
>> - pic resets much less often when I disconnect the
>> max232-based tty interface
>> - pic resets less often with much smaller progs (eg, the above
>> test prog written in c and compiled under ccs, as opposed to written
>> in forth and bloated out to 4k by the vm and support code)
>> - power supply is delivering rock-solid 4.85 volts
>> - i cannot reproduce this resetting when running the prog via gpsim
>>
>>Thoughts:
>> - crystal is dodgy, locking up
>> - pic is affected by ambient electrical noise
>>
>>Any ideas on cause, and fix/workaround?
>>
>
>
>
>
>
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