> > I have tried to put +5 on either and both of the VDD pins,
> same thing with
> the VSS.

+5 to both Vdd.  Vss to Ground (not +5).  Typo?

I had a similar problem and it was the /MCLR was not pulled high like Mike
indicates below.  Same "touch it and it resets" effect.

-Derek


> -----Original Message-----
> From: Mike Pink [mailto:mjpink@KINGSTAG.COM]
> Sent: Tuesday, August 06, 2002 2:21 AM
> To: PICLIST@MITVMA.MIT.EDU
> Subject: Re: [PIC][EE]: Unstable circuit
>
>
> You don't mention -mclr
>
> Pull it up to Vdd with a 4k7 resistor
>
> Mike
>
>
>
> ----- Original Message -----
> From: "Fredrik Axtelius" <fredrik.axtelius@TELIA.COM>
> To: <PICLIST@MITVMA.MIT.EDU>
> Sent: Monday, August 05, 2002 11:59 PM
> Subject: [PIC][EE]: Unstable circuit
>
>
> > Hi!!
> >
> > I have a PIC16F877 circuit and im having big problems to
> get it stable.
> >
> > Problem:
> > It will only run for a short time and only if im touching
> GND with one
> hand.
> > When I touch GND with one hand all I have to do is wave the
> other hand a
> few inces from the circuit to get it to reset, now if I keep that hand
> really still I can watch it run for like 5-10 secs before it
> lock ups (not
> resets).
> >
> > Hardware:
> > All I have is a 4Mhz 16f877, osc caps are 27p
> > One LED on RC4 with a resistor to GND.
> > Max232 with all the caps on RC6 and 7. The other end of the
> max232 is
> connected to my com1.
> > A reset button with a 10k pullup resistor.
> > All my cables are short and nicely layedout and my
> powersupply delivers a
> stable +5v.
> >
> > What I have tried so far:
> > I have tried to put +5 on either and both of the VDD pins,
> same thing with
> the VSS.
> > I have put caps between none, either or both of the VSS/VDD pins.
> > I disconnected the Max232 on rc6 and rc7, still the same problem.
> > I tried a 16f874 at both 20 and 4Mhz, same thing.
> >
> > Help me!
> > /Fredrik
> >
> > --
> > http://www.piclist.com hint: PICList Posts must start with
> ONE topic:
> > [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other
> [BUY]:,[AD]: ->Ads
> >
> >
>
> --
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> (like ads or off topics) for you. See http://www.piclist.com/#topics
>
>

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