piclist 2002\08\06\040207a >
Thread: [EE]: Unstable circuit
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face BY : Mike Pink email (remove spam text)



You don't mention -mclr

Pull it up to Vdd with a 4k7 resistor

Mike



----- Original Message -----
From: "Fredrik Axtelius" <EraseMEfredrik.axteliusspamBeGonespam.....TELIA.COM>
To: <EraseMEPICLIST@spam@spamspamBeGoneMITVMA.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.
{Quote hidden}

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