Brian,

There is 470uF, 25V cap very close to the 7805 (pic board), there is on =
cap (smd, I don't know the value) very close to the chip between vss and =
vdd and another smd cap very close to the chip also between the other =
vss and vdd.  There is also a 100uF, 16V cap between the one of the smd =
caps and the 7805.

So I am guessing what you have suggested is already done.  Also, when =
the unit is near a pump/motor, the keyboard seem to get messed up too.  =
As if somebody is clicking the buttons, but no one is.  I also tried to =
fix this in the software, by reading the button 10-20 times within =
certain amount of time to make sure if it is actually a button press.

regards,

Omer

-----Original Message-----
From: pic microcontroller discussion list =
[mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of Brian Clewer
Sent: Monday, July 14, 2003 8:52 PM
To: PICLIST@MITVMA.MIT.EDU
Subject: Re: [PIC]: WDT was C compiler choice ?


=D6mer Yalhi wrote:

> I happen to be an engineer (computer eng.) myself.  However, without
> enough experience with electronics.  That is why I had an electronics
> engineer design the board.  Now the board fails at times, and he tells
> me to fix it with WDT and that is what I have been trying to solve.

=D6mer, if you are able, try soldering a 100uf cap and a 100nf cap to =
the PIC
board accross the power supply less than 1 inch from the PIC.  I would =
bet
this would fix your problem.  The 100uf cap keeps the supply up when a =
heavy
demand of current is made (or by fast switching of the outputs) and the
0.1uf should ground most of the high frequency ripple.

Brian.

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