Olin Lathrop wrote:

> One of my earlier PIC projects wasn't working.  As I reached over to put =
a
> scope probe on some pin, it started working.  Then I noticed that just
> moving my hand nearby made it work.  I thought maybe MCLR was floating an=
d
> the capacitance to my hand was making it flip, but MCLR was driven well
> enough.  It finally turned out to be that moving the hand between the PIC
> and the nearby window made it work because that reduced the light hitting
> the die of the JW part.  Since then I always put stickers over the window=
s,
> even if just for short testing.
>=20

This was a silicon bug in some parts. Some of the registers reset=20
incorrectly on startup when the window was not covered. In general=20
windowed parts should always be covered to avoid light sensitivity=20
causing random logic errors.

Regards,


w..

--
Walter Banks
Byte Craft Limited
http://www.bytecraft.com
--=20
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