I sidestepped the oscillator problem when breadboarding a design by using a
canned oscillator instead of a crystal.  I have successfully run PIC's at
20MHz on one of those white breadboards that normally have too much
capacitance between pin rows to allow a crystal oscillator to run properly.

When the design is finished I replace the canned oscillator with a crystal
circuit.

HTH - Martin R. Green
elimar@bigfoot.com

----------
From:   Bob Blick[SMTP:bblick@TELIS.ORG]
Sent:   Thursday, September 11, 1997 2:55 PM
To:     PICLIST@mitvma.mit.edu
Subject:        '74A/JW startup woes

Hi,

On a perfboard prototype I'm working on, I'm having startup problems. Of
my bag of 16C74A/JW chips, only one or two of them like to work. If I put
in a real low-speed crystal instead of the 20MHz it's supposed to run at,
I can sometimes coax it to run.

Putting a scope on the crystal pins verifies that the oscillator is
running, but I suspect it's burping or slow getting up to speed or
something.

This perfboard nightmare has a ZIF socket on it, so the whole thing is
less than a favorable environment.

I recall seeing a thread with similar woes, but don't remember if anyone
came up with a solution.

Any takers? I've messed with caps, series resistors, etc, with no real
success.

Sure slows things down to only have 1 or 2 chips to work with.

Thanks in advance,

Bob