-----Original Message-----
From:   Scott Walsh [SMTP:Scott.WALSH@PLANTRONICS.COM]
Sent:   Wednesday, October 15, 1997 11:45 AM
To:     PICLIST@MITVMA.MIT.EDU
Subject:        Re[2]: (OT, sort of)Crystals oscillating at 3x marked freq

     I think Steve has probably identified your problem.

     You may have overlooked this parameter when specifiying the crystal
     that you are using, this is easy to do as it is not an intuitive thing
     to check for!

     AFAIK they call a third overtone XTAL an 'XT cut' and a fundamental
     mode XTAl an 'AT cut' ... anybody know what this is?

     BTW: Do you really need to have the accuracy and expense of a cystal,
     you will find a resonator cheaper although less accurate? But you can
     get people like Kyocera to build a resonator matched to your type of
     micro if you need greater accuracy!

     regards,
     SW.


______________________________ Reply Separator _________________________________
Subject: Re: (OT, sort of)Crystals oscillating at 3x marked freq
Author:  pic microcontroller discussion list <PICLIST@MITVMA.MIT.EDU> at
INTERNET
Date:    14/10/97 17:20


Crystal is not a third overtone type is it. If so try fundimental type this
may resolve the problem. Or could the value of bypass capacitors be marginal
check device data sheets for correct window of values Or use disamilar values
for bypass capacitors Or use ceramic resanator with inbuilt bypass capacitors
Or add series resistor 500R or so with the crystal.

Cant think of any more off hand but I am sure others will

Cheers Steve.....