Thanks Steve, I'll give this a go and see how I get on.

Cheers,
Mark

----- Original Message ----
From: Steve Sakoman <sakoman@gmail.com>
To: General mailing list for gumstix users. <gumstix-users@lists.sourceforge.net>
Sent: Wednesday, 2 April, 2008 4:30:36 PM
Subject: Re: [Gumstix-users] Noise radiating from Verdex board ii

Mark,

My guess is that the LCD signals are the culprit -- the LCD blanks
after a few minutes which would explain the disappearance of the
noise.

If you are using gumstix-oe,  you can disable the LCD by commenting
out the lcd MACHINE_FEATURES in
com.gumstix.collection/conf/machine/gumstix-custom-verdex.conf

Steve

On Wed, Apr 2, 2008 at 8:19 AM, Mark Ca <markjcarstairs@yahoo.co.uk> wrote:
>
>  Hi all, (apologies if this is the second time you've seen this message, I
>  don't think it went out the first time as I subscribed to the mailing list
>  AFTER I wrote the post!)
>
>  I'm having a problem with noise emissions from the Verdex XL6P motherboard
>  (paired with a breakout-GS board) and am trying to figure out what is
>  responsible so that I can disable or minimise it. I'm only using the I2C and
>  the battery power headers on the breakout board.
>
>  Bascially, whenever I power-on the board I get a slew of harmonics across a
>  wide band at approximately 17.3 MHz intervals which last for approximately
>  6-8 minutes before disappearing. The lowest frequency harmonic that I've
>  been able to detect has been 234 MHz but I have observed them at frequencies
>  up to and including 997 MHz (I believe these limits to be due to the
>  limitations of my measurement equipment rather than being representative of
>  band within which the harmonics occur).
>
>  Having been through the datasheet for the PXA270 and looked over the Verdex
>  documentation I have been unable to find anything that might be responsible
>  for these signals. Whatever it is, it is clearly something which is turned
>  off (perhaps to conserve power?) after several minutes and doesn't obviously
>  appear to affect the performance of the motherboard for my application (i.e.
>  after the harmonics have gone, everything still works fine).
>
>  If anyone has any thoughts on what this might be and how I can deal with it
>  (disabling the source is preferable to putting in physical screening) I'd be
>  very grateful to hear from you.
>
>  Many thanks,
>
>  M
>  --
>  View this message in context: http://www.nabble.com/Noise-radiating-from-Verdex-board-ii-tp16418465p16418465.html
>  Sent from the Gumstix mailing list archive at Nabble.com.
>
>
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