Re: [Discuss-gnuradio] Sensitivity of USRP to power glitches

[Juha Vierinen]

I got a feeling of deja vu when reading your post. I haven't had any
problems for a long time now, but I never really found the true cause
of these problems. Still, in my mind I have hypothetically correlated
the following with protocol and  usb_reap_async errors:

1. Loose power supply connector
2. Bad USB cable
3. Using a non-USRP under-rated power supply
4. Old PC with a piece of shit USB controller
5. Fiddling around with daughterboards while USRP is live ;)
6. Static electricity during the winter

But as I said, I haven't seen these problems for a long time now. I
have managed to avoid causes 3, 4 and 5 during the last year or so,
but as I said, I don't really know the exact cause for the errors as
they were fairly sporadic.

juha

On Sat, Apr 11, 2009 at 17:33, Don Ward <address@hidden> wrote:
> Marcus Leech wrote:
>
>> Something I've noticed over the years with the USRP is that it seems
>> unusually sensitive to power glitches, even tiny ones. Maybe
>>  ground noise?
>>
>> For example, removing an RF connector while the USRP is powered up can
>> sometimes cause it to go into "Protocol Error -71" in and
>>  endless loop, and other things that might introduce small amounts of
>> ground noise.
>>
>> This morning, my wife started the vacuum cleaner outside my office.  The
>> USRP had been running entirely fine for 24 hours, and
>>  then as soon as the vacuum cleaner started (causing a small AC
>> glitch), the USRP crashed with "Protocol Error -71".
>
> I used to have problems when turning on a desk lamp or the computer
> speakers.  On Windows I was getting usb_reap_async errors.
>
>> Is this an USRP thing, or is it that the USB is rather noise sensitive,
>> and you normally don't see it because 99% of USB devices
>>  are powered from the PC, rather than independently, as the USRP is.
>
> My problem went away when I upgraded my computer.  This make me suspect that
> it is a USB problem.
>
> -- Don W.
>
>
>
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