[GreatFET] Will the Rhodadendron work now for this use case?

[Dillon Nichols]

Hey Kate,

Thanks for getting back to me, but you're right that it wasn't a protocol
issue. A mistake on the BOM changed the value of the bias resistor on the
USB PHY. Changing that to the correct value fixed it all.

Regards,
Dillon

On Thu, Dec 5, 2019 at 11:58 AM Kate Temkin <k at ktemkin.com> wrote:

> Hi, Dillon:
>
> Sorry for the delay -- I'm just getting back after a ton of travel. :)
>
> The Rhododendron hardware and software aren't stable/mature enough that
> I'd count on them for anything; and this point. They seem to be
> mostly-working over here, but they're not final hardware; and I haven't
> merged their software into GreatFET master. That said, theoretically the
> Rhododendron design that's on GitHub should be full-featured and could
> potentially be of use, if you're willing to devote some effort to working
> around potential bugs. :)
>
> Given the sound of your situation, though, I might suspect a signal
> integrity issue (or an issue with your D+/D- pull-downs) before suspecting
> a protocol error; in which case you might be better served with a fast
> oscilloscope than a board like Rhododendron.
>
> -- Kate
>
> On Thu, Nov 21, 2019 at 6:21 AM Dillon Nichols <ee.tinkerer at gmail.com>
> wrote:
>
>> My company makes a controller that uses Linux and has a USB port for
>> connecting USB drives. Our Rev AC board has no problems communicating to
>> all USB drives but our Rev AD board only communicates to certain USB
>> drives. The hardware team says there are no layout or BOM changes in this
>> circuit and the software team says the same software is running on both
>> hardware revisions and producing different behavior.
>>
>> I already have a GreatFET One and I'm wondering if the tools and hardware
>> for the Rhododendron are mature enough now that I can do some packet
>> analysis to track down the differences.
>>
>> Thanks in advance,
>> Dillon
>>
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>
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