[Cryptech Tech] Novena dev-bridge board status

Fredrik Thulin fredrik at thulin.net
Wed Jun 24 13:00:57 UTC 2015


On Wednesday, June 24, 2015 03:41:46 PM Jacob wrote:
> On 6/24/2015 1:26 PM, Fredrik Thulin wrote:
> > On Wednesday, June 24, 2015 12:17:06 AM Павел Шатов wrote:
> > ...
> > 
> > Thanks! I'm ordering this board as it is now to put an end to the tweaking
> > =).
> > 
> > /Fredrik
> 
> There are still issues which I recommend to correct before ordering. Not
> "tweaking" but actually corrections. Again, the board might work without
> those corrections, but it might not.

Alea iacta est. It will be exciting to see if it works or not.

> I have not downloaded the latest design files from today, so if they are
> already fixed - all for the better.
> 
> 1. Crystals Y1 and Q1 (why different prefixes) each has 2 GND pads.
> These are not connected to the GND plane as they should, and neither the
> schematic shows such connections. The crystal body should be grounded to
> avoid parasitic capacitance to affect crystal stability and to minimize
> unwanted leakage.

Some crystal footprints have ground for the other two pads, and some do not - 
I haven't found any guidance as to why.

> 2. I know that there are issues with the AGND and GND in regard to the
> noise source, but it will take me a couple of hours or so to nail it
> down with a good explanation. I fire this mail to the list so Fredrik
> can hold off the release to production.

Please do take the time to write that down although the order is already in 
Shenzhen. Your comments will no doubt increase the likelihood of a working 
second board when the one I've already ordered shows up not working ;)

/Fredrik



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