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Date: Tue, 8 Nov 2011 07:55:34 +1100
Message-ID: <CAKakQccfDYfPqi9qY0mxjgtoFC9x3WweOJBpd3rhzGuQ1C5P1Q@mail.gmail.com>
Subject: Re: [geda-user] PCIe card?
From: Stephen Ecob <stephen DOT ecob AT sioi DOT com DOT au>
To: geda-user AT delorie DOT com
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On Tue, Nov 8, 2011 at 6:04 AM, Peter Clifton <pcjc2 AT cam DOT ac DOT uk> wrote:
> Has anyone here designed a PCI Express card (Using gEDA / PCB or
> otherwise?)

I haven't, but earlier this year Darrell Harmon was using PCB to make
a PCIE x1 plug in card using an Altera Cyclone 4 GX FPGA:

http://archives.seul.org/geda/user/Mar-2011/msg00077.html

> I'm mainly curious as to what others have tried, and how tricky the
> process was. I'm looking at doing one, and am starting to think I might
> need to code support for differential traces in PCB ;).

That would be awesome!
I've given a little thought to it myself, but haven't had time to make
anything happen.
One idea I had for a quick start was to lay out and edit a PCB with
the differential pairs replaced by fat single traces of thickness (2 *
differential trace copper thickness + differential trace internal
spacing).  A fairly simple bit of code could later convert these from
fat single traces to differential pairs.

Best regards,
Stephen

-- 
Stephen Ecob
Silicon On Inspiration
Sydney Australia
www.sioi.com.au