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Mail Archives: geda-user/2011/11/07/15:40:52

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Subject: Re: [geda-user] PCIe card?
From: John Doty <jpd AT noqsi DOT com>
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Date: Mon, 7 Nov 2011 13:14:21 -0700
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On Nov 7, 2011, at 12:04 PM, Peter Clifton wrote:

> Has anyone here designed a PCI Express card (Using gEDA / PCB or
> otherwise?)
> 
> I see there are various options, such as FPGA with internal PHY /
> SerDes, FPGA + external PHY / SerDes, PCIe <-> local bus bridge (e.g.
> PLX's PEX 8311 chip).
> 
> 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 ;).

I haven't actually done it, but I did a feasibility study last year on this topic. I didn't win the implementation contract, so you may judge for yourself how much this is worth. 

I came to the conclusion that the FPGA with internal PHY/SerDes was the most sane alternative, mainly because if you make it external, you have to implement some other very difficult interface between the interface chip and the FPGA. Thus, the external interface doesn't actually solve your problem: it merely gives you another problem of comparable difficulty to solve.

It looked like a very daunting problem, regardless.

John Doty              Noqsi Aerospace, Ltd.
http://www.noqsi.com/
jpd AT noqsi DOT com



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