[sdiy] Xilinx 3E board comments

[Magnus Danielson]

From: "Jeff Farr" <moogah at gmail.com>
Subject: Re: [sdiy] Xilinx 3E board comments
Date: Fri, 9 Jun 2006 10:46:54 -0400
Message-ID: <78f89520606090746k51bdff2ax13d225bde94b7080 at mail.gmail.com>

> Just looking over the information at xilinx.  What is the difference
> between "System Gates" and "Logic Gates"?  Are system gates the ones
> used to "reprogram" the connections between the logic gates?

The problem is that the "gate" count that you can realize in a FPGA is not a
very strictly defined number. You can do overly happy estimates on available
gate count just as you can do overly pestimistic counts. The gate count measure
never was very good to start with. "System Gates" is an estimated gate count,
based on some semi-scientifical measures, but it is good enougth to get a basic
feel of the "size" of the FPGA. In real life you measure other resources such
as used LUTs, blockrams etc. It may seem a little strange in the beginning, but
you get used to it. By looking hard at the used resources for a design, and
figuring out ways to improve on it you can squeeze more out of the same chip of
silicon.

>  Also,
> the Ethernet connection is particularly interesting to me but the
> datasheet implies that it is really meant to be used with the
> microblaze, can the pico handle network processing?

Ethernet and microblaze is the combo you should consider, but the picoblaze is
not to consider for it. Sure, you can probably bang the things together, but
you will have to do alot more yourself. Really different types of applications.

> I'm dreaming up a simple sampler module that uses a network connection
> to talk with the computer..  I think the onboard ADC's could provide
> for an interesting "voltage controlled" sampler ;)

Ah well... ;O)

Cheers,
Magnus