From: Eric Blossom <address@hidden>
To: Lee Patton <address@hidden>
CC: Clark Pope <address@hidden>,Discuss gnuradio
Subject: Re: [Discuss-gnuradio] Embedded control of USRP
Date: Mon, 3 Apr 2006 11:20:34 -0700
On Mon, Apr 03, 2006 at 01:00:07PM -0400, Lee Patton wrote:
> Thanks for the reply, Clark. Basically, the project we're working on
> involves putting the USRP on a small UAV ("A" as in "aerial" not
> "autonomous"). So, weight and power consumption are key. The hydraxc
> looks very cool. However, I think we can go larger. And, for the first
> cut at a solution, we want to go for the simplest thing that works. It
> seems like the hydraxc might not be that. However, for a final design
> choice, it might work very nicely. In fact, it looks like it could be
> the solution, but it will take more time to get up and running than we
> have. I hope you will update the list as you make progress with the
> - Lee
The hydraxc looks cool, but I think it's going to be a bear to get GNU
Radio running on it. A couple of observations: no floating point (not
positive, but pretty sure about that), no MMU (otherwise they wouldn't
be running ucLinux).
Though I haven't played with a Virtex 4 with embedded PPC, I have
played with a Virtex II (V2P50) with 2x embedded PPCs and its
performance was underwhelming. Really small cache didn't help. After
spending quite a bit of time on it, I was unable to get the LWIP
TCP/IP stack to run at anything like wire speed using a 100Mbit PHY.
Couldn't even compute UDP checksums and keep up.
If you can afford the size/weight, I'd probably try one of the Pentium M
single board computers. Everything should just work on that platform.
Yes, they're a lot bigger than the hydraxc or gumstix, but they're
very likely to work right out of the box.
Also, unless you're a glutton for punishment, don't get the Celeron
version, spend the extra bucks and get the Pentium M.