Re: [Fx2lib-devel] Isochronous Streaming Using LibUSB from FPGA

[Xiaofan C. <xia...@gm...>]

On Fri, Jul 8, 2011 at 12:26 PM, Phil Behnke <phi...@gm...> wrote:
> Xiaofan,
>
> Thanks for the help.  I'm using Linux with a 2.6.38.2 custom compiled
> kernel.  In addition to the python application, I wrote a basic C program to
> do the same thing, but I still have the same problem.  Both the
> python-libusb1 app and the C program are using async transfers.  The maximum
> isoc data rate of 24MBps should hopefully be enough, since my data from the
> FPGA is at 19MBps.  I've been experimenting with the data rate from the FPGA
> to the FX2; I can slow the data rate way down to ~6MBps and everything works
> great, but any faster than that and it starts to fail. :-/

I see. It may not be that easy to achieve 24MB/s since your host side
code and the FPGA side logic need to be both good.

I suggest you to post questions to libusb mailing list. I remember
there are reports there about sustaining this 24MB/s isoc transfer
and 35MB-45MB/s bulk transfer speed using FX2.

> I'm not sure how to determine my USB chipset.

You can use lspci.
http://wiki.debian.org/HowToIdentifyADevice/PCI

> Chris - Thanks for your help.  I will check out FPGALink on your site as I
> am using the Nexys2 board.  (Great blog BTW; I've been using it as a
> reference over the past couple months while developing this project.)
>

I am not familiar with FPGA but I might try this in the future with
Spartan 3E (or 3Aor 3AN) Starterkit we have at work


-- 
Xiaofan