Comments on: FX2 CyStream throughput test with SDCC and fx2lib

By: Kurt

Kurt — Mon, 14 Feb 2011 09:31:28 +0000

look great. thanks your sharing.

By: Richard

Richard — Fri, 01 Oct 2010 06:27:55 +0000

I’ve been out of the country and just got back. Thanx for the pointers and I’ll check out nitro and see if it can help.

Also, I went to ubixum.com. Am I missing something as I do not see any products, etc.?

I joined the mailing list.

By: Dennis

Dennis — Wed, 08 Sep 2010 12:07:49 +0000

No problem. The driver included is a bit of a sample driver. It works for testing but probably isn’t going to get anyone anywhere too fast on a real project. Ubixum released a driver that works on both windows and Linux:

http://github.com/ubixum/nitro
Also, a couple firmwares for various projects we did.
http://github.com/ubixum

In addition to the basic USB connectivity, that firmware provides a convenient way to map hardware addresses to a human readable terminal/register structure that you can get and set values from. We then built our software on top of that.

Anyway, Best way to contribute changes is to create a github repo with a fork of fx2lib and then commit the changes and submit a change request that I can pull.

Also, consider joining the fx2lib mailing list

Thanks for your interest!

By: Richard

Richard — Sun, 05 Sep 2010 06:19:53 +0000

Sorry for the above, I noticed the indentation didn’t stay.

By: Richard

Richard — Sun, 05 Sep 2010 06:18:44 +0000

I think I have the latest copy of fx2lib as I used github to download just a few days ago. I had to fix the fx2/cpp files to work under Ubuntu 10.04 as follows:

void
fx2::open(int vid, int pid, int idx) {
libusb_device **list;
int devices = libusb_get_device_list(libusb_ctx, &list);
int cur_idx = 0;
for (int i = 0; i < devices; ++i) {
libusb_device_descriptor dscr;
if (!libusb_get_device_descriptor(list[i], &dscr) ) {
if (dscr.idVendor == vid && dscr.idProduct == pid) {
if (idx == cur_idx++ ) {
int rv = libusb_open(list[i], &dev_handle);
if (!rv) {
if (libusb_kernel_driver_active(dev_handle, 0)) {
// Probably should re-attach, but we don't!!!
libusb_detach_kernel_driver(dev_handle, 0);
}
rv = libusb_claim_interface(dev_handle, 0);
if (!rv) {
interface = 0;
rv = libusb_set_interface_alt_setting(dev_handle,
0, 0);
if (rv) {
libusb_close(dev_handle);
dev_handle = NULL;
}
alt_setting=0;
} else {
libusb_close(dev_handle);
dev_handle=NULL;
}
} else {
printf ( "Unable to open device idx: %d, ret: %d\n",
idx, rv );
}
}
}
}
}

if (!dev_handle) {
printf ( "Device not opened.\n" );
}
libusb_free_device_list(list,1);
}

The change I made was the libusb_kernel_driver_active if statement that finally does libusb_detach_kernel_driver function. I haven't tried this solution in any other context, so it may not be general.

Does this change make sense?

By: Dennis

Dennis — Thu, 25 Mar 2010 15:47:49 +0000

Glad it’s working. If you haven’t already, you’ll probably want to download fx2lib from the latest github master as opposed to 0.1 There are quite a few fixes, new samples, better build system and other things. I’m about ready to tag it 0.2 but I’ve been waiting on giving it a new website/home.

By: joebre

joebre — Thu, 25 Mar 2010 05:17:06 +0000

Sorry, I did a mistake… in the EProm image I got the old version of fw.c, this explains what I was seeing. Using your fw.c the throughput goes immediately and stably up to 43 MB/s. Thanks again for your support.

Job

By: joebre

joebre — Thu, 25 Mar 2010 04:25:53 +0000

Hi, thanks for your rapid answer.
I used your code as it comes from your web site, which I suppose has already the changes you’re speaking about (correct?). Yes I tried on several machines both Vista and XP and the throughput seems kind of hardwired to a maximum of 35/36 MB/S. You are right at the end I’ll use a synchronous slave fifo approach. At this stage of the project I need just to get a list of requirements for the host and to validate the throughput for Bulk unidirectional transfers (IN). 36 MB/s is good but it gives me a really small margin.

By: Dennis

Dennis — Wed, 24 Mar 2010 15:41:46 +0000

Been a while since I tried. Is there much different about streamer.exe and CyStream? I got it to go faster by eliminating any work the firmware was doing that wasn’t involved with committing the packets. Did you make those changes?

It’s a good learning activity to see how fast you can get it to go, but in the end, you’ll probably use slave fifo or gpif to transfer data from a peripheral directly through the buffers to the PC. We do this at 43MB/s which seems about as fast as the host will handle it.

Lastly, have you tried more than one machine to see if you get different results? You can post messages and firmware bits to the fx2lib mailing list too by the way: http://bit.ly/9xj8M5

By: joebre

joebre — Wed, 24 Mar 2010 15:31:32 +0000

Hi, first of all great job !
Just a question… I built your cystream using the latest FX2Lib, I programmed the binary into the EPROM of my custom EZ-USB board. Everything worked well at the first trial. Now the question… when I use your firmware in conjunction with the Streamer.exe delivered by Cypress I only get up tu a maximum of 36 MB/s in bulk mode which is quite far from the results you got. I’ve a IHC9 as host controller which should guarantee the maximum bandwidth… Where do you think is the problem? did you ever tried to use Streamer.exe of Cypress? with which results ?
Thanks Joebre

By: Dennis

Dennis — Thu, 02 Jul 2009 15:01:44 +0000

The fx2load package has some example of talking to the device with libusb-1.0. You can see sending vendor commands and doing bulk reads. I use that in the speed.py file too. Really though, everyone’s device is different so I haven’t found much utility in adding a host side example. Perhaps I’ll add a CyStream C++ equivalent that uses libusb0 one of these days.

By: bali.asur

bali.asur — Thu, 02 Jul 2009 11:37:52 +0000

Dennis:

Do you have any samples of your host application side
code?

Regards,

bali