Re: [Discuss-gnuradio] SSRP 7/13

[Eric Blossom]

On Tue, Jul 13, 2004 at 07:40:22PM -0500, David Carr wrote:
> Hi all,
> 
> The IO test board is complete and tested.  Pictures are in the I/O 
> test board section at: oscar.dcarr.org/ssrp/
> Secondly, I've succeeded in moving ~16MB/s from the test board to my 
> laptop using some simple bulk transfer firmware.  This is fast enough 
> but it seems a little slow considering I have the 82801DB (ICH4) 
> chipset.  I used 512 byte packets to fx2_programmer reading 4096 byte 
> chunks.  Any suggestions?

Use the fusb*.{h,cc} and test_fusb.c code out of the usrp tarball.

Using the standard libusb interface under linux xfers a maximum of 4kB
across the user/kernel boundary at a time, regardless of the arguments
that you pass, and the calls block until the requests complete.  The
"fast usb" code (fusb*.{h,cc}) uses the usbfs interface to submit
multiple USB request blocks asynchronously.  This allows us to sustain
over 32MB/sec.


> Does anyone have a vendor for 
> these or similar?  I'm also willing to try a photoresist PCB 
> technique, is 8mil resolution achieveable?

There are a ton of quick turn proto shops that will build you a few
boards for under $100.  You upload your gerbers and they ship you
boards in a few days.  Their processes typically handle 7mil space and
trace.  Here are a few starting points.

    http://www.google.com/search?q=pcb%20prototypes
    http://www.pcbexpress.com
    https://www.2justforyou.com/NASApp/sierraproject/jsp/tabs_welcome_home_.jsp

Eric