Hi,
On Fri, 4/24/09, Tony N. [email protected] wrote:
The short answer is that the PIC 18F4550 processor will not help.
USB needs a “host” (typically a PC) that times & controls each data
packet and a “device” to talk to. Optionally a hub is both a device
and relay of timing & data to further devices. Both the PIC processor
and the USRP are devices, and cannot talk to each other.
So USB device can only talk to USB Hub.Thanks for this clarification.
Also the USRP documentation says it needs “USB2”, which I
think means it needs the “High Speed” data transfer of USB2. Whereas
the PIC 18F4550 only supports the lower transfer speeds of USB1.1
I mentioned PIC16F4550 as an example for mcu that has a USB port.
Actually, I didn’t checked whether it supports HS or FS (Sorry for bad
example).
An easier path would be to look small processor boards such as those
that support embedded Linux. For instance the web page for the
Gumstix Overo Earth says it has a “USB HS Host” and a micro SD slot.
(Not micro SDHC - so you are limited to, I think, 4Gb cards.)
See:
http://gumstix.com/store/catalog/product_info.php?cPath=31&roducts_id=211
Thank you for your suggestion, but I’m looking for cheep and simple
method to load USRP firmware.
Best Regards,
Firas
Hi
2009/4/24 [email protected]:
An easier path would be to look small processor boards such as those
that support embedded Linux. For instance the web page for the
Gumstix Overo Earth says it has a “USB HS Host” and a micro SD slot.
(Not micro SDHC - so you are limited to, I think, 4Gb cards.)
See:
http://gumstix.com/store/catalog/product_info.php?cPath=31&roducts_id=211
Thank you for your suggestion, but I’m looking for cheep and simple method to load USRP firmware.
First I think you should verify that the USRP cannot permanently store
firmware in some way, maybe even contact Matt E.?
Programming for USB Host is unfortunately not simple, as it needs a
whole comms stack. It requires several months programming to get all
the functionality, though you can probably skip some parts for your
dedicated support for a single device. But take it from someone who
has done this you will have problems, and sooner or later you will
need to purchase or rent a USB Analyser to debug the comms. (This cost
was something like $20000 the last time I needed one!)
I think approx $150 for a board that runs Linux and you can be
confident will do the job is a bargain. 
Probably there are lots of suppliers of boards for embedded Linux, I
only mentioned one brand because I have heard good comments about
their products.
If you still decide you want to build your own USB Host you should at
least get Jan Axelson’s “USB Complete” book, which covers many of the
practicalities. If you can find it, the Mindshare book on USB System
Architecture by Don Anderson is easier to read than the official
standards at the USB Implementers Forum (www.usb.org).
Regards,
Tony
First I think you should verify that the USRP cannot permanently store
firmware in some way, maybe even contact Matt E.?
There is no way to store the FPGA image on there. You can store only a
very tiny cut down version of the FX2 firmware.
Matt