[Discuss-gnuradio] usrp simultaneous tx / rx fix

[Eric Blossom]

Matt and I have just checked in some changes that fix problems we
were seeing when trying to run the Tx and Rx side of the USRP
simultaneously.  

(1) Under some of the newer kernels, the second open was killing the
first.  That problem was tracked down to the libusb
usb_set_configuration call and what I suspect are changes in the usbfs
kernel module.  Eliminating the call fixes the problem under
GNU/Linux.  Please let me know if this change breaks any other
OS's.  If so, we'll need some configure magic to work around it.

(2) We also had a problem where opening the Rx side would screw up the
Tx side signal processing path.  This was related to how various reset
signals were handled in the verilog.

The usrp CVS module has been updated, and it includes a new rbf file.
You'll want to update and build usrp to pick this up as well as the
host side changes.  The rbf is also available for manual download at
http://comsec.com/usrp/usrp_fpga_rev2_2005_11_15.rbf

Please let us know if simultaneous Tx and Rx opens are working for you.
You should be able to have one process opening the Tx side, and
another process opening the Rx side, or one process opening both sides.
The easiest way to test is to run usrp_siggen.py and usrp_fft.py in
separate windows.

Thanks!
Eric