Issues concerning the FPGA programming

Good morning,

I have several questions concerning the FPGA programming of the USRP2
and I
would appreciate if you could help me. First of all, I am using GNU
Radio
3.3.0 and Ubuntu 10.10.

One of the things I have not very clear is the role of the firmware on
the
aeMB. Reading the FAQ I found: “It performs configuration and status
reporting for all the FPGA peripherals, manages the control channel for
the
GbE transport, and handles RF daughterboard operation”. I would like to
know
if there is another source of information than read the code. I need to
change the FGPA code, so I suppose that I need to change the firmware
for
the aeMB processor too. Could you confirm me this point? In order to be
more
concrete, I have two different scenarios:

  1. One scenario consists in reprogram the FGPA with a complete new
    design. This would be only to use the USRP2’s FPGA connected directly
    to a
    signal generator through the LFRX and to an oscilloscope through the
    LFTX.
    It is a part of a simple DSP demo I need to perform. After that, I
    would
    program the FPGA with the original code.
    2. Another scenario consists in add a block (for example a filter)
    to
    the actual FPGA code using the free space it has. I read in the FAQ
    that
    around 22 of the multipliers are free and about the 60% of the logic
    area.
    The configuration would be the same as above (signal generator and
    oscilloscope).

Another thing I would like to check is the process to add a block to the
FPGA. These are the steps I have in mind to get the code

  1. Download the code using git clone git://
    git.ettus.com/ettus/fpga.git
  2. Use the branch ise12 typing git checkout ise12
  3. Go to the u2_rev3 folder

What is the next step to create the project for Xilinx ISE? Can I just
add
all the source files to a new project in ISE?

I suppose that when I modify the verilog files to add my block, then I
need
to modify also all the makefiles and go to the top folder to run make
clean
&& make bin
. Am I right?

I read in the mailing list archive that if I am going to use the raw
ethernet code, I should use the master branch and the ISE 10.x tool
instead
of the ise12 branch and ISE 12.x tool. Is this correct?

Seeking in the Xilinx website (
http://www.xilinx.com/ise/ossupport/index.htm ) I read that only Red Hat
and
SuSe have support. Have you noticed any issue related to Ubuntu? Should
I
change to Red Hat in order to avoid any problem?

I know that I ask for a lot of answers and I apologize but this is a new
field of study for me.

Thank you very much.

Greetings.

Eduardo Lloret.