SPARTAN FPGA on USRP2

GNU Radio
1

Hi,
My research group is in the process of exploring about the
purchase
of USRP2 which employs SPARTAN-3-2000. In this regard, I had a few
queries:

  1. Is there some room leftover on the SPARTAN-3-2000 for USRP
    programming? -
    Many people whom I contacted were of the opinion that there is not much
    room
    left.

  2. What are the pros and cons of the ability to program the FPGA?
    a. According to Wikipedia (wrt USRP2),

“Xilinx’s free programming tool, ISE WebPACK, is not compatible with the
FPGA used for USRP. None of Xilinx’s tools are open source, and the
compatible tool (ISE Foundation) is not free of cost, so it is harder to
compile the USRP2 firmware”.
1. Is this statement true?
2. If it is true, is there no other alternative to buying
the
Xilinx tool and to what degree is the incompatibility ie does it allow
basic
programming of the FPGA or not?

  1. I would like to get a better idea of how I could program the Spartan
    III
    FPGA - basic or extensive? How often would one re-program the FPGA? -
    Again
    here, people from Xilinx etc were of the opinion that most of the
    programming would be on the gnu-radio and not on the FPGA and very
    rarely is
    the FPGA touched.

I had enquired with the USRP folks and they advised me to contact Xilinx
in
this regard. People from Xilinx redirected me to the gnuradio lists.

Thanks,
Yashas

2

On 12/07/2009 10:52 PM, yashas nataraj wrote:

Hi,
My research group is in the process of exploring about the
purchase of USRP2 which employs SPARTAN-3-2000. In this regard, I had
a few queries:

  1. Is there some room leftover on the SPARTAN-3-2000 for USRP
    programming? - Many people whom I contacted were of the opinion that
    there is not much room left.

In the USRP1 (which has an Altera Cyclone) there is not much space left
unless you take something else out.

In the USRP2 (Spartan 3-2000), there are many multipliers left (about
30), many logic slices (about 40%), but almost no Block RAMs (maybe 3 or
4 depending on how you set it up). You can always remove functionality
which you are not using, however.

  1. What are the pros and cons of the ability to program the FPGA?
    a. According to Wikipedia (wrt USRP2),
    “Xilinx’s free programming tool, ISE WebPACK, is not compatible with the
    FPGA used for USRP. None of Xilinx’s tools are open source, and the
    compatible tool (ISE Foundation) is not free of cost, so it is harder to
    compile the USRP2 firmware”.
    1. Is this statement true?

Correct. The Spartan 3-2000 will only work with the pay versions of
Xilinx tools, not the free versions.

           2. If it is true, is there no other alternative to buying

the Xilinx tool and to what degree is the incompatibility ie does it
allow basic programming of the FPGA or not?

The only alternatives to buying the tool are:

  • Get it for free, which may be possible if you are at a university or
    have a very good relationship with your Xilinx applications engineer
  • Find someone else to compile it for you and send you the bit file.
  1. I would like to get a better idea of how I could program the Spartan
    III FPGA - basic or extensive? How often would one re-program the FPGA?
  • Again here, people from Xilinx etc were of the opinion that most of
    the programming would be on the gnu-radio and not on the FPGA and very
    rarely is the FPGA touched.

The vast majority of users never need to change the FPGA code. It is
only if you want to do something very specialized that you need to
change it.

You can change the program as many times as you like, since it is stored
in the SD card, not on the board.

Matt