Re: [USRP-users] Recieve on two channels simultaneously USRP E310

[Rob Kossler]

Hi Ivan,

You should be able to build an FPGA image with 2 FFT blocks and 2 window blocks.  I have done something similar on the E310 where I have 2 FFT blocks and then 2 custom blocks which pass/discard selected FFT bins (and is actually reasonably similar to the window block).  A couple of points:

• You will want to create your own FFT IP component from the Vivado IP builder tool.  The Ettus FFT noc block includes a 4096 point FFT.  In order to conserve resources, you could reduce the size, change the option to be fixed size (rather than variable size), and change the architecture (from pipelined to radix-4 or radix-2).  Each of these will affect overall resources and performance.  If you need the FFT to keep up at the full radio rate, though, you probably need to stick with 'pipelined'.
• If your FFT is bigger than 512 points, you will need to set RESIZE_OUTPUT_PACKET=1 in the axi_wrapper so that it can change the outgoing packet size to match the incoming packet size.  Otherwise, the FFT output packets of 1024 points or more will be a problem for the E310.
• You will likely want to combine the FFT and window functionality into 1 new noc block.  My original plan of 2 FFTs and 2 custom blocks did not build, but when I combined the functionality into a total of 2 blocks (each with one FFT and one custom block), it built.  So, perhaps there is a non-negligible amount of overhead in having things in separate noc blocks. You could even try to combine all of your functionality into a single 2x2 noc block.
• Depending on whether or not you need Tx capability, you could potentially not include the DUC.  Also, if you plan to run at full radio rates such that you won't need a DDC, you could eliminate the DDC from the build.

My experience is with 3.13, 3.14, 3.15.  I have not tried any builds with the new 'master' branch (eventually becoming 4.0).  From what I understand about the new 'master', you could statically connect your noc blocks such that you might not need to do my 'trick' of putting multiple noc block functionality into a single noc block in order to save resources.

Rob

On Sat, Apr 4, 2020 at 2:04 PM Ivan Zahartchuk via USRP-users <address@hidden> wrote:

Yes, I really get an error
 The packing of instances into the device could not be ovailable, however, the unplaced instances require 9681 slices. Please analyze your design to determine if the number of LUTs, FFs, and / or control sets can be reduced.
ERROR: [Place 30-99] Placer failed with error: 'Detail Placement failed please check previous errors for details.'
beyed. There are a total of 13300 slices in the pblock, of which 8368 slices are available, however, the unplaced instances require 9681 slices. Please analyze your design to determine if the number of LUTs, FFs, and / or control sets can be reduced.
ERROR: [Place 30-99] Placer failed with error: 'Detail Placement failed please check previous errors for details.
But do not tell me if there are blocks in gnuradio to control gpio. The general idea is to implement an amplitude or phase direction finder on a given board. Perhaps you have any suggestions or examples. Because in programming on FPGAs I am unfortunately very weak and I need decent speed.

сб, 4 апр. 2020 г. в 20:50, Marcus D. Leech via USRP-users <address@hidden>:

On 04/04/2020 01:39 PM, Ivan Zahartchuk via USRP-users wrote:

Hello. Can I create a binary file with two fft blocks and two window blocks for usrp E310 for rfnoc? And if so, how ? The idea is to receive a signal from two channels simultaneously.

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There may not be enough room for two FFT blocks in the E310 FPGA.  But regardless, you'd need Xylinx Vivado tooling to generate up an RFNOC
  FPGA image that has the appropriate blocks generated into it. There is no "dynamic" generation of blocks in the FPGA.  The only "dynamic"
  part is the connection of those blocks across the cross-bar construct that RFNoC uses.

This document may be helpful:

https://kb.ettus.com/Getting_Started_with_RFNoC_Development

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