Thanks Nate, But I want to clarify a bit. For the N3xx and X310 (I don't know about the E3xx), the problem is not the FFT size, but simply the packet size on the xbar is limited to a certain size and given that the FFT noc block presently ties the packet size to the output FFT size, this effectively limits the FFT size. Is this correct?
If so, then I will mention that it is an easy change in the FFT noc block to set RESIZE_OUTPUT_PACKET=1 in the axi_wrapper in order to decouple the output packet size from the FFT size and instead couple it to the input packet size. Rob On Wed, Sep 11, 2019 at 11:49 AM Nate Temple <nate.tem...@ettus.com> wrote: > Hi Rob, > > The N3xx (and E3xx) only support having an FFT size up to 512 due to the > page size. It'd be possible to modify the blocks to break up the FFT over > several packets but it is not currently implemented. The X310 as is > supports up to a 1024 point FFT. > > Regards, > Nate Temple > > On Mon, Sep 9, 2019 at 12:35 PM Rob Kossler via USRP-users < > usrp-users@lists.ettus.com> wrote: > >> Hi, >> I am having trouble running the FFT block of size 1024 on an N310. I am >> using the "rfnoc_rx_to_file" example program (UHD v3.14.1.0) to run it. It >> works with size 256 or 512. Additionally, I am able to run with 1024 if I >> switch to an X310 (same PC). Please let me know if you have any ideas... >> Rob >> >> *Here is the command that fails:* >> >> rfnoc_rx_to_file --args="type=n3xx" --nsamps=65536 --block-id=FFT_0 >> --block-args="spp=1024" --rate=125e6 --freq=2400e6 --radio-args="spp=1024" >> >> *The following is the output with error message:* >> >> Using radio 0, channel 0 >> Setting RX Rate: 125.000000 Msps... >> Actual RX Rate: 125.000000 Msps... >> >> Setting RX Freq: 2400.000000 MHz... >> Actual RX Freq: 2400.000000 MHz... >> >> Connecting 0/Radio_0 ==> 0/FFT_0 >> [WARNING] [RFNOC] Assuming max packet size for 0/Radio_0 >> Samples per packet: 1024 >> Using streamer args: block_id=0/FFT_0,spp=1024 >> Issuing stream cmd >> [ERROR] [RX FLOW CTRL] Error unpacking packet: ValueError: Bad CHDR or >> packet fragment >> >> [ERROR] [STREAMER] The receive packet handler caught a value exception. >> ValueError: Bad CHDR or packet fragment >> Error: Receiver error: ERROR_CODE_BAD_PACKET >> >> *Note that the following works fine with an X310* >> >> rfnoc_rx_to_file --args="type=x300" --nsamps=65536 --block-id=FFT_0 >> --block-args="spp=1024" --rate=100e6 --freq=2400e6 >> >> _______________________________________________ >> USRP-users mailing list >> USRP-users@lists.ettus.com >> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com >> >
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