Hello, I have followed the exact same steps as shown in this video: https://www.youtube.com/watch?v=M9ntwQie9vs to create a custom RFNoC Gain block. I successfully built the FPGA bitstream and booted the E310 device with it. After flashing, I confirmed that the RFNoC blocks were correctly loaded. The output is: RFNoC blocks on this device: - 0/Gain#0 - 0/Radio#0 Static connections on this device: - 0/SEP#0:0 ==> 0/Radio#0:0 - 0/Radio#0:0 ==> 0/SEP#0:0 - 0/SEP#1:0 ==> 0/Radio#0:1 - 0/Radio#0:1 ==> 0/SEP#1:0 - 0/SEP#2:0 ==> 0/Gain#0:0 - 0/Gain#0:0 ==> 0/SEP#2:0 In addition to generating the bitstream, I also created and included the required .yml files — specifically the block descriptor (gain.yml) and image core (e310_rfnoc_image_core.yml). I confirmed that the image builder detects them successfully when using --log-level debug. [image: Screenshot from 2025-06-30 11-03-14.png] However, when I try to recreate the block diagram in GNU Radio Companion, following the same structure as shown in the video, I encounter the following error during Python code generation: Generating: "/home/aufer/Projects/rfnoc-gain/rfnoc_gain_trial.py" Generate Error: Undefined Failure Traceback (most recent call last): File "/home/aufer/gnuradio-install/lib/python3.12/site-packages/gnuradio/grc/gui/Application.py", line 758, in _handle_action generator.write() File "/home/aufer/gnuradio-install/lib/python3.12/site-packages/gnuradio/grc/core/generator/top_block.py", line 86, in write for filename, data in self._build_python_code_from_template(): ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/home/aufer/gnuradio-install/lib/python3.12/site-packages/gnuradio/grc/core/generator/top_block.py", line 135, in _build_python_code_from_template connections=self._connections(), ^^^^^^^^^^^^^^^^^^^ File "/home/aufer/gnuradio-install/lib/python3.12/site-packages/gnuradio/grc/core/generator/top_block.py", line 328, in _connections code = template.render( ^^^^^^^^^^^^^^^^ File "/usr/lib/python3/dist-packages/mako/template.py", line 438, in render return runtime.*render(self, self.callable*, args, data) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/usr/lib/python3/dist-packages/mako/runtime.py", line 874, in _render _render_context( File "/usr/lib/python3/dist-packages/mako/runtime.py", line 916, in _render_context _exec_template(inherit, lclcontext, args=args, kwargs=kwargs) File "/usr/lib/python3/dist-packages/mako/runtime.py", line 943, in *exec_template callable*(context, *args, **kwargs) File "memory:0x77b7681a8ce0", line 32, in render_body File "/usr/lib/python3/dist-packages/mako/runtime.py", line 230, in *str* raise NameError("Undefined") NameError: Undefined This occurs when GRC attempts to generate the .py file. Could you please advise what might be missing or misconfigured to cause this “Undefined” error? Best regards,

- 0/Gain#0
- 0/Radio#0

- 0/SEP#0:0 ==> 0/Radio#0:0
- 0/Radio#0:0 ==> 0/SEP#0:0
- 0/SEP#1:0 ==> 0/Radio#0:1
- 0/Radio#0:1 ==> 0/SEP#1:0
- 0/SEP#2:0 ==> 0/Gain#0:0
- 0/Gain#0:0 ==> 0/SEP#2:0

The YAML files look fine... which version of UHD and GNU Radio are you using? --M On Mon, Jun 30, 2025 at 1:04 PM Ahmet Hes <nirkicatal1@gmail.com> wrote: > Hello, > > I have followed the exact same steps as shown in this video: > https://www.youtube.com/watch?v=M9ntwQie9vs to create a custom RFNoC Gain > block. I successfully built the FPGA bitstream and booted the E310 device > with it. > > After flashing, I confirmed that the RFNoC blocks were correctly loaded. > The output is: > RFNoC blocks on this device: > > > - 0/Gain#0 > - 0/Radio#0 > > Static connections on this device: > > - 0/SEP#0:0 ==> 0/Radio#0:0 > - 0/Radio#0:0 ==> 0/SEP#0:0 > - 0/SEP#1:0 ==> 0/Radio#0:1 > - 0/Radio#0:1 ==> 0/SEP#1:0 > - 0/SEP#2:0 ==> 0/Gain#0:0 > - 0/Gain#0:0 ==> 0/SEP#2:0 > > In addition to generating the bitstream, I also created and included the > required .yml files — specifically the block descriptor (gain.yml) and > image core (e310_rfnoc_image_core.yml). I confirmed that the image builder > detects them successfully when using --log-level debug. > > [image: Screenshot from 2025-06-30 11-03-14.png] > > However, when I try to recreate the block diagram in GNU Radio Companion, > following the same structure as shown in the video, I encounter the > following error during Python code generation: > > Generating: "/home/aufer/Projects/rfnoc-gain/rfnoc_gain_trial.py" > Generate Error: Undefined > > Failure > > Traceback (most recent call last): > File > "/home/aufer/gnuradio-install/lib/python3.12/site-packages/gnuradio/grc/gui/Application.py", > > line 758, in _handle_action > generator.write() > File > "/home/aufer/gnuradio-install/lib/python3.12/site-packages/gnuradio/grc/core/generator/top_block.py", > > line 86, in write > for filename, data in self._build_python_code_from_template(): > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > File > "/home/aufer/gnuradio-install/lib/python3.12/site-packages/gnuradio/grc/core/generator/top_block.py", > > line 135, in _build_python_code_from_template > connections=self._connections(), > ^^^^^^^^^^^^^^^^^^^ > File > "/home/aufer/gnuradio-install/lib/python3.12/site-packages/gnuradio/grc/core/generator/top_block.py", > > line 328, in _connections > code = template.render( > ^^^^^^^^^^^^^^^^ > File "/usr/lib/python3/dist-packages/mako/template.py", line 438, in > render > return runtime.*render(self, self.callable*, args, data) > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > File "/usr/lib/python3/dist-packages/mako/runtime.py", line 874, in > _render > _render_context( > File "/usr/lib/python3/dist-packages/mako/runtime.py", line 916, in > _render_context > _exec_template(inherit, lclcontext, args=args, kwargs=kwargs) > File "/usr/lib/python3/dist-packages/mako/runtime.py", line 943, in > > *exec_template callable*(context, *args, **kwargs) > File "memory:0x77b7681a8ce0", line 32, in render_body > File "/usr/lib/python3/dist-packages/mako/runtime.py", line 230, in > *str* > raise NameError("Undefined") > NameError: Undefined > > This occurs when GRC attempts to generate the .py file. > > Could you please advise what might be missing or misconfigured to cause > this “Undefined” error? > > Best regards, > > _______________________________________________ > USRP-users mailing list -- usrp-users@lists.ettus.com > To unsubscribe send an email to usrp-users-leave@lists.ettus.com >

- 0/Gain#0
- 0/Radio#0

- 0/SEP#0:0 ==> 0/Radio#0:0
- 0/Radio#0:0 ==> 0/SEP#0:0
- 0/SEP#1:0 ==> 0/Radio#0:1
- 0/Radio#0:1 ==> 0/SEP#1:0
- 0/SEP#2:0 ==> 0/Gain#0:0
- 0/Gain#0:0 ==> 0/SEP#2:0

UHD 4.8.0.0-0-g308126a4 GNURadio version 3.10.9.2 Martin Braun <martin.braun@ettus.com>, 1 Tem 2025 Sal, 15:12 tarihinde şunu yazdı: > The YAML files look fine... which version of UHD and GNU Radio are you > using? > > --M > > On Mon, Jun 30, 2025 at 1:04 PM Ahmet Hes <nirkicatal1@gmail.com> wrote: > >> Hello, >> >> I have followed the exact same steps as shown in this video: >> https://www.youtube.com/watch?v=M9ntwQie9vs to create a custom RFNoC >> Gain >> block. I successfully built the FPGA bitstream and booted the E310 device >> with it. >> >> After flashing, I confirmed that the RFNoC blocks were correctly loaded. >> The output is: >> RFNoC blocks on this device: >> >> >> - 0/Gain#0 >> - 0/Radio#0 >> >> Static connections on this device: >> >> - 0/SEP#0:0 ==> 0/Radio#0:0 >> - 0/Radio#0:0 ==> 0/SEP#0:0 >> - 0/SEP#1:0 ==> 0/Radio#0:1 >> - 0/Radio#0:1 ==> 0/SEP#1:0 >> - 0/SEP#2:0 ==> 0/Gain#0:0 >> - 0/Gain#0:0 ==> 0/SEP#2:0 >> >> In addition to generating the bitstream, I also created and included the >> required .yml files — specifically the block descriptor (gain.yml) and >> image core (e310_rfnoc_image_core.yml). I confirmed that the image >> builder >> detects them successfully when using --log-level debug. >> >> [image: Screenshot from 2025-06-30 11-03-14.png] >> >> However, when I try to recreate the block diagram in GNU Radio Companion, >> following the same structure as shown in the video, I encounter the >> following error during Python code generation: >> >> Generating: "/home/aufer/Projects/rfnoc-gain/rfnoc_gain_trial.py" >> Generate Error: Undefined >> >> Failure >> >> Traceback (most recent call last): >> File >> "/home/aufer/gnuradio-install/lib/python3.12/site-packages/gnuradio/grc/gui/Application.py", >> >> line 758, in _handle_action >> generator.write() >> File >> "/home/aufer/gnuradio-install/lib/python3.12/site-packages/gnuradio/grc/core/generator/top_block.py", >> >> line 86, in write >> for filename, data in self._build_python_code_from_template(): >> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ >> File >> "/home/aufer/gnuradio-install/lib/python3.12/site-packages/gnuradio/grc/core/generator/top_block.py", >> >> line 135, in _build_python_code_from_template >> connections=self._connections(), >> ^^^^^^^^^^^^^^^^^^^ >> File >> "/home/aufer/gnuradio-install/lib/python3.12/site-packages/gnuradio/grc/core/generator/top_block.py", >> >> line 328, in _connections >> code = template.render( >> ^^^^^^^^^^^^^^^^ >> File "/usr/lib/python3/dist-packages/mako/template.py", line 438, in >> render >> return runtime.*render(self, self.callable*, args, data) >> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ >> File "/usr/lib/python3/dist-packages/mako/runtime.py", line 874, in >> _render >> _render_context( >> File "/usr/lib/python3/dist-packages/mako/runtime.py", line 916, in >> _render_context >> _exec_template(inherit, lclcontext, args=args, kwargs=kwargs) >> File "/usr/lib/python3/dist-packages/mako/runtime.py", line 943, in >> >> *exec_template callable*(context, *args, **kwargs) >> File "memory:0x77b7681a8ce0", line 32, in render_body >> File "/usr/lib/python3/dist-packages/mako/runtime.py", line 230, in >> *str* >> raise NameError("Undefined") >> NameError: Undefined >> >> This occurs when GRC attempts to generate the .py file. >> >> Could you please advise what might be missing or misconfigured to cause >> this “Undefined” error? >> >> Best regards, >> >> _______________________________________________ >> USRP-users mailing list -- usrp-users@lists.ettus.com >> To unsubscribe send an email to usrp-users-leave@lists.ettus.com >> > _______________________________________________ > USRP-users mailing list -- usrp-users@lists.ettus.com > To unsubscribe send an email to usrp-users-leave@lists.ettus.com >

*Final Update:* I decided to ignore the warnings in GNU Radio and proceeded with the Python script. When I construct the graph as follows: radio_noc_block = graph.get_block("0/Radio#0") radio_block = uhd.rfnoc.RadioControl(radio_noc_block) rx_streamer = graph.create_rx_streamer(1, uhd.usrp.StreamArgs("fc32", "sc16")) graph.connect("0/Radio#0", 0, rx_streamer, 0) graph.commit() I’m able to receive samples successfully. However, when I insert my custom Gain block into the chain: radio_noc_block = graph.get_block("0/Radio#0") radio_block = uhd.rfnoc.RadioControl(radio_noc_block) rx_streamer = graph.create_rx_streamer(1, uhd.usrp.StreamArgs("fc32", "sc16")) graph.connect("0/Radio#0", 0, "0/Gain#0", 0, False) graph.connect("0/Gain#0", 0, rx_streamer, 0) print(graph) # Inspect the connections graph.commit() I no longer receive any samples. I would really appreciate your help in identifying what might be going wrong with the custom block connection.

Ahmet, this is too difficult to remote-diagnose. I suggest comparing your code to the rfnoc-gain example in UHD and see if you made a mistake in the Verilog implementation. --M On Wed, Jul 2, 2025 at 2:51 PM Ahmet Hes <nirkicatal1@gmail.com> wrote: > *Final Update:* > > I decided to ignore the warnings in GNU Radio and proceeded with the > Python script. > > When I construct the graph as follows: > > radio_noc_block = graph.get_block("0/Radio#0") > radio_block = uhd.rfnoc.RadioControl(radio_noc_block) > rx_streamer = graph.create_rx_streamer(1, uhd.usrp.StreamArgs("fc32", > "sc16")) > graph.connect("0/Radio#0", 0, rx_streamer, 0) > graph.commit() > > I’m able to receive samples successfully. > > However, when I insert my custom Gain block into the chain: > > radio_noc_block = graph.get_block("0/Radio#0") > radio_block = uhd.rfnoc.RadioControl(radio_noc_block) > rx_streamer = graph.create_rx_streamer(1, uhd.usrp.StreamArgs("fc32", > "sc16")) > graph.connect("0/Radio#0", 0, "0/Gain#0", 0, False) > graph.connect("0/Gain#0", 0, rx_streamer, 0) > print(graph) # Inspect the connections > graph.commit() > > I no longer receive any samples. > > I would really appreciate your help in identifying what might be going > wrong with the custom block connection. > > > >