SpectrumX MEP RFSoC 4x2 SDR

This repository contains a PYNQ overlay which provides SDR functionality for the RFSoC 4x2 Development Board for the SpectrumX Mobile Experiment Platform (MEP) project. SpectrumX is a nexus for innovation in spectrum research, education, and national-level partnerships. More information can be found on the SpectrumX website.

The SDR overlay provides flexible software-controlled transmit and receive capability for the RFSoC 4x2 board. Data is transferred to and from the board to a PC over a 10Gbps SFP+ connection, using the QSFP28 connector and a Quad to Single SFP adapter.

• RFSoC 4x2 Development Board
• Intel 10GbE x520 SFP NIC (Or compatible alternative)
• QSFP to SFP+ Adapter
• SFP+ Direct Attach Cable (Or equivalent)
• PC with 10GbE capable NIC installed

Clone this repository on the RFSoC 4x2. Important: This repository uses Git submodules for external dependencies, so you must initialize them:

git clone --recursive https://github.com/spectrumx/mep-rfsoc-sdr.git
cd mep-rfsoc-sdr

Then build and install the package:

sudo `which python` -m pip install --upgrade pip build
sudo `which python` -m build
sudo `which python` -m pip install . -v

Finally, link and enable the service so that it runs on boot:

sudo ln -sf `python -c 'import importlib.resources; print(importlib.resources.files("mep_rfsoc_sdr") / "systemd" / "mep-rfsoc-sdr.service")'` /etc/systemd/system/mep-rfsoc-sdr.service
sudo systemctl daemon-reload
sudo systemctl enable mep-rfsoc-sdr

The bitstream and hardware description files are not included in the repo by default. The build hook fetches the official files from the release page at: https://github.com/spectrumx/mep-rfsoc-sdr/releases into dist/bitstream-v{version} and includes those files in the installed package. To override the official files, manually place sdr_bitstream.bit and sdr_bitstream.hwh in src/bitstream, then rerun the build and install commands above. The build hook will copy those user-provided files into dist/bitstream-v{version} and include them in the installed package.

The SDR image streams captured RF data over a UDP connection. I/Q data is sent in interleaved packets with a header providing timing and frequency information. Telemetry and commands are optionally sent over MQTT. This data stream can be received and parsed by utilties in the mep-examples repository.

To launch the UDP streaming script on the RFSoC 4x2, run:

sudo -E `which python` -m mep_rfsoc_sdr.start_capture_rx

The script configures the RFSoC overlay, tunes the ADC NCO, starts UDP streaming, and optionally enables a DAC transmit tone from the function-generator IP. If MQTT control is not available, command line flags can be used to set the default configuration:

Command line options:

The build scripts expect Vivado 2024.1 and a license for the XXV_Ethernet core. Source the Vivado environment script, the path will depend on the installation:

source /opt/Xilinx/Vivado/2024.1/settings64.sh

Initialize and build the Vivado project:

cd boards/RFSoC4x2/mep-sdr
init_design.bash --build

To only initialize the project, run init_design.bash without the build flag. This will create the Vivado project and instantiate the block design. The block design can then be manually opened in Vivado.

vivado mep-sdr.xdc