Yimin Gu's PYNQSDR Hat Turns Your Digilent PYNQ-Z1 Into an Openwifi-Capable Software-Defined Radio
Clever board maintains full FPGA functionality while boasting PlutoSDR and openwifi compatibility.
Programmer and maker Yimin Gu has launched an add-on accessory for the Digilent PYNQ-Z1 field-programmable gate array (FPGA) development board which gives it software-defined radio capabilities: the PYNQSDR Hat.
"Both software-defined radio and FPGA are interesting," Gu writes by way of background to the project. "Especially, the combination of [Analog Devices] AD936X RF transceiver and [AMD Xilinx] ZYNQ 7020-level FPGA SoC [System on Chip] is capable of running openwifi.
"Price has been keeping average DIYers away from this kind of platform," Gu continues, "as evaluation boards from ADI and Xilinx are both extremely expensive. Cheaper ones like [the] AntSDR exist, but [it] seems all of them have tied the RF and ZYNQ chip together, so these are not suitable for generic ZYNQ development any more."
The PYNQSDR Hat aims to solve that. Rather than combining the radio chip and FPGA on a single board, it acts as an add-on to a lightly-modified Digilent PYNQ-Z1 development board — providing direct access to software-defined radio capabilities while still allowing the FPGA to be used separately as and when required.
"This provides openwifi and PlutoSDR functionalities," Gu explains, referring to an open source IEEE 802.11 baseband FPGA design and Analog Devices' PlutoSDR firmware originally designed for the ADALM-PLUTO SDR, "meanwhile keeping the major if not all functions of PYNQ-Z1 intact, with [a] summed price potentially lower than all currently available openwifi-capable platforms."
The PYNQSDR HAT is available to buy on its own for $125 or with a PYNQ-Z1 which has been modified with replacement zero-ohm PMOD resistors for $299 on Gu's Tindie store. Design files for the board have been published to GitHub under the reciprocal GNU General Public License 3, while Gu gave a talk on the project at FOSDEM '22.
