PlutoLink is a simple RF transceiver implementation using the ADALM-PLUTO RF Learning Module. The host-side interface is UART-compatible and two PlutoLink setups can be used to form a simple link between MCUs.
The RF processing is done exclusively in the Zynq FPGA fabric and is designed to be portable to other non-Zynq FPGAs. The Zynq ARM core is used exclusively for radio management and debug support. TX and RX can occur theoretically anywhere in the 325 MHz to 3.8 GHz range that is supported by the module, but operation is expected to be done by licensed HAMs in one of the allowable bands (probably >2GHz).
This is a proof-of-concept project that is intended to explore the use of the AD9363 RF transceiver with FPGAs to build low-power and low-cost transceiver modules for use in Cubesats. The Zynq will be replaced in actual cubesats with a low-cost FPGA (probably a Spartan or equivalent) and a low-power microcontroller (probably a simple Cortex-M0).
The ADALM-PLUTO module is an Analog Devices product and instructions are located in a wiki.
This GitHub project is an adaptation of the plutosdr-fw GitHub project and includes only the rules that are needed to build the *.frm image files that get used during USB mass-storage flashing. If you need to do a DFU update (if you've bricked your device), use the official DFU image and then do a USB mass-storage upgrade to PlutoLink.
Prep:
sudo apt-get install git build-essential fakeroot libncurses5-dev libssl-dev ccache
sudo apt-get install dfu-util u-boot-tools device-tree-compiler mtools
sudo apt-get install bc cpio zip unzip rsync file wget xvfb flex bison
git submodule update --recursive
Actual build (assumes Xilinx is installed in ~/Xilinx/)
export CROSS_COMPILE=arm-linux-gnueabihf-
export PATH=$PATH:~/Xilinx/Vitis/2021.2/gnu/aarch32/lin/gcc-arm-linux-gnueabi/bin
export VIVADO_SETTINGS=~/Xilinx/Vivado/2021.2/settings64.sh
make
Use the mass-storage update procedure that can be found in the Pluto wiki: https://wiki.analog.com/university/tools/pluto/users/firmware
- Mount the mass-storage device
- Copy the "boot.frm" and "pluto.frm" files from the build folder to the root of the mass-storage device
- Eject the mass-storage device but DO NOT UNPLUG the Pluto module
- Wait for update to finish and the Pluto module to update and reboot
sudo mount /dev/sdX1 /mnt/pluto
sudo cp plutolink.frm /mnt/trswany/pluto.frm
sudo cp boot.frm /mnt/pluto/
sudo eject /dev/sdX
If the flashing fails for any reason, use the DFU update procedure and the *.dfu files in the official Pluto release. Once the recovery is complete, perform the mass-storage procedure again with the desired firmware.
Three of the Zynq's PL IO pins have been repurposed for use in the UART that interfaces with the radio link. These pins are conveniently exposed on a header on the PLUTO PCBA.
Warning: These pins are all 1.8V logic.
- Zynq pin M12, UART TX, output, Pluto header pin L12N
- Zynq pin K13, UART RX, input, Pluto header pin L10P
- Zynq pin R10, UART CTS, output, Pluto header pin L24N
The FTDI TTL-232RG-VREG1V8-WE has 1.8V logic and is compatible with this UART. The black wire is ground (connect to Pluto ground), the yellow wire is RXD (connect to Pluto TX L12N), the orange wire is TXD (connect to Pluto RX L10P), and the green wire is CTS (connect to Pluto CTS L24N).