This project implements a Raspberry Pico based Xilinx Virtual Cable (XVC). It allows using Raspberry Pico as a JTAG adapter for programming Xilinx FPGAs.

It is derived from the excellent pico-dirtyJtag project.

A special shoutout goes to https://github.com/tom01h for crazily improving the performance of this project - thank you!

The pinout is as follows:

Note: The Raspberry Pico is a 3.3v device. Ensure that the target device and the Pico are electrically compatible before connecting them.

Note: This project was tested with Vivado 2021.1, Raspberry Pi Pico as the JTAG programmer (XVC server), and EBAZ4205 'Development' FPGA Board in August 2021.

Update: This project was tested with Vivado ML Standard 2023.1, Raspberry Pi Pico as the JTAG programmer (XVC server), and EBAZ4205 'Development' FPGA Board in May 2023.

Update (April-2024): The xvc-pico-wifi version was tested successfully with Vivado v2023.1 (64-bit).

Shortcut: Upload the pre-built xvcPico.uf2 file to the Raspberry Pico Board. Done - skip to the next section.

Install dependencies:

sudo apt install cmake gcc-arm-none-eabi libnewlib-arm-none-eabi \
  libstdc  -arm-none-eabi-newlib git libusb-1.0-0-dev build-essential \
  make g   gcc

mkdir ~/repos
cd ~/repos

git clone https://github.com/raspberrypi/pico-sdk.git
cd pico-sdk; git submodule update --init

cd ~/repos
git clone https://github.com/kholia/xvc-pico.git

Build the host-side daemon:

cd ~/repos/xvc-pico/daemon
cmake .
make
sudo ./xvcd-pico  # run on the host computer, turn on the pico board before

Build the Raspberry Pico's firmware:

cd ~/repos/xvc-pico/firmware
export PICO_SDK_PATH=${HOME}/repos/pico-sdk
cmake .
make -j4

Grab xvcd-pico.exe from the builds folder of this repository itself.

You need to install the libusbK driver with Zadig (https://zadig.akeo.ie/).

OR

You can install the WinLibUSB driver from USB Drive Tool Application (https://visualgdb.com/UsbDriverTool/).

Credit goes to https://github.com/benitoss/ for these instructions.

On the host computer with the Raspberry Pi Pico connected, run the XVC Daemon Server.

./xvcd-pico

In Vivado, select the Add Xilinx Virtual Cable (XVC) option in the Hardware Manager and mention the IP address and the Port of the host computer.

If you see the End of startup status: LOW error message in Vivado, check the FPGA power supply's voltage and current ratings.

I found Maker Pi Pico Base really helpful for debugging GPIO stuff.

This URL says that Xilinx Virtual Cable (XVC) protocol allows (local or remote) Vivado to connect to a target FPGA for debug leveraging standard Xilinx standard debug cores like Integrated Logic Analyzer - ILA, Virtual Input/Output - VIO, and others. ILA works fine over our Raspberry Pico JTAG adapter. Vitis stuff is also supported.

If cost and ease-of-availability are the driving constraints (at the cost of speed), then this project is 'usable' and can probably suffice. If higher programming speed is a requirement, I recommend using xc3sprog or openFPGALoader with an FT2232H board.

This project might be one of the cheapest, most energy-efficient Vivado-Compatible JTAG programmers. I use this project as my "daily driver" now ;)

Writing ebaz4205_top.bit (371.6 KiB) takes only ~2.5 seconds now - thanks to tom01h. Don't overestimate the speed of human programmers and Vivado though ;)

$ time ./openFPGALoader -c xvc-client --port 2542 --file-type bin ebaz4205_top.bin
empty
detected xvcServer version v1.0 packet size 12288
freq 6000000 166.666667 166 0
a6 0 0 0
Open file DONE
Parse file DONE
load program
Load SRAM: [==================================================] 100.00%
Done
./openFPGALoader -c xvc-client --port 2542 --file-type bin ebaz4205_top.bin  0.00s user 0.01s system 0% cpu 7.389 total

It seems openFPGALoader is a lot slower than Vivado in programming devices via XVC!?

Writing corescore_0.bit (2 MiB) which uses ~100% FPGA LEs takes around ~9 seconds.

./openFPGALoader -c xvc-client --port 2542 --file-type bin ebaz4205_top.bin

Connect Pico's hardware UART pins to FPGA's UART.

#define UART_TX_PIN 0
#define UART_RX_PIN 1

Set UART of FPGA to 115200 baud rate.

Note: /dev/ttyACM(n) will appear when Pico's USB is connected.

• https://github.com/kholia/xvcpi
• https://github.com/kholia/xvc-esp32
• https://github.com/kholia/xvc-esp8266
• https://github.com/phdussud/pico-dirtyJtag/
• https://github.com/kholia/Colorlight-5A-75B
• https://github.com/fusesoc/blinky#ebaz4205-development-board