Building a RISC-V computer on an Arty A7-35T FPGA board with SaxonSoc


We built a RISC-V computer running the X Window System (X11) and using the SaxonSoc on an Arty A7-35T FPGA board from Digilent.
We used a USB keyboard and a USB mouse, as shown in the xterm at the top left of the featured image.
This computer is based on and



The SaxonSoc is an SoC being developed by Charles Papon, the developer of the VexRiscv, and contributors.
Of course, the Soft CPU used in the SaxonSoc is the VexRiscv, a 32-bit RISC-V.
In the dev-0.3 branch currently under development, the supported FPGA boards are Radiona ULX3S, Digilent’s Arty A7 and Nexys A7.

RISC-V computer

We built a RISC-V computer with the following configuration.

  • RISC-V single board computer
    • Digilent Arty A7-35T
    • Alternative to Pmod usb_host_x4
      • USB connector to DIP adapter x 2
      • Breadboard, jumper wires
    • Digilent Pmod VGA
    • Digilent Pmod MicroSD
  • USB keyboard & mouse
  • VGA display
  • MicroSD
  • USB cable (power supply & USB-UART)

The main specifications of the RISC-V computer based on the Arty A7-35T are as follows.

  • CPU: Dual-core 32-bit RISC-V
    • ISA: RV32IMAFDC + AES custom extension
    • Operating frequency: 100 MHz
  • DRAM: 256 MB
  • Ethernet: 100 Mbps
  • USB: 2 ports
  • Display resolution: 1024×768
  • Storage
    • Onboard Flash: for OpenSBI & U-Boot
    • MicroSD: for Linux & rootfs


We built a RISC-V computer running the X Window System (X11) on an Arty A7-35T with the SaxonSoc.
The feature of this computer is that we can use a USB keyboard and a USB mouse.
We think it’s good to be able to use the Window Maker as a window manager.