Building an Octa-core 32-bit RISC-V PC on an FPGA board

x11-usb-litex-vexriscv

We built an octa-core 32-bit RISC-V PC running the X Window System (X11) on the Wukong board, an FPGA board from Qmtech.
The USB-connected keyboard and mouse use the Wireless Combo MK245 NANO from Logitech, known in Japan as Logicool.
This PC is based on https://github.com/litex-hub/linux-on-litex-vexriscv etc.

Linux on LiteX-VexRiscv

litex-vexriscv-console

The Linux on LiteX-VexRiscv uses 32-bit RISC-V VexRiscv as a soft microprocessor.
A SoC around the VexRiscv is created using LiteX as the SoC builder and LiteX’s cores.

RISC-V PC

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

  • RISC-V single board computer
    • Qmtech Wukong board
    • Alternative to Pmod usb_host_x4
  • USB wireless keyboard mouse combo
  • HDMI display
  • MicroSD
  • USB cable (USB-UART)

The main specifications of the RISC-V PC based on the Wukong board are as follows.

  • CPU: Octa-core 32-bit RISC-V
    • ISA: RV32IMAFDC + AES custom extension
    • Operating frequency: 100 MHz
  • DRAM: 256 MB
  • Ethernet: 100/1000 Mbps
  • USB: 2 ports (max 4 ports)
  • Display resolution: 1024×600
  • Storage
    • MicroSD: for OpenSBI, Linux & rootfs

Summary

We built an octa-core 32-bit RISC-V PC running the X Window System (X11) on the Qmtech Wukong board using modified LiteX/VexRiscv and others.
The feature of this PC is that the modified LiteX/VexRiscv realizes the USB host function.
We think it is a good point that many applications can be diverted by making the ISA of this CPU the same as that of the SaxonSoc.