Quick Start

This section explains how to run RVComp on an FPGA board using a prebuilt bitstream and Linux image.

Please download the following files from the release page.

UART boot (Arty A7 35T or Nexys 4 DDR):

  • uart_fw_payload.bin: Linux image file for UART boot

  • uart_arty_a7.bit: Bitstream for Arty A7 35T (UART boot)

  • uart_nexys4ddr.bit: Bitstream for Nexys 4 DDR (UART boot)

MMC boot (Nexys 4 DDR only):

  • mmc_fw_payload.bin: Linux image for MMC boot

  • mmc_nexys4ddr.bit: Bitstream for Nexys 4 DDR (MMC boot)

Note

MMC boot requires a microSD card inserted into the Nexys 4 DDR board’s microSD slot. If an Ethernet cable is connected to the board, the network interface is available after boot.

Common:

  • tools.zip: Programs to communicate with the FPGA board via UART

Please unzip tools.zip.

Please make sure the necessary tools and the FPGA board are ready:

UART Boot (Arty A7 35T or Nexys 4 DDR)

  1. Connect the FPGA board to your PC.

  2. Download and extract uart_fw_payload.bin, uart_arty_a7.bit (for Arty A7 35T) or uart_nexys4ddr.bit (for Nexys 4 DDR), and the tools directory from the archive mentioned above, and place them in the same directory.

  3. Open PowerShell (Windows) or a terminal (Linux) and change to the directory from step 2.

  4. Determine which serial port the USB connection is using. You can see by executing cd tools && uv run findport. If this does not work, please see Checking the Serial Port below.

  5. Run the following command, replacing <port> with the value from step 4 (if you are not in the tools directory, please execute cd tools first). On success you should see Port <port> opened successfully..

    • Nexys 4 DDR: uv run term <port> 3000000 --linux-boot --linux-file-path ../uart_fw_payload.bin

    • Arty A7 35T: uv run term <port> 3000000 --linux-boot --linux-file-path ../uart_fw_payload.bin

  6. Launch Vivado and select Open Hardware Manager → Open Target → Auto Connect → Program Device.

  7. When prompted for the bitstream, please choose uart_arty_a7.bit if you use Arty A7, or uart_nexys4ddr.bit if you use Nexys 4 DDR, then click Program.

  8. The Linux image is transferred to the FPGA and boot begins. Once the login prompt appears, please log in as root (no password).

  9. To use Ethernet, configure the network interface:

    $ ip addr add <IP_ADDRESS>/<PREFIX_LEN> dev eth0
$ ip link set eth0 up

  10. Press Ctrl+C, then type :q to exit the serial console.

MMC Boot (Nexys 4 DDR only)

MMC boot on Nexys 4 DDR requires a microSD card. The mmc_fw_payload.bin file is a combined binary containing the Linux image and root filesystem; it is written to the beginning of the microSD card. The serial terminal is still used as a console, but it does not send the Linux image in this mode.

Writing the microSD card

Insert a microSD card into your host machine.

Linux:

Identify the block device node with lsblk or dmesg. Verify the device node carefully before proceeding; writing to the wrong device will permanently destroy data on that device.

$ diskutil unmountDisk /dev/sdX
$ sudo dd if=mmc_fw_payload.bin of=/dev/sdX bs=1M conv=fsync,notrunc status=progress
$ sync
$ diskutil eject /dev/sdX

Replace /dev/sdX with the actual device node of your microSD card (for example /dev/sdb). After the command completes, safely eject the card.

Windows (WSL):

Attach the microSD card to WSL, then use the same dd command as Linux above.

Booting from microSD card

  1. Insert the written microSD card into the microSD slot on the Nexys 4 DDR board.

  2. Connect the board to your PC via USB.

  3. Download and extract mmc_nexys4ddr.bit (for Nexys 4 DDR), and the tools directory from the archive mentioned above, and place them in the same directory.

  4. Determine which serial port the USB connection is using. You can see by executing cd tools && uv run findport. If this does not work, please see Checking the Serial Port below.

  5. Open a terminal and run the following command. No --linux-boot flag is needed because the serial tool is used only as a console in this mode:

    $ cd tools // if you are not already in the tools directory
$ uv run term <port> 3000000

  6. Launch Vivado and program the board with mmc_nexys4ddr.bit using Open Hardware Manager → Open Target → Auto Connect → Program Device.

  7. The bootrom copies the Linux image from the microSD card into DRAM and boots Linux. The root filesystem on the microSD card is mounted as /dev/mmcblk0. Once the login prompt appears, log in as root (no password).

  8. To use Ethernet, configure the network interface:

    $ ip addr add <IP_ADDRESS>/<PREFIX_LEN> dev eth0
$ ip link set eth0 up

  9. Press Ctrl+C, then type :q to exit the serial console.

Checking the Serial Port

You can check the serial port by running the following command in the tools directory: uv run findport (need to have uv installed). If this command does not work, please follow the instructions below for your operating system.

Windows

Please run the following command in PowerShell:

Get-CimInstance Win32_PnPEntity | Where-Object { $_.Caption -match 'COM' } | Select-Object Caption, DeviceID

Please identify the entry whose DeviceID contains FTDI; this corresponds to the FPGA board. It appears in the form USB Serial Device (COM*). Please note the COM port name.

WSL

Please follow the instructions in this article to attach USB devices to WSL. Please run usbipd list; the entry with VID:PID of 0403:6010 is usually the FPGA board. After attaching it, please follow the Linux instructions below.

Linux

Please run the following command in a terminal:

$ ls /dev/ttyUSB*

The available USB serial ports are listed. If only one FPGA board is connected as a USB serial device, it is typically /dev/ttyUSB1. When multiple USB serial devices are present, please run the command below for each port and look for a device where ID_VENDOR is Digilent:

$ udevadm info /dev/ttyUSB1 | grep ID_VENDOR=

Please record the /dev/ttyUSB* path assigned to the FPGA board.

Prebuilt Bitstream Parameters

The prebuilt bitstreams provided in the release are configured with the default settings in tools/setting.py.