Image Courtesy of SiFive, Inc.
I recently picked up the SiFive HiFive 1 Rev B RISC-V microcontroller on Crowd Supply. According to the SiFive product page, the HiFive 1 Rev B is “an Arduino-compatible development board featuring the SiFive Freedom E310-G002 (FE310-G002) SoC plus a ESP32-SOLO-1 Wi-Fi and Bluetooth module”. I have seen examples for this board written in C, Rust, and TinyGo. Having not used Rust as much as I would like, I wanted to start there for development on this platform. Here is a thorough write-up of the process on Windows 11 via Windows Subsystem for Linux (February 2023).
Process
This post assumes that you already have a properly configured (basic) Ubuntu 20.04 WSL install. Installation of Ubuntu on WSL is out of the scope of this post, although more information can be found here
Prepare WSL for USB Devices
Following the provided Microsoft Documentation, the first step to prepare WSL for USB is to run the following commands:
sudo apt install linux-tools-5.4.0-77-generic hwdata
sudo update-alternatives --install /usr/local/bin/usbip usbip /usr/lib/linux-tools/5.4.0-77-generic/usbip 20
Once complete, it’s important to ensure you have USB devices available on the host Windows 11 machine to passthrough. That can be accomplished with the following command (run in Powershell as Administrator):
usbipd wsl list
If an error is encountered stating that the usbipd cmdlet cannot be found (or anything similar), my first suggestion would be to update WSL (older versions of WSL didn’t have USB support). That can be done with two commands (again in an Administrator Powershell).
wsl --update
wsl --shutdown
Once you are able to verify that you have devices available, we can continue to attaching the USB device to a WSL instance.
It should look something like this:
PS C:\WINDOWS\system32> usbipd wsl list
BUSID VID:PID DEVICE STATE
1-10 0b05:185c Realtek Bluetooth Adapter attached
1-12 1366:1061 JLink CDC UART Port (COM9), JLink CDC UART Port (COM8), B... Not attached
Attaching a USB Device to WSL
Our SiFive HiFive 1 Rev B uses a SEGGER JLink integration to communicate with the computer. We can see above that our board has a BUSID of 1-12. We will need to note that for a future step.
Next, we want to identify the active distributions for WSL that we have on our computer. There is a set of WSL flags that can help us with this. (again in an Administrator Powershell)
wsl --list --verbose
For this post, we will be using the name Ubuntu-20.04.
To attach the USB device to our WSL instance, issue the following command (matching the two flags to the values we found above):
usbipd wsl attach --busid 1-12 --distribution Ubuntu-20.04
Installing the JLink software on our WSL VM
Some trickery is needed to download the JLink package from their website programatically. To accept the license agreement, download, and install the .deb package (explicitly for x86_64 architectures), run the following:
curl 'https://www.segger.com/downloads/jlink/JLink_Linux_V784f_x86_64.deb' --data-raw 'accept_license_agreement=accepted&submit=Download+software' --output JLink_Linux_x86_64.deb
sudo dpkg -i JLink_Linux_x86_64.deb
sudo apt-get -f install
Installing Rust via Rustup
rustup is the installer for the Rust Programming Language. For WSL, installation is managed with the following command:
curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh
You will need to select the default install for the purposes of this post. I ended up with this version: rustc 1.67.1
Installing cargo-generate
To install cargo-generate, run the next command:
cargo install cargo-generate
Installing RISC-V Compilation Target
To use our board, we will need a special compilation target. To install it:
rustup target add riscv32imac-unknown-none-elf
Installing SiFive GNU Toolchain for RISC-V
To install the toolchain, we will need to download and unpack a file from the SiFive website. It’s no longer accessible (via their site) to my knowledge, but a direct link to their download server still works as of February 2023.
The last chmod may or may not be optional… I didn’t bother to check.
curl https://static.dev.sifive.com/dev-tools/freedom-tools/v2020.12/riscv64-unknown-elf-toolchain-10.2.0-2020.12.8-x86_64-linux-ubuntu14.tar.gz --output /home/{your username}/riscv64-unknown-elf-toolchain-10.2.0-2020.12.8-x86_64-linux-ubuntu14.tar.gz
tar -xvf /home/{your username}/riscv64-unknown-elf-toolchain-10.2.0-2020.12.8-x86_64-linux-ubuntu14.tar.gz
chmod +x /home/{your username}/riscv64-unknown-elf-toolchain-10.2.0-2020.12.8-x86_64-linux-ubuntu14/bin/riscv64-unknown-elf-gdb
Then, add the following to your $PATH in .bashrc:
export PATH="$PATH:/home/{your username}/riscv64-unknown-elf-toolchain-10.2.0-2020.12.8-x86_64-linux-ubuntu14/bin"
Starting the JLink GDB Server
Starting the GDB server at this point is a fairly straightforward process. Just one command:
JLinkGDBServer -device FE310 -if JTAG -speed 4000 -port 3333 -nogui
Building and Deploying the Example Rust Code
First, we need to instantiate the new application:
cargo generate --git https://github.com/riscv-rust/riscv-rust-quickstart
After naming the app, enter the new app’s directory:
cd {app name}
In the Cargo.toml file, I needed to make one adjustment. I bumped the dependency riscv-rt to 0.11.0 from 0.10.0. My final dependencies looked like this:
[dependencies]
embedded-hal = "0.2.7"
hifive1 = { version = "0.10.0", features = ["board-hifive1-revb"] }
panic-halt = "0.2.0"
riscv = "0.10.0"
riscv-rt = "0.11.0"
To run the LED Blink example, two final commands will be needed:
cargo build --example leds_blink
cargo run --example leds_blink
Additionally, to view the serial console, you may try the following command:
sudo screen /dev/ttyACM0 115200
Final Thoughts
I’m excited to try writing some of my own Rust code for the SiFive HiFive 1 Rev B here in the coming weeks. I was admittedly late to the party (this board was released in April 2019), but I still see value in getting into the RISC-V architecture, especially in such an approachable form factor. If you’d like to pick one up for yourself, check out the Crowd Supply page!