This is one of the first programs I have written in Rust, so it may be a little rough around the edges.
This is an embedded Rust program which runs on the Longan Nano board, and displays an animated fish tank on the Longan Nano's. The Longan Nano is a RISC-V development board which only costs $4.90, and comes with a tiny color LCD and a plastic case.
This program uses the embedded-graphics crate, so it should be fairly easy to port to other microcontrollers and displays, as long as the microcontroller is supported by Rust, and the display is supported by embedded-graphics.
The Longan Nano is supported by the longan-nano crate, which I previously tried out in a blog post.
Install Rust if you haven't already:
$ curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh
$ source $HOME/.cargo/env
$ which rustc
/home/ppelleti/.cargo/bin/rustc
$ rustc --version
rustc 1.46.0 (04488afe3 2020-08-24)
Add support for RISC-V to Rust:
$ rustup target add riscv32imac-unknown-none-elf
Install a RISC-V toolchain. On Ubuntu 20.04, I installed the
gcc-riscv64-unknown-elf package, which actually supports both 32-bit
and 64-bit RISC-V processors.
$ sudo apt-get install gcc-riscv64-unknown-elf
Install a version of dfu-util from May 2020 or later. At the time of this writing, that means installing from source:
$ cd ~/src
$ git clone git://git.code.sf.net/p/dfu-util/dfu-util
$ cd dfu-util
$ ./autogen.sh
$ ./configure
$ make
$ sudo make install
Now we can build the fish program. Building with --release is
necessary, because the debug version of the program is too big to fit
in the Longan Nano's flash!
$ cd ~/src
$ git clone https://github.com/ppelleti/rs-embedded-fish
$ cd rs-embedded-fish
$ cargo build --release
If you installed a different RISC-V toolchain (such as a 32-bit only
one), your objcopy will probably have a different name than mine.
$ riscv64-unknown-elf-objcopy -O binary target/riscv32imac-unknown-none-elf/release/rs-embedded-fish fish.bin
Finally, while holding down the "BOOT" button, plug the Longan Nano into a USB port on the computer. Then upload the program:
$ sudo dfu-util -a 0 -s 0x08000000:leave -D fish.bin
The fish tank should start running automatically, as soon as
dfu-util is done.
The code I have written is made available under the Apache 2.0 license.
The fish images were created by Ferenc Hechler for his AndroFish Android game. According to its F-droid page, AndroFish is also licensed under the Apache 2.0 license.
I've copied a few lines of code from the examples in the longan-nano crate, which is licensed under the ISC License.