embedded-life

embedded-life is Conway's Game Of Life rendered on an OLED display, and built for an ARM Cortex-M (STM32F103), Raspberry Pi and a SDL-based display simulator. It demonstrates using the power of Rust embedded-hal abstraction to write portable code.

For an in-depth discussion, please see the detailed article on my blog. This document will focus on instructions for building and running the code only.

Build

Install build dependencies

The simulator app requires SDL2.
The ARM targets needs the linker from ARM GCC and binutils.

This will work for Ubuntu/Debian/Mint (other platforms will have similar packages):

$ sudo apt-get -y install libsdl2-dev gcc-arm-linux-gnueabihf binutils-arm-none-eabi

Depending on what programming hardware you have, you may also need openocd, stlink-tools or stm32flash. I'm using stm32flash with a FTDI FT232RL (3.3v USB UART):

$ sudo apt-get -y install stm32flash

You'll also need rustup (get it here).

From this point on everything is in Rust-land:

$ rustup target add armv7-unknown-linux-gnueabihf
$ rustup target add thumbv7m-none-eabi

Build all the targets

Finally, run the build script (this is required because cargo's workspaces don't work well with multiple architectures):

$ ./build.sh

Running

The simulator

Run:

$ ./target/release/life-simulator

ARM Cortex-M (maple mini)

If you have a maple mini clone, and an SSD1306 OLED display, you can wire them up as follows:

ssd1306 SDA to mini pin 15
ssd1306 SCL to mini pin 16
ssd1306 VCC to mini VCC
ssd1306 GND to mini GND
mini BUT to mini VCC
mini pin 2 (boot) to mini GND
mini GND to UART GND
mini VIN to UART 3.3V
mini pin 25 (rx1) to UART TXD
mini pin 24 (tx1) to UART RXD

The script in life-maple-mini/build-and-flash.sh takes a USB serial device file argument, and uses stm32flash to program the STM32 (remember to press the reset button first):

$ ./build-and-flash.sh /dev/ttyUSB0 
<snip>
    Finished release [optimized] target(s) in 24.41s
stm32flash 0.5

http://stm32flash.sourceforge.net/

Using Parser : Intel HEX
Interface serial_posix: 57600 8E1
Version      : 0x22
Option 1     : 0x00
Option 2     : 0x00
Device ID    : 0x0410 (STM32F10xxx Medium-density)
- RAM        : 20KiB  (512b reserved by bootloader)
- Flash      : 128KiB (size first sector: 4x1024)
- Option RAM : 16b
- System RAM : 2KiB
Write to memory
Erasing memory
Wrote address 0x080056e8 (100.00%) Done.

Starting execution at address 0x08000000... done.

The Raspberry Pi

To try this on a Raspberry Pi, wire the SSD1306 OLED display to one of the I2C busses. The I2C device file is hard coded (to /dev/i2c-0) in life-raspi/src/main.rs. If you're not using the first I2C bus, edit as required. Note that depending on the Pi model, you may also need to edit the /boot/config.txt file (and reboot) to enable I2C.

Running the code is as simple as copying target/armv7-unknown-linux-gnueabihf/release/life-raspi to the Pi (scp or transfer by USB drive) and then running it with ./life-raspi.

License and attribution

embedded-life is largely derivative of James Waples' embedded graphics crates, so it is reproduced under the same license (Apache 2.0) - see LICENSE.

The Rust implementation of Game Of Life is loosely based on the version at Rosetta code. For details please see the notes in life/src/lib.rs.

simeonmiteff / embedded-life