Rusty clock 
An alarm clock with environment stats in pure bare metal embedded rust.
Description
This alarm clock is programed in bare metal rust (no OS). It features pressure, temperature, humidity, monophonic alarm on a e-paper display.
Hardware
The hardware used in this project is
- a blue pill board featuring a STM32F103C8 microcontroller (20KiB RAM, 64 KiB flash, ARM Cortex M3 @72MHz);
- a 2.9" WaveShare e-paper display (296x128 black or white pixels);
- a BME280 sensor for temperature, humidity and pressure on a I2C compatible PCB (VIN, GND, SCL and SDA pins);
- a passive buzzer driven by PWM;
- 4 16mm normally open push buttons (cancel, previous, next, OK);
- a 3D printed case;
- USB power plug;
- micro USB cable;
- a CR20xx coin battery (optional);
- wires (I use single core wires) and soldering set;
- 4 2mm wood screws.
You also need a ST-Link v2 to flash and debug.
Everything can be purchased on Aliexpress. Budget is around US $35 without the 3D printed case and soldering set.
Wiring
Everything is plugged directly to the blue pill board.
E-paper display to blue pill board:
- BUSY -> A10
- RST -> A9
- DC -> A8
- CS -> B12
- CLK -> B13
- DIN -> B15
- GND -> G
- VCC -> 3.3
BME280 to blue pill board:
- VIN -> 3.3
- GND -> G
- SCL -> B6
- SDA -> B7
Buttons are connected to the blue pill board between G and
- A6 for cancel
- A7 for previous
- B0 for next
- B1 for OK
Passive buzzer is connected to the blue pill board between G and A0.
Coin battery to blue pill board:
- (-) -> G
- (+) -> VB
Plug the micro USB connector of the blue pill board to a USB power supply (or a computer).
Compiling and flashing
For compiling and flashing, please refer to the blue pill quickstart.
Basically:
curl https://sh.rustup.rs -sSf | sh
rustup target add thumbv7m-none-eabi
sudo apt-get install gdb-arm-none-eabi openocd
cd rusty-clock
# connect ST-Link v2 to the blue pill and the computer
# ./openocd.sh in another terminal
cargo run --release