canbus sensor board

A simple board optimized for handling I²C-connected sensors and communicate the status over CAN bus.

This repo contains both the PCB design files, as well as Rust-based firmware.

To flash and run the firmware:

Install Rust. Using rustup is very strongly encouraged as it automates installation of cross compilation files and such.
Install probe-rs, a CLI for connecting to debug probes, with cargo install probe-rs.
Install flip-link, a meta-linker that puts the stack at the end of embedded memory, using cargo install flip-link.
Optionally update the DEFAULT_CAN_ID variable in src/config.rs if you want to change the CAN bus ID of the board without having to send it a command later.

Flash using a debug probe (easiest):

Connect the PCB to your computer using a SWD-based debug probe, for example a ST-Link v2 clone can be found super cheaply online, usually around $3 USD. You can either solder wires to the provided pads (see PCB design files for pin assignments) or else use a TagConnect TC2030-NL cable, which has pogo pins matching the pads on the board, and can be bought with adapter wires that are compatible with an ST-Link module.
Run cargo flash --release --chip STM32F103C8 --connect-under-reset to flash to the board or run cargo run to flash the firmware using a debug build, start it, and stream debug logs to the terminal using the defmt RTT protocol. (You can of course also do any combination, e.g. cargo run --release etc)

Flash using CAN bus (more tricky perhaps):

Install can-prog, see the link for additional details.
Connect the PCB to a CAN bus.
Using some wires, first short the 3.3V and BOOT pads, and while still shorting the pads, also short the ~RST and GND pads. This should put the board in DFU mode.
Build the firmware in release mode with cargo build --release

Convert the generated ELF file to a raw .bin file with:

arm-none-eabi-objcopy -O binary target/thumbv7m-none-eabi/release/canbus-sensor-board image.bin

Run the command canprog -f bin stm32 write image.bin -a 0x08000000 or similar. You might need to run canprog stm32 erase and such depending on the state of the firmware.

dflemstr / canbus-sensor-board