Rust Modbus context example with stm32 (stm32f103c8t6) & RS485

Very simple example of Modbus context on stm32 via RS485/RTU.

Hardware

• stm32f103c8t6

• UART TTL to RS485 (MAX485)

• ST-LINK/V2 (for flashing)

• any USB RS485 whistle (for testing from PC)

Wiring

Software

• any Modbus client (e.g. https://github.com/favalex/modbus-cli for tests)

Libraries

• https://github.com/stm32-rs/stm32f1xx-hal/ for STM32F1 HAL

• https://github.com/alttch/rmodbus for Modbus

Flashing

cargo install cargo-flash # if not installed yed
cargo flash --chip stm32f103C8 --release

What can it do

Just the demo. You can read/write Modbus context with any Modbus/RTU client, get/set any Modbus registers.

Input registers 0 and 1 contain processed frame counter (big-endian u32).

Rmodbus used with "smallcontext" feature, so only registers 0-999 (all types) are accessible.

Enjoy!