The Modbus server was previously unstable, leading to intermittent CRC errors when polled by a master. This was caused by the main thread exiting after initialization, which created timing and race condition issues for the interrupt-driven Modbus stack.
This fix ensures the main thread continues to run in a low-power sleep loop (). This provides a stable context for the Modbus server, resolving the CRC errors and ensuring reliable communication.
- Add a basic Modbus RTU server implementation based on Zephyr samples.
- Configure usart1 for Modbus via a board overlay.
- The server initializes and runs, but polling with mbpoll results in a timeout.
- This commit captures a functional but non-working state for further debugging.