Modbus Communication with Limited UART Resources
Modbus RTU communication implemented over RS485 without dedicated RTS/CTS handshake lines, plus a dedicated C# test tool.
- Implemented reliable Modbus/RS485 direction and timing control without RTS/CTS lines
- Built a separate C# tool to test and validate Modbus parameters
- Delivered a production-tested register map and exception handling
- Technologies: Modbus, RS485, UART, C, C#
Context
An existing controller system needed Modbus communication, although the available UART hardware only provided limited signals.
My Role
I developed the Modbus communication under the constraint that no RTS/CTS lines were available.
Technical Challenge
Modbus over RS485 requires reliable direction and timing control. Without additional handshake lines, communication had to be implemented and tested especially carefully.
Solution
The firmware and communication logic were designed so that Modbus could operate reliably despite limited UART TX/RX availability. A separate C# test tool was also created to verify Modbus parameters.
Impact
The project made an industrial interface possible on existing hardware and improved the testability of the communication function.
Technologies
Modbus, RS485, UART, C, C#
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