This is a fork of the FreeModbus protocol stack, extended with ports for:
- ADuc702x processors
- STM32 processors using CMake build system
FreeModbus is a Modbus ASCII/RTU and Modbus TCP implementation for embedded systems. It provides an implementation of the Modbus Application Protocol v1.1a and supports both the RT 6268 U and ASCII transmission modes as defined in the Modbus over serial line specification 1.0.
The STM32 CMake port is located in the demo/STM32_CMAKE directory and provides:
- A generic implementation that can target multiple STM32 families
- HAL-based peripheral access for portability
- Integration with CMake build systems
- Simple demo application
- Support for the STM32G4 family (tested on Nucleo-G431RB)
Complete documentation of the original FreeModbus implementation can be found in the doc/html directory.
For information specific to the STM32 CMake port, refer to the demo/STM32_CMAKE/README.md file.
FreeModbus uses a multi-license approach:
- Core Protocol Stack (in
modbus/directory): BSD License - Port Implementations (in
demo/*/port/directories): Generally LGPL License - Demo Applications (in
demo/*/directories): Generally GPL License
This licensing structure allows:
- Using the core protocol stack in both open-source and proprietary applications (BSD)
- Using the port implementations in proprietary applications with some restrictions (LGPL)
- Using the demo applications only in GPL-compatible projects (GPL)
Always check the license header in individual source files for specific licensing terms.