TCP, USART and USB-CDC Modbus RTU Master and Slave library for STM32 microcontrollers based on Cube HAL and FreeRTOS.
Includes multiple examples for popular development boards including BluePill, NUCLEO-64, NUCLEO-144 and Discovery Boards (Cortex-M3/M4/M7).
This is a port of the Modbus library for Arduino: https://github.com/smarmengol/Modbus-Master-Slave-for-Arduino
Video demo for STM32F4-discovery board and TouchGFX: https://youtu.be/XDCQvu0LirY
NEW Script examples to test the library based on Pymodbus
NEW TCP slave (server) multi-client with configurable auto-aging algorithm for management of TCP connections
Traditional Chinese: 繁體中文
- Portable to any STM32 MCU supported by ST Cube HAL.
- Portable to other Microcontrollers, like the Raspberry PI Pico, requiring little engineering effort.
- Multithread-safe implementation based on FreeRTOS.
- Multiple instances of Modbus (Master and/or Slave) can run concurrently in the same MCU, only limited by the number of available UART/USART of the MCU.
- RS232 and RS485 compatible.
- USART DMA support for high baudrates with idle-line detection.
- USB-CDC RTU master and Slave support for F103 Bluepill board.
- TCP master and slave support with examples for F429 and H743 MCUs
├── LICENSE
├── README.md
├── Examples
├── ModbusBluepill --> STM32F103C8 USART Slave
├── ModbusBluepillUSB --> STM32F103C8 USART + USB-CDC Master and Slave
├── ModbusF103 --> NUCLEO-F103RB Modbus Master and Slave
├── ModbusF429 --> NUCLEO-F429ZI Modbus Slave
├── ModbusF429TCP --> NUCLEO-F429ZI Modbus TCP
├── ModbusF429DMA --> NUCLEO-F429ZI Modbus RTU DMA master and slave
├── ModbusL152DMA --> NUCLEO-L152RE Modbus RTU DMA slave
├── ModbusH743 --> NUCLEO-H743ZI Modbus Slave
├── ModbusH743TCP --> NUCLEO-H743ZI Modbus TCP
├── ModbusF303 --> NUCLEO-F303RE Modbus Slave
├── ModbusSTM32F4-discovery --> STM32F4-discovery TouchGFX + Modbus Master
├── ModbusWB55DMA --> P-NUCLEO-WB55 Modbus RTU DMA slave with RS485
├── ModbusG070 --> NUCLEO-G070RB Modbus Slave
├── ModbusF030 --> STM32F030RCT6 USART Slave
├── ModbusH503 --> STM32H503RBTx USART Slave
├── ModbusG431 --> NUCLEO-G431KB USART Slave
├── Script
├── *.ipynb --> various master and slave Jupyter notebooks for testing
├── MODBUS-LIB --> Library Folder
├── Inc
│ └── Modbus.h
├── Config
│ └── ModbusConfigTemplate.h --> Configuration Template
└── Src
├── Modbus.c
└── UARTCallback.c
Examples provided for STM32CubeIDE Version: 1.8.0 https://www.st.com/en/development-tools/stm32cubeide.html.
- Import the examples in the STM32Cube IDE from the system folder
- Connect your NUCLEO board
- Compile and start your debugging session!
- If you need to adjust the Baud rate or any other parameter use the Cube-MX assistant (recommended). If you change the USART port you need to enable the interrupts for the selected USART. Check UARTCallback.c for more details.
-
The standard interrupt mode for Modbus RTU USART is suitable for 115200 bps or lower baud rates. For Higher baud rates---tested up to 2 Mbps---it is recommended to use the DMA mode. Check the corresponding examples. It will require extra configurations for the DMA channels in the Cube HAL.
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The USB-CDC example supports only the Bluepill development board. It has not been validated with other development boards. To use this example, you need to activate USB-CDC in your ModbusConfig.h file.
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The TCP examples have been validated with NUCLEO F429ZI and H743ZI. To use these examples, you need to activate TCP in your ModbusConfig.h file.
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The HAL implementation for LWIP TCP of the CubeMX generates code that might not work if the cable is not connected from the very beginning. This is a known issue that can be solved manually changing the generated code as detailed here: https://community.st.com/s/question/0D50X0000CDolzDSQR/ethernet-does-not-work-if-uc-starts-with-the-cable-disconnected
Check the TCP example for the NUCLEO F429, which includes the manual modifications.
- Create a new project in STM32Cube IDE for your MCU
- Enable FreeRTOS CMSIS_V2 in the middleware section of Cube-MX
- Configure a USART and activate the global interrupt
- If you are using the DMA mode for USART, configure the DMA requests for RX and TX
- Configure the
Preemption priorityof USART interrupt to a lower priority (5 or a higher number for a standard configuration) than your FreeRTOS scheduler. This parameter is changed in the NVIC configuration pane. - Import the Modbus library folder (MODBUS-LIB) using drag-and-drop from your host operating system to your STM32Cube IDE project
- When asked, choose link folders and files
- Update the include paths in the project's properties to include the
Incfolder of MODBUS-LIB folder - Create a ModbusConfig.h using the ModbusConfigTemplate.h and add it to your project in your include path
- Instantiate a new global modbusHandler_t and follow the examples provided in the repository
Note:If your project uses the USART interrupt service for other purposes you have to modify the UARTCallback.c file accordingly
Linux/Windows: https://github.com/riptideio/pymodbus
Linux: https://launchpad.net/~js-reynaud/+archive/ubuntu/qmodbus
Windows: https://sourceforge.net/projects/qmodbus/
Linux: https://sourceforge.net/projects/pymodslave/
Windows: https://sourceforge.net/projects/modrssim2/
- Implement isolated memory spaces for coils, inputs and holding registers.
- Implement wrapper functions for Master function codes. Currently, telegrams are defined manually.
- Improve function documentation
MODBUS TCP implementation improvement to support multiple clients and TCP session management(10/24/2021)Improve the queue for data reception; the current method is too heavy it should be replaced with a simple buffer, a stream, or another FreeRTOS primitive.Solved Queue replaced by a Ring Buffer (03/19/2021)Test with Rs485 transceivers (implemented but not tested)Verified with MAX485 transceivers (01/03/2021)MODBUS TCP implementation(28/04/2021)
