SW4STM32 and SW4Linux fully supports the STM32MP1 asymmetric multicore Cortex/A7+M4 MPUs

   With System Workbench for Linux, Embedded Linux on the STM32MP1 family of MPUs from ST was never as simple to build and maintain, even for newcomers in the Linux world. And, if you install System Workbench for Linux in System Workbench for STM32 you can seamlessly develop and debug asymmetric applications running partly on Linux, partly on the Cortex-M4.
You can get more information from the ac6-tools website and download (registration required) various documents highlighting:

System Workbench for STM32

You are viewing a reply to ModBus RTU with LWip  

ModBus RTU with LWip



For lwIP, the board you mention does not have any problem; there is an RJ45 connector on the board.

For Modbus-RTU, the problem is that there is no RS485 interface on this board; moreover teh only serial interface signals that can eb accessed on the extension connectors (Arduino-v3 compatible) are Rx/Tx from USART6, but without any modem control signals. So the only possibility is to get an RS485 Arduino shield (like this oneQuestion that will provide such an interface.

Then you will have to look at the various libraries that may allow to implement Modbus-RTU on an STM32 (or on an Arduino, but there will obviously be more adaptations to do); Anyway you will have to tailor them as you will have to use GPIOs to emulate the modem control signals of the USART (needed to drive the RS485 line drivers) that are not available on the Arduino interface.

Hope this helps,

Bernard (Ac6)