ModbusTCP on STM32+W5500 Test board: STM32F429I-DISCO FreeModbus FreeModbus API: https://www.embedded-experts.at/en/freemodbus/api-documentation/ FreeModbus lib.: https://www.embedded-experts.at/en/freemodbus-downloads/ W5500 ioLibrary: https://github.com/Wiznet/ioLibrary_Driver/