STM32 Nucleo Expansion Boards STMicroelectronics STM32 X-Nucleo Expansion Boards carry all the required components to evaluate ST devices to be used together with an STM32 MCU and to build STM32-based applications. The Expansion Boards are equipped with standardized interconnections, like an Arduino Uno R3 connector, or a Morpho connector for a higher level of connectivity. Each Expansion Board is supported by STM32-based software modules. The combination of STM32 Nucleo Boards and Expansion Boards is a unified scalable approach with unlimited possibilities for application development, prototyping, or product evaluation.