Mikroe MCU CARD for STM32 STM32F746ZG allows installation and replacement of the microcontroller unit (MCU) on a development board. The new MCU Card standard ensures compatibility between the development board and supported MCUs, regardless of pin number and compatibility. MCU Cards are equipped with two 168-pin mezzanine connectors, allowing them to support even MCUs with extremely high pin count. The design allows for usage with the plug & play concept of the Click board™ line.