what is a motherboard?

Each motherboard comprises a microcontroller, including a central processing unit and some internal hardware and functional components. In order to provide an easy to use basis for the development and operation of a variety of embedded projects, further external components like a crystal, a power supply, general status LEDs, and connectors for programming/debugging purposes or for hardware enhancements are added. The connection between a motherboard and any of the modules is established by simply plugging into the provided port connectors (plus flexible ribbon cables).