Expansion boards and daughter cards are supplementary development platforms designed to extend the capabilities of base development boards such as microcontrollers (MCUs), FPGAs, or DSP boards. These boards connect directly to the main board via standardized headers, sockets, or connectors and provide additional functionalities such as extra input/output ports, communication interfaces, sensors, memory modules, or specialized processing units. They allow engineers and designers to customize and enhance their development environment without redesigning the primary board.