1 Each term should be used in one and only one way throughout the dissertation.  The easiest way to avoid a long series of definitions is to include a statement: ``the terminology used throughout this document follows that given in [CITATION].'' Then, only define exceptions.
Serial Peripheral Interface Bus. The Serial Peripheral Interface bus (SPI) is a synchronous serial communication interface specification used for short distance communication, primarily in embedded systems. The interface was developed by Motorola in the late 1980s and has become a de facto standard. Typical applications include Secure Digital cards and liquid crystal displays.
Techopedia explains Universal Serial Bus (USB) A Universal Serial Bus (USB) is basically a newer port that is used as a common interface to connect several different types of devices such as keyboards, printers, media devices, cameras, scanners, and mice. It is designed for easy installation, faster transfer rates, higher quality cabling and hot swapping.