There are many reasons to use serial protocols in embedded systems: simplicity, low pin count, and the ability to set up a network of simple devices to implement a complex functionality. Focusing on the Serial Peripheral Interface (SPI), this paper explores the
reasons to test and debug an SPI port. It then describes and compares the tools available on the market for test and debug, from general purpose oscilloscopes to specialized PC-based SPI
exercisers and analyzers.