The SPI (Serial Peripheral Interface) bus is one of the commonly used protocols to connect sensors and many other devices to microcontrollers. The SPI bus is a master-slave-type bus protocol. In this protocol, one device (the microcontroller) is designated as the master, and one or more other devices (usually sensors) are designated as slaves. In a minimum bus configuration there is one master and only one slave. The master establishes communication with the slaves and controls all the activity on the bus. This chapter presents the Nucleo-F411RE development board SPI bus GPIO pins. An SPI bus-based project is given in the chapter using a digital-to-analog converter chip.