SPRUHM9H October 2014 – May 2024 TMS320F28075 , TMS320F28075-Q1 , TMS320F28076
The SPI protocol is a master-slave configuration with one master device and one or more slave devices. The interface consists of the following four signals:
A typical SPI interface with a single slave device is shown in Figure 20-36.
The master device controls the flow of communication by providing shift-clock and slave-enable signals. The slave-enable signal is an optional active-low signal that enables the serial data input and output of the slave device (device not sending out the clock).
In the absence of a dedicated slave-enable signal, communication between the master and slave is determined by the presence or absence of an active shift-clock. When the McBSP is operating in SPI master mode and the SPISTE signal is not used by the SPI slave port, the slave device must remain enabled at all times, and multiple slaves cannot be used.