SWCU194 March 2023 CC1314R10 , CC1354P10 , CC1354R10 , CC2674P10 , CC2674R10
The Motorola SPI is a 4-wire interface where the SPIn_CS signal behaves as a slave select. In the 3-wire interface the SPIn_CS is unused, and behaves like this signal is always asserted and SPI is always selected. The selection between the 3-wire and 4-wire Motorola SPI Frame Format can be made within the SPI:CTL0.FRF field. The main feature of the Motorola SPI format is that the inactive state and phase of the SPIn_CLK signal can be programmed through the SPO and SPH bits in the SPI:CTL0 control register.