SWCU194 March 2023 CC1314R10 , CC1354P10 , CC1354R10 , CC2674P10 , CC2674R10
Write AUX_SPIM:TX8 or AUX_SPIM:TX16 to transfer 8- or 16-bit data between the SPI master and slaves. Data propagates first to the MSB of the I/O. When transfer completes, MOSI stays at value of the LSB.
An ongoing SPI transfer blocks register access:
The Sensor Controller halts when its access gets blocked, which is then exploited to reduce code size and to save power.