SWRU543B January 2019 – June 2025 CC3230S , CC3230SF , CC3235MODS , CC3235MODSF , CC3235S , CC3235SF
This section describes the supported data accesses (read or write) to and from the data receiver registers SPI_RX and data transmitter registers SPI_TX.
The SPI supports only one SPI word per register (receiver or transmitter) and does not support successive 8-bit or 16-bit accesses for a single SPI word. The SPI word received is always right-justified on the LSB of the 32-bit SPI_RX register, and the SPI word to transmit is always right-justified on the LSB of the 32-bit SPI_TX register. The bits above SPI word length are ignored, and the content of the data registers is not reset between the SPI data transfers. The user is responsible for the coherence between the number of bits of the SPI word, the number of bits of the access, and the enabled byte. Only aligned accesses are supported. In master mode, data must not be written in the transmit register when the channel is disabled.