SWCU193A April 2023 – August 2024 CC2340R2 , CC2340R5 , CC2340R5-Q1
The SPI includes a feature to automatically insert the CRC when the TX FIFO underflows. This feature can be enabled by the SPI.CTL0[14] AUTOCRC bit.
When this bit is set, the SPI module loads the calculated CRC checksum into the TX FIFO after all bytes are transmitted when TXFIFO underflow is signaled. This causes the CRC to be transmitted out automatically at the end of the data block.
There is no need for software to read and load this CRC value into the FIFO through a TXDATA register write.
Software must read the SPI.TXCRC[31] AUTOINS bit to reinitialize the TX CRC engine to a seed of all ones after the transfer of data and CRC is done.
Similarly, after reading all the received data through the SPI.RXDATA register, software must read the SPI.RXCRC register to obtain the CRC value and auto-initialize the RX CRC engine to a seed value of all ones.