SWCU195A December 2024 – May 2025 CC2744R7-Q1 , CC2745P10-Q1 , CC2745R10-Q1 , CC2745R7-Q1 , CC2755R10
The SPI includes a feature to automatically insert a 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 the 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 via 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 the CRC is done.
Similarly, after reading all the received data through the SPI.RXDATA register, the 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.