57.8.6.1 Overview
The SPI includes two FIFOs which can be enabled/disabled using the FLEX_SPI_CR.FIFOEN/FIFODIS. The SPI module must be disabled before enabling or disabling the SPI FIFOs (FLEX_SPI_CR.SPIDIS).
Writing FLEX_SPI_CR.FIFOEN to ‘1’ enables a 16-data Transmit FIFO and a 16-data Receive FIFO.
The size of a data (8-bit to 16-bit) is determined by the value configured in FLEX_SPI_CSRx.BITS.
It is possible to write or to read single or multiple data in the same access to FLEX_SPI_TDR/RDR. See SPI Single Data Access and SPI Multiple Data Access.