57.8.6.7.1 TDRE and RDRF Configuration

The TDRE flag indicates if one or more data can be written in the FIFO depending on the configuration of FLEX_SPI_FMR.TXRDYM/RXRDYM.

As an example, if two data are written each time in FLEX_SPI_TDR, the TXRDYM field can be configured so that the TDRE flag is at ‘1’ only when at least two data can be written in the Transmit FIFO.

Similarly, if four data are read each time in FLEX_SPI_RDR, the RXRDYM field can be configured so that the RDRF flag is at ‘1’ only when at least four unread data are in the Receive FIFO.