57.7.11.1 Overview

The USART includes two FIFOs which can be enabled/disabled using FLEX_US_CR.FIFOEN/FIFODIS. Both the transmitter and the receiver must be disabled before enabling or disabling the FIFOs, using the FLEX_US_CR.TXDIS/RXDIS bits.

Writing FLEX_US_CR.FIFOEN to ‘1’ enables a 16-data Transmit FIFO and a 16-data Receive FIFO.

When the FIFO is enabled, it is possible to write or to read single data (5-bit to 9-bit data) or multiple data (5-bit to 8-bit data) in the same access to FLEX_US_THR/RHR. See FIFO Single Data Access and FIFO Multiple Data Access.