SPRUI30H November 2015 – May 2024 DRA745 , DRA746 , DRA750 , DRA756
The FIFO is accessed by reading and writing the UARTi.UART_RHR and UARTi.UART_THR registers. Parameters are controlled using the FIFO control register (UARTi.UART_FCR) and supplementary control register (UARTi.UART_SCR). Reading the UARTi.UART_SSR[0] TX_FIFO_FULL bit at 1 means the FIFO is full.
The UARTi.UART_TLR register controls the FIFO trigger level, which enables DMA and interrupt generation. After reset, transmit (TX) and receive (RX) FIFOs are disabled; thus, the trigger level is the default value of 1 byte. Figure 24-59 shows the FIFO management registers.
Data in the UARTi.UART_RHR register is not overwritten when an overflow occurs.
The UARTi.UART_SFLSR, UARTi.UART_SFREGL, and UARTi.UART_SFREGH status registers are used in IrDA mode only. For information about their use, see Section 24.3.4.8.2.3, IrDA Data Formatting.
Bits UARTI.UART_FCR[2] TX_FIFO_CLEAR and UARTI.UART_FCR[1] RX_FIFO_CLEAR are automatically cleared by hardware after 4* UARTi_ICLK + 5* UARTi_FCLK clock cycles. This delay is needed to finish the resetting of the corresponding FIFO and DMA control registers.