49.5.6 Peripheral DMA Controller (PDC)
Both the receiver and the transmitter of the UART are connected to a PDC.
The PDC channels are programmed via registers that are mapped within the UART user interface from the offset 0x100. The status bits are reported in UART_SR and generate an interrupt.
The RXRDY bit triggers the PDC channel data transfer of the receiver. This results in a read of the data in UART_RHR. TXRDY triggers the PDC channel data transfer of the transmitter. This results in a write of data in UART_THR.
