SWCU194 March 2023 CC1314R10 , CC1354P10 , CC1354R10 , CC2674P10 , CC2674R10
The CC13x4x10 and CC26x4x10 devices provide an interface to connect to a µDMA controller. Figure 22-3 shows the interface between the µDMA and UART. This interface contains four DMA requests as outputs (RX Single, RX Burst, TX Single, and TX Burst). The DMA interface also has two DMA request clears as inputs (for clearing TX and RX DMA requests). Each DMA request signal remains asserted until the relevant DMA clear signal is asserted.
The burst transfer and single transfer request signals are not mutually exclusive, and both can be asserted at the same time. For example, when there is more data than the trigger level in the receive FIFO, the burst transfer request and the single transfer request are asserted.
The single and burst requests cannot be masked separately by the UART module and if corresponding DMA (RX or TX) is enabled, both of these requests are sent to the DMA. The DMA configuration selects either single or burst request as the trigger. All request signals are deasserted if the UART is disabled or if the relevant DMA enable bit (TXDMAE or RXDMAE) in the DMA Control Register (UART:DMACTL) is cleared.