UARTE implements EasyDMA for reading and writing to and from the RAM.
If the TXD.PTR and the RXD.PTR are not pointing to the Data RAM region, an EasyDMA transfer may result in a HardFault or RAM corruption. See Memory for more information about the different memory regions.
The RXD.PTR, TXD.PTR, RXD.MAXCNT, and TXD.MAXCNT registers are double-buffered. They can be updated and prepared for the next reception or transmission immediately after having received the RXSTARTED or TXSTARTED event.
The ENDRX and ENDTX events indicate that the EasyDMA is finished accessing the RX or TX buffer in RAM.