The RXD, CTS (Clear To Send, active low), RTS (Request To Send, active low), and TXD signals associated with UARTE are mapped to physical pins according to the configuration specified in the PSEL.n registers.
These registers and their configurations are only used when UARTE is enabled, and retained while the device is in System ON mode. The PSEL.n registers can be configured only when UARTE is disabled.
To ensure correct behavior when in System OFF mode, the pins must be configured in the GPIO peripheral as described in the following table.
Only one peripheral can be assigned to drive a particular GPIO pin at a time. Failing to do so may result in unpredictable behavior.
| UARTE signal | UARTE pin | Direction | Output value |
|---|---|---|---|
| RXD | As specified in PSEL.RXD | Input | Not applicable |
| CTS | As specified in PSEL.CTS | Input | Not applicable |
| RTS | As specified in PSEL.RTS | Output | 1 |
| TXD | As specified in PSEL.TXD | Output | 1 |