How to configure UART Rx function if pin has Uart Rx and nRESET functions?

[a_ziliu]

Take MS51DA9AE for example. After power-on, P2.0 can configure as the external reset pin or an input-only pin. By default, P2.0 is configured as external reset pin.
Only when P2.0 is configured as an input-only pin can user select alternate function. Take UART Rx function for example. Please follow the steps below.
Program RPD (CONFIG0.2) as 0 by ICP tool. The purpose is to configure P2.0 as input pin available.

Remove pull-up resistor from reset circuit. The purpose is to avoid that IO can’t drive the signal low by external sources with pull-up resistor.