I want to configure the UART to support a 1 wire bidrectional interface. Can I configure the TX port as open drain?
It is possible to configure the UART TX pin to be open drain. If you are using configurator, it will issue a warning for this, but the warning can be ignored. If you are not using configurator, you can set the TX pin to be open drain by clearing bit 4 of P0MDOUT. When using the UART this way, it is important to ensure that the two devices to not transmit at the same time.