35.1 UART I/O Pin Configuration
The RX input pin is selected with the UxRPPS register. The TX output pin is selected with each pin’s RxyPPS register. When the TRIS control for the pin corresponding to the TX output is cleared, the UART will control the logic level on the TX pin. Changing the TXPOL bit in UxCON2 will immediately change the TX pin logic level, regardless of the value of EN or TXEN.