Waking PIC's Up From Sleep
This is often just an IRQ for pins RB7:4 not the whole port
No this won't work!!!! The UART needs the osc to create its internal baud timer. If you need to wake up on RX connect to the pin to an INT pin also, or for programamble peripheral pins you can often assign both UART RX and INT1 etc to the same RP# pin.