Port 3 Alternate Functions

Port 3 multi functions are

RXD     it is used for serial input port
TXD      it is used for serial output port
INT0    used for external interrupt 0
INT1   used for external interrupt 1
T0      Timer 0 external input
T1      Timer 1 external input
WR  external data memory write strobe
RD     external data memory Read strobe