The RA5/MCLR function select attribute allows the function of the MCLR pin to be configured for use as either an external input to MCLR (Master Clear also known as reset) or as an external input to RA5 (PORTA bit 5).NOTE: where the function of the RA5 pin is configurable between RA5 and MCLR, RA5 can only be used by the executing program as an input. It cannot be used as an output.