19.4 TRISx - Direction Control

The TRISx register controls the PORTx pin output drivers, even when the pins are being used as analog inputs. The user must ensure the bits in the TRISx register are set when using the pins as analog inputs. I/O pins configured as analog inputs always read ‘0’.

Setting a TRISx bit (TRISx = 1) will make the corresponding PORTx pin an input (i.e., disable the output driver). Clearing a TRISx bit (TRISx = 0) will make the corresponding PORTx pin an output (i.e., it enables output driver and puts the contents of the output latch on the selected pin).