RTFM page 3: TRISx Registers The TRISx register control bits
determine whether each pin associated with the I/O port is an input
or an output. If the TRIS bit for an I/O pin is a ‘1’, then the pin
is an input. If the TRIS bit for an I/O pin is a ‘0’, then the pin
is configured as an output. An easy way to remember this is that a ‘1’ looks like an I
(Input) and a ‘0’ looks like an O (Output) -->24E_33E_10_Ports_C.pdf