16.2.3 Analog Control

The ANSELx register is used to configure the Input mode of an I/O pin to analog. Setting the appropriate ANSELx bit high will cause all digital reads on the pin to be read as ‘0’ and allow analog functions on the pin to operate correctly.

The state of the ANSELx bits has no effect on digital output functions. A pin with TRIS clear and ANSEL set will still operate as a digital output, but the Input mode will be analog. This can cause unexpected behavior when executing READ-MODIFY-WRITE instructions on the affected port.

Important: The ANSELx bits default to the Analog mode after Reset. To use any pins as digital general purpose or peripheral inputs, the corresponding ANSEL bits must be initialized to ‘0’ by user software.