ADCON1 configures analog or digital operation on this device.

As a note, I was really confused at first when I went to get the datasheet. It was only 54 pages! Well it seems they have a big note at the beginning explaining this is just the differences between this and another chip. Further they want me to use that datasheet except for the parts listed in the 54 page sheet. Anyway, the A/D stuff is in the "short sheet" So I suspect you are reading the other one as stated by you it is 380 pages.