I'm spending a bit of time trying to get a bit familiar with the SAM D series. Since I have a SAM D20 Xplained Pro board on the table, I'm reading the D20 data sheet.
I'm looking at the SERCOM module and a term is used/referenced in a lot of places in the data sheet that I can not find any definition of at all: PAD . What is this PAD?
As I read the sheet I can "route" (I believe the sheet uses the term "multiplex") the output of e.g. the SERCOM1 to something called PAD and PAD. Are these names some kind of alias for the pins of the package? Or are they in some mysterious way referring to the digital port(s)? How do I know on what actual pins the SERCOM1 signals occur? How do I know which of Rx and Tx goes to PAD and PAD respectively?
I'm sure there's some wise thought behind this, but I'm not getting it. What am I missing?