Been looking at the XMEGA-E manual and the data sheet for the ATxmega(8/16/32)E5. There are references to a "Port R". The block diagram on the data sheet, where I first noticed it, seems to associate it with "OSC/CLK CTRL" and there are two pins named PR0 and PR1.
PR0 and PR1 are given functions XTAL1 and XTAL2, TOSC1 and TOSC2, and a small variety of other functions.
Can someone describe what this two-pin "port" is all about?