@westfw, nice job on the spreadsheet. It looks like you corrected PA12/13 COM (O23:24) as per the docs. N23 and N24 should be swapped as well since TX is only available on pad 0.
Has anyone verified that PA12/13 SERCOM4 pads were actually swapped or was this a documentation error? That's a pretty good OOPS if they physically swapped since you would have to make board level changes if using SERCOM4.
@westfw, did you do a similar spreadsheet for the D21? It would be nice to compare the D21 and D51 via spreadsheet.
Robin