6.4 Revision 3
Revision 3 and previous revisions use ATSAML21J18A-AUTES as the main device, revision 3 is the initially released revision.
The top level order code of the SAM L21 Xplained Pro evaluation kit is ATSAML21-XPRO for revision 3.
The extra crystal footprint connected to PA14 and PA15 described in Crystals is not present on this revision.
The overview picture in Figure 1-1 is not applicable for revision 3, see the figure below instead.