Datasheet in PDF form, 246 KB, named only by the document number doc6272, so the file name gives no hint of the exact component. Such numbering matches the literature codes Atmel assigned to its datasheets and application notes, and the device name appears on the first page. Once opened it serves for checking pin functions, absolute maximum ratings, supply voltages and package outlines. Always match the part number and package in the document to the chip on the board before using the information during repair.
The button opens the matching file on RM Schematics, or a source page if it is not catalogued there yet. The original attachment is from @datasheet. Enginerys does not host this file.
How to open a .pdf file
The standard format for schematics, block diagrams, power-sequence charts and service manuals.