Short PDF excerpt concerning the Atmel AT91SAM family of ARM-based microcontrollers, apparently pages 7 and 8 taken from an issue of a publication or document, judging by the name. At under 80 KB it is a fragment rather than a full datasheet, so expect only a narrow slice of information. Technicians working on boards built around AT91SAM parts can use it for quick reference, but pinouts, electrical limits and register details should be confirmed against the complete Microchip/Atmel datasheet for the exact part number marked on the chip.
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.