Here are some tips and tricks to keep in mind when working with Xbox 360 controller schematics:
: Pair the schematic PDF with a multimeter continuity test on your own controller. Trace a button from its physical pad to a pin on the MCU – you’ll learn more in an hour than reading theory for a week.
This is the tricky part. Microsoft considers these documents proprietary, so they aren't on official support sites. However, the hardware community has preserved them.
It is critical to note that there are two primary schematic variants: Xbox 360 Controller Schematic Pdf