Designing my Own RaspBerry clone : decoupling capacitor.


I am starting my hand on building my own Raspberry Clone. I have built Arduino clones, before Arduino was a thing, and you had to use DIP package ATMEL controllers.
Now I want to try my hand at ARM based CPUs in contrast to MCUs such as the typical ATMEL products (e.g. ATMEGA xxxx).

This is my first time with ARM, so please bear with me.

I have chosen the Sitara family of processors, AM437x series.

I am using the open source BeagleBones project as my start point. I know that the projct is NOT a reference design, and only community support is allowed.

I as seeing in the Datasheet for AM 335x (the one used by BeagleBones) as well as for AM 437x, that the decoupling capacitor can be 10.08 µF . See here, page 93.

But the BeagleBone schematic uses > 20.13 µF capacitor. See page 5.

Why the difference ? How is the correct value of the capacitor determined?

Thank you.