Many people are confused by the difference between a "Crystal" and a "Crystal Oscillator".
There was an illustrated post here explaining the difference (I think I wrote it):
https://e2e.ti.com/support/microcontrollers/stellaris_arm/f/471/p/135114/555988#555988
but that link no longer works.
Is there any way to retrieve that post?
(I've tried the Wayback machine - no luck).
I've also tried searching here, but the terms are too common.
The post is referenced here:
https://www.avrfreaks.net/s/topic/a5C3l000000UYYQEA4/t146620?comment=P-1401006