The second page of this document provides some details in diagrams. https://docs.broadcom.com/doc/1211168563383 https://docs.broadcom.com/doc/1211168563383 I

The second page of this document provides some details in diagrams. https://docs.broadcom.com/doc/1211168563383 https://docs.broadcom.com/doc/1211168563383 I presume it wakes up the chipset to do most of its work remotely.