Part II: Controller
Chapter 5, The Physical Layer, describes how devices communicate wirelessly with one another.
Chapter 6, Direct Test Mode, highlights the Direct Test Mode and its role in performing low-cost, time-efficient testing of the radio.
Chapter 7, The Link Layer, introduces the lowest layers of protocol that describe packets, advertising, and how to create a connection.
Chapter 8, The Host/Controller Interface, describes the interface that hosts can use to talk with a controller and get it to do useful things.