Concepts
The General USB Process
How Does the Host Know a Device’s Requirements?
Software – General
Interface
Descriptor
The interface descriptor groups endpoints into functional groups that perform a single feature of the device.
//Sample Standard Interface Descriptor Type
//Definition Fields
Length (9 bytes)
Descriptor Type (INTERFACE)
Interface Number (interface number, zero based, and incremented once for each new interface descriptor.) Alternate Setting (value used to select alternative setting)
Number of Endpoints (number of Endpoints used for this interface)
Interface Class (e.g., HID, mass storage)) Interface Sub Class (subclass Code - assigned by USB Org)
Interface Protocol (Protocol Code assigned by USB Org)
Index (Index of String Descriptor Describing this interface)
