LRR-TUM-Logo Department of Informatics
Technische Universität München
Informatik X: Rechnertechnik und Rechnerorganisation / Parallelrechnerarchitektur
Prof. Dr. Arndt Bode , Prof. Dr. Hans Michael Gerndt
 Home  | Addresses  | Staff  | Research  | Lectures 
next up previous contents index
Next: Standard Descriptors Up: The Universal Serial Bus Previous: Data Flow Types   Contents   Index

Enumeration and Device Descriptors

Whenever a USB device is attached to the bus it will be enumerated by the USB subsystem - i.e an unique device number (1-127) is assigned and then the device descriptor is read. Such a desciptor is a data structure which contains information about the device and its properties. The USB standard defines a hierarchy of descriptors (see figure 2).

Figure 2: USB Descriptor Hierarchy
\includegraphics [width=\linewidth]{descr}


Detlef Fliegl
(none) Webmaster