Teledyne LeCroy USB Chief - Users Manual - Manual (Page 73)

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Chief User’s Manual CATC Version 1.7
Chapter 8: Decode Requests
General Options
Commands are transferred on USB using special control transfers called USB
Device Requests. The Analyzer can decode Device Requests as they are defined
in the USB specifications and various Device Class and Vendor specifications.
USB Request
Each USB Device Request is sent using a Control Transfer. Each Control Transfer
starts with a SETUP transaction.
To decode a USB Device Request, follow these steps, left-click once in the
SETUP field of the packet that starts the Request.
The Standard Request window appears .
Shown here is a GET_DESCRIPTOR Standard Request.