Teledyne LeCroy USB Protocol Suite User Manual (Voyager_Advisor T3_Mercury) - Manual (Page 139)

USB Protocol Suite User Manual 139
Decoding Protocol‐Specific Fields in Transactions and Transfers Teledyne LeCroy Corporation
It is not necessary to use the Expand/Collapse Transfers menu to shift between expanded
and collapsed views of a transfers. You can double‐click the Transfer number field to
toggle back and forth between collapsed and expanded views.
5.31 Decoding Protocol-Specific Fields in Transactions and Transfers
When transfers or transactions are displayed, the fields in setup transactions and in
control, interrupt, and Bulk transfers do not get decoded (by default) and are shown in
hexadecimal values. The exceptions are setup transactions and control transfers for
standard USB device requests, which are always decoded.
To show specific decoding for class‐ and vendor‐specific device requests and endpoints,
you have to use the decoding association mechanism that is described in Chapter 9 on
decoding. When you have performed the association, you see the protocol‐specific fields
of transfers and transactions decoded in the trace view.
5.32 Switch to PTP Transactions
The Analyzer supports the Picture Transfer Protocol (PTP) and also supports the
Media Transfer Protocol (MTP), which is an extension of PTP. The Analyzer can track PTP
transactions, object transfers, and sessions.
A transaction is a standard sequence of phases for invoking an action. In PTP, an Initiator‐
initiated action provides input parameters, responses with parameters, and binary data
exchange, and is a single PTP Transaction. Also, a single Asynchronous Event sent through
the interrupt pipe is a single PTP Transaction.
The PTP Transaction trace viewing level is the lowest PTP level.
To view PTP transactions, switch to the PTP Transaction trace viewing level:
 Click on the toolbar.
OR
 Select View > PTP Group > PTP Transaction Level.
OR
 Select Setup > Display Options to display the Display Options window, check PTP
Transaction, and then click OK.
5.33 Switch to PTP Object Transfers
A logical object on a device has a unique 32‐bit identifier (object handle). The
object handle is also unique for the session (defined below). An object transfer contains
all the transactions for an object handle. In PTP, all of an object handle’s PTP Transactions
are a single PTP Object Transfer.
A PTP Object Transfer can include both PTP Transactions that involve an Initiator‐initiated
action (for example, GetObject, DeleteObject, and GetObjectInfo transactions) and