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USB Advisor User Manual Chapter 6: Reading a Trace
LeCroy Corporation
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6.22 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 > Show PTP Transaction .
OR
• Select Setup > Display Options to display the Display Options window,
check PTP Transaction , and then click OK.
6.23 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 PTP Transactions that involve a single Asynchronous Event sent
through the interrupt pipe.
The PTP Object Transfer trace viewing level is the middle PTP level.
To view PTP object transfers, switch to the PTP Object Transfer trace viewing level:
• Click on the toolbar.
OR
• Select View > Show PTP Object .
OR
• Select Setup > Display Options to display the Display Options window,
check PTP Object , and then click OK.