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Support Question of the Week: Viewing Timestamps for USB 2.0 Transactions

Q: I'm using a Beagle USB 480 Protocol Analyzer to monitor some USB data from a mouse. When I plug in the device and run a capture, the timestamps don't always show up in chronological order. Is there a function I can use in Data Center Software so that I can view the transactions in chronological order?

A: Thanks for your question! When using the Beagle USB 480 Protocol Analyzer with the Data Center Software as a high-speed USB sniffer, there are several capture views you can use to view your data. Here's some more information on the three different types of views:

  • Packet View : In this view, protocol-level decoding is performed and the transactions are displayed chronologically. Collapsed groups of data, such as SOFs and IN-NAKs are broken up as necessary to ensure that records are in the timestamp order. Please note that only captures run in Sequential mode can be viewed in Packet View. To make sure a capture is run in Sequential mode, go to the USB Capture Settings window and select Sequential as your capture mode.
  • Transaction View : For this view, protocol-level decoding is performed and collapsed groups of data are not broken up for time-order preservation. With no time-order restriction, the captures generally appear more compact in this view than Packet View.
  • Class View : Class-level parsing is performed on the USB data transactions and the capture usually appears high-level and compact with this view. Records may not appear in chronological order.

It sounds like you may be viewing your capture in either Transaction View or Class View. If you want to capture and view your data in chronological order, be sure to go to USB capture settings, set your capture mode to Sequential, and view your transactions in Packet View.

Make sure to select Sequential mode in your capture settings if you want to view data in chronological order under Packet View.

After you run your capture in Sequential mode, apply the Packet View by selecting the drop-down menu in the Transaction window, as highlighted in the picture below:

The arrow points to where you can change the capture view to Transaction, Class, or Packet view.

One important thing to note is that Packet View is available for Data Center captures using the Beagle USB 480 analyzer and the Beagle USB 5000 v2 SuperSpeed Protocol Analyzer (our USB 3.0 bus monitor). For Beagle USB 12 Protocol Analyzer users, only the Transaction and Class views are available for Data Center software captures.

We hope this answers your question! If you have any other questions about our Beagle USB protocol analyzers, Data Center Software, or Total Phase products, feel free to email us at sales@totalphase.com or support@totalphase.com.