I am using the Beagle USB 480 Protocol Analyzer for USB 2.0 captures. I’m trying to get information and measure timing of every IN-NAK at a specific point on an existing capture file. Using the Data Center Software, I can only get the timing of the first IN-NAK. How do I get the timing of the17th IN-NAK, which is highlighted in the screen shot below?

Figure 1: Collapsed IN-NAKs

Also, I need to view the 15 PING-NAKs that occur. How can I get that information?

Figure 2: Collapsed PING-NAK Events

Thanks for your questions! When using the Beagle USB 480 Protocol Analyzer with the Data Center Software there are several views available for analyzing the data, and in particular to look at individual packets and their associated details.

• First, before starting a capture in Data Center, go to Analyzer > Capture Settings > USB.

Figure 3: USB Capture Mode Settings

• Second, make sure the Sequential and Data-less Sequences checkboxes are selected as shown below.

Figure 4: Sequential and Data-less Sequences

Here is some information about three of the available Capture 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.

For viewing the individual IN-NAKs, we recommend using the Packet View. To select this view, use the Capture View Menu in the Transaction Window Controls section of the Data Center Software application. For additional information, please refer to section 6.7 of the Data Center Software User Manual.

To answer your second question about viewing the 15 PING-NAKs that occur, with the Sequential and Data-less Sequences checkboxes selected, you will see the individual PING-NAKs as well. For additional information, please refer to section 6.2.2 of the Data Center Software User Manual.

Additional resources that you may find helpful include the following:

• • Beagle Protocol Analyzer User Manual

  • Data Center Software User Manual

  • USB Specifications

  • About the USB Protocol, Common USB Bus Errors, and How to Troubleshoot Them

We hope this answers your questions. If you have other questions about our protocol analyzers or other Total Phase products, feel free to email us at sales@totalphase.com, or if you already own one of our devices and have a technical question, please submit a request for technical support.