Clarification Needed

Posted: 7 months ago Quote
Hi,

It took a bit to understand that the 1480A needs to see the DUT plug-in sequence so that it can understand the jump to HS. You might add some UI that detects if activity is already being successfully tracked, and if not, tell the user to press "start" AND THEN connect the device. But sometimes I think the 1480A needs to ALWAYS see the plug-in sequence, is that true?

I don't understand the Filter settings. If I go in an change the filter settings, then the current acquisition seems to go away. This suggests the Filter settings will clear the current log AND apply to the next acquisition. is that true? I ask because sometimes if the current capture is short, then the settings seem to be applied.

In the full log, I can see activity on endpoint 2. If I set the filter to hide traffic on endpoint "0-1", I never see the log get restored with just EP 0 and EP 1 gone. How can I see traffic just on EP2 if I have already captured the data? Also, is the Device ID required, or can I just specify endpoints? Because the data seems to always go away, it's not clear.

Next, I think you need a message that data is being processed. There are times when the software seems show nothing is happening, but then 30 or 60 seconds later I see the COUNT field in the Node Finder flicker to life suggesting there's an enormous amount of data that must be parsed...

Sometimes the LINK ACTIVITY light is off, but I can control my USB device from my app. Why is no activity being reported when obviously there is activity?

Sometimes when I 1) unplug my device, 2) press start, 3) plug in my device, I never see link activity. This is in spite of Windows playing the 'connect' sound and my app being able to control the device. In the log, I see the Device Chirp times out. Is that why?

Thanks very much!
Posted: 7 months ago Quote
Hi Matt

"It took a bit to understand that the 1480A needs to see the DUT plug-in sequence so that it can understand the jump to HS. You might add some UI that detects if activity is already being successfully tracked, and if not, tell the user to press "start" AND THEN connect the device. But sometimes I think the 1480A needs to ALWAYS see the plug-in sequence, is that true?"

Yes, the capture needs to be started before the host and DUT is connected. This is such that the 1480A will know which speed to configure its PHY in. This is discussed in the below support forum post:

http://internationaltestinstruments.com/boards/t/113/the-1480a-capture-must-be-started-before-the-device-under-test-is-connected.aspx

"I don't understand the Filter settings. If I go in an change the filter settings, then the current acquisition seems to go away. This suggests the Filter settings will clear the current log AND apply to the next acquisition. is that true? I ask because sometimes if the current capture is short, then the settings seem to be applied."

The filters will be applied to the current capture session, even if the trace has not been fully parsed out. This is how it works:

In order to correctly parse out the trace data with the correct nesting of all data nodes, the 1480A software parses the .usb file, from the beginning to end, and creates various data files that then are loaded and displayed by the various panes in the GUI. If the filter settings are changed, the 1480A re-starts the parsing from the beginning but throws away the filtered out nodes from  the resulting data files that the GUI loads. This is essentially how the filtering works. There is some more information on the various data files being generated here:

http://internationaltestinstruments.com/boards/t/16/usb-file-format.aspx

http://internationaltestinstruments.com/boards/t/48/how-to-export-binary-packet-data.aspx

"In the full log, I can see activity on endpoint 2. If I set the filter to hide traffic on endpoint "0-1", I never see the log get restored with just EP 0 and EP 1 gone. How can I see traffic just on EP2 if I have already captured the data? Also, is the Device ID required, or can I just specify endpoints? Because the data seems to always go away, it's not clear."

It should be sufficient to just enter the endpoint number. Perhaps there is something in your particular trace that causes to trouble for the software. If you zip up and email the .usb file to support at international test instruments dot com then I can take a look.

"Next, I think you need a message that data is being processed. There are times when the software seems show nothing is happening, but then 30 or 60 seconds later I see the COUNT field in the Node Finder flicker to life suggesting there's an enormous amount of data that must be parsed..."

If the software is not updating the GUI every second it means that you have some very deep nesting or some other unusual content in the trace hierarchy. The .usb file parser will write the resulting data files to disk every second if a new top-level node is available. If, for instance, there is a top level node that has thousands of sub-nodes underneath, then the GUI has nothing new to display until the node parsing is completed. Please zip and email to me and I'll take a look.

"Sometimes the LINK ACTIVITY light is off, but I can control my USB device from my app. Why is no activity being reported when obviously there is activity?"

The link activity LED flashes every 250ms if any data packet has been detected on the link under test in the last 250 ms. If there is continuous traffic you should see a 4 Hz LED activity. But, make sure you start the capture before connecting the DUT.

"Sometimes when I 1) unplug my device, 2) press start, 3) plug in my device, I never see link activity. This is in spite of Windows playing the 'connect' sound and my app being able to control the device. In the log, I see the Device Chirp times out. Is that why?"

Could you please zip and email this .usb file so I can take a look.

Thanks
Steve.
Posted: 7 months ago Quote
Hi Steve, thanks for the clarification. it's very helpful

There must be something going on that is taking so long for the file to parse. But I suspect it's something I'm doing wrong which is why I bought the analyzer in the first place.

I see your tutorial web page, but I still don't understand what "discovered devices" are showing. Your samples have a single or two discovered devices, but when I collect anything (from an JTAG probe to a USB drive) I have lots and lots of discovered devices, and transactions to most all of them fail and there are roughly 50% of the lines in the log are incompletes.

What would cause me to have so many discovered devices? I only see a form for contact. Do you have an email I can send the trace?

Thanks very much!
Posted: 7 months ago Quote
Hi Matt. Please zip up the .usb file and email us at support @ international test instruments . com (remove spaces) and I'll take a look.

Thanks,
/Steve