Hi,

My device seems to be having trouble completing HS negotiation when being analyzed, not so when connected directly to the host PC.

If, however, the analyzer is plugged to the host when the device has already been plugged to the analyzer, HS negotiation seems to complete - however, I see no packets when capturing...

Please advise.

Thanks in advance,
dd.

This is most likely a cabling problem. Please try to use as short cables as possible between your device under test <=> the 1480A unit <=> your host PC. Also make sure you are using good-quality, certified cables for the device under test. We are currently sending two different cables with the 1480A unit; a white one that only should be used between the 1480A and the analysis PC and a gray one that should be used for the link under test. Originally, we found an issue with the white cable when used on the link under test for high-current devices like external USB hardddrives. This is why we have two different cables. Make sure you have not mixed up these cables.

Hi,

I also faced the same problem. But I connected the cables as per what you mentioned. My problem is, my host is properly worked when the standard pendrive (high speed usb device) is directly connected to its port (device is settled in HS mode and done control transfer). But through 1480A unit, I found device is settled in FS mode, and it is continuously restared.

Please advice me.

Regards,
senthil.

senthil wrote:

My problem is, my host is properly worked when the standard pendrive (high speed usb device) is directly connected to its port (device is settled in HS mode and done control transfer). But through 1480A unit, I found device is settled in FS mode, and it is continuously restared.


Please send the resulting .usb file to support @ international Test instruments . com and we'll take a look at the trace. This seems to indicate that there is a cabling problem. If bad cables are used you may very well end up with a case where direct-connection between your host and device works but the HS communication fails when the 1480A unit is plugged in between. Also make sure that you are using short cables (say 1m / 3ft) on the link under test. This could also be caused by a host controller that is badly designed.

In short, any impedance mismatches on the link under test will cause reflections and bad behavior in high-speed mode. Bad cables etc could be the cause.

Also make sure that you are using short cables (say 1m / 3ft) on the link under test.
>> yes. I am using the same cable what you shipped with 1408A unit.

Attachments:
hs_problem.usb

Could you tell me exactly what pendrive you are using? We could then pick up the same and see if we can reproduce the issue.

The trace you posted shows that your host PC doesn't send any Start of Frame packets after having entered HS mode. The chirp sequence tells us that the host correctly sees the device chirp and responds correctly with host chirp. After that the link is suspended in J-state for more than 3ms which causes the HS Idle tree node to be displayed.

As far as I can tell everything looks okay except for the fact that the host simply doesn't drive SOFs or any other traffic on the link under test. We have found that some low-quality host controller cards are sensitive to impedance changes on the link under test such that when a cable is used HS fails. Could you try to use a USB extension cable (passive cable) between the host pc and your pen drive to make sure that this works? Also, try to use another host PC on the link under test as well as another device than your flash key.

We have sold lots of these units and normally connection issues are due to bad cables or bad host controller cards.