How to tell if a powered USB hub is certified

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How to tell if a powered USB hub is certified

Postby Gravis » Tue May 13, 2014 9:53 pm

In my search to find a certified USB hub (so that I don't blow up my Parallella), I found there this is actually a list of all the certified USB hubs that is maintained by the people that do the certifying.

I found the F5U404-BLK to be particularly nice and quite inexpensive. you can get it on amazon here: http://www.amazon.com/gp/product/B000SAB34O
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Re: How to tell if a powered USB hub is certified

Postby Reiner » Thu May 29, 2014 12:12 pm

I just bought a brand new powered usb hub. The dealer said that it would definitly be suitable and fully compliant with the usb standard. Other people are using it with their raspberry pi which is also very sensitive to non-conforming usb hubs. While using it I accidently ripped of the power plug from the parallella. I was really very much astonished when I realized that the green led was still on! I guess that there was some current from the usb hub going back to the parallella. I think that this is the same effect that Andreas Olofsson has described in this post:
viewtopic.php?f=10&t=841&p=5274&hilit=+usb+hub+fried#p5274

Luckily my board still works but i cannot say if it is damaged in some way. Even though I am not quiet sure if this hub is dangerous to the board i would say that you better not use it with the parallella. Correct me if I am wrong.

The hub I used was the 10-port usb-hub from logilink (UA0096):

http://www.logilink.eu/Products_LogiLin ... anguage=en
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Re: How to tell if a powered USB hub is certified

Postby aolofsson » Thu May 29, 2014 2:08 pm

We always recommend using conforming USB hubs, but in case you have one of the latest batch of Parallella boards, you may be ok...

Can you check whether the U13 device next to the USB port is populated. The critical failure mode we observed earlier was in the U13 device and we have now removed it in production. Long term, the board was not designed to draw 1+A through the host micro-USB connector so you really shouldn't power the Parallella that way, but it is unlikely to fail in seconds.

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Re: How to tell if a powered USB hub is certified

Postby Gravis » Mon Jun 09, 2014 11:40 am

Reiner wrote:I just bought a brand new powered usb hub. The dealer said that it would definitly be suitable and fully compliant with the usb standard.

never trust a salesman.
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