USB port change

Any technical questions about the Epiphany chip and Parallella HW Platform.

Moderator: aolofsson

USB port change

Postby aolofsson » Thu Mar 27, 2014 8:16 pm

We have decided to remove the U13 Micrel switch for production going forward to solve the potential burnout issues we were seeing with nonconforming powered hubs. With this change, we will also not have a hard limit of load 500mA on the USB port. This change has already been put into production.

ECO:
-remove U13
-put zero ohm resistor across pin 8,7 of the U13 footprint

We have tested the change on a number of boards and it looks good. With any change, there is some risk involved so we want to let you know about the change.

Schematic (old) for Reference:
http://www.parallella.org/docs/parallella_schematic.pdf

Andreas
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Re: USB port change

Postby Transcendental » Fri Mar 28, 2014 2:18 pm

aolofsson wrote:We have decided to remove the U13 Micrel switch for production going forward to solve the potential burnout issues we were seeing with nonconforming powered hubs. With this change, we will also not have a hard limit of load 500mA on the USB port. This change has already been put into production.
Andreas


Thank-you :)
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Re: USB port change

Postby Sean S » Mon May 19, 2014 5:39 pm

It seems that the USB on the Parallella is faulty. There are numerous posts in the forums of this problem. I would like to petition that Adapteva commit to providing a true understanding of the problem followed by a fix.

I have seen your ECO. This does not cure the problem. There is also a list of compatible USB devices. Using one of these does not guarantee that the problem is fixed. In addition, using a high power capable PSU does not fix the issue as well. And no, I have not used a powered hub.

The Parallella board is a great initiative but please realize that there is a BIG issue with USB. THIS NEEDS TO BE FIXED URGENTLY. I would like to know what Adapteva are doing in light of this problem and what the schedule is to fix it for once and for all.

PLEASE GIVE YOUR LOYAL CUSTOMERS A FIX FOR THIS ISSUE ADAPTEVA!
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Re: USB port change

Postby shodruk » Tue May 20, 2014 8:23 am

I want to note that my Parallella's USB has no issue now.
It works perfectly with this configuration. :D :D :D

http://elinux.org/Parallella_Speed_Up_Ubuntu
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