Thanks, Juha.  How would I have known that?  I would say that is a problem.



Eric Crossley

From: Juha Kuikka [via Gumstix] [mailto:[hidden email]]
Sent: Wednesday, December 19, 2012 1:07 PM
To: Crossley, J. Eric
Subject: Re: Embedded USB hub


On Wed, Dec 19, 2012 at 9:34 AM, Eric Crossley <[hidden email]> wrote:



Thanks for the information.  My intention was to operate at full-speed since our demands for data rates are low and it avoids issues associated with higher speed signals, but it may be that I interpreted the USB specs of downstream devices incorrectly (I haven’t engineered USB circuits before).  They are supposedly full-speed compatible but I will check further.


You do not specify which USB port of the gumstix you are using. The EHCI (USBH_*) port only supports High Speed USB 2.0 so it will not work with full/low speed hub or devices directly. If you need to use full/low speed devices they should be connected to a high-speed hub.


The OTG port (USBOTH_*) supports all speeds.


 - Juha

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