On Wed, Dec 19, 2012 at 9:34 AM, Eric Crossley <eric.crossley@jhuapl.edu> 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 havenít 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