USB Host Mode Adapter
Rob Williams
rob at jumpnetworks.net
Thu Jul 3 17:59:13 CEST 2008
Hi All,
I'm not an OpenMoko guy by any stretch, but definitely a big supporter
of open source markets and neat devices like the FreeRunner. Anyways,
not sure exactly how things work on the OpenMoko hardware, but over on
the Nokia Internet Tablet (the N800) we had a similiar problem in that
the hardware supported USB OTG hostmode, but that since the tablets had
a MiniB and the OTG standard says that's a big no-no we had to come up
with our own solution. I did some reading on the power injection that
was required for the Neo, but it sounds like this has been solved on the
FreeRunner in the same way the Nokia's do it; have the equipment provide
a limited amount of power over the USB bus when placed into host mode.
On the Nokias you can engage host mode by having the ID pin of the
mini-B shorted to ground as per the USB OTG specs; I'm not sure if this
is true for the FreeRunner hardware, but if it is you may be very
interested in the solution we came up with:
http://www.electronicproductonline.com/catalog/product_info.php?products_id=1781
Right now I still build and test each of these by hand, but I'm getting
manufacturing lined up soon as it's become an extremely popular item
(I've sold over 500 so far). Anyways, if anyone reads this and is
interested or thinks it might work for the OpenMoko offerings let me know!
Thanks!
--
Rob Williams
Open Source Enthusiast
Electronic Product Online Ltd
www.electronicproductonline.com
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