Re: [Gumstix-users] Capabilities of USB OTG port

[Steve M. <mo...@sm...>]

On Jul 20, 2011, at 11:02 AM, Curtis Olson wrote:

> On Tue, Jul 19, 2011 at 1:38 PM, William Pretty Security Inc <bil...@xp...> wrote:
> I haven’t been to the wiki in a while so I’m not sure if it is still there.
> 
> However the standard way of connecting devices to the OTG port is by connecting
> 
> a hub to the port using a mini-A to mini-B cable. Available from Digikey or Gumstix.
> 
> I can get you the digikey catalog number.
> 
>  
> 
> Basically most devices like keyboards and mice are USB-1 devices. The OTG port is USB-2 only.
> 
> So you need the hub as a translator. There used to be a bunch of information on the wiki
> 
> about this, but it may have been removed. If you are still stuck, I can recommend some USB
> 
> hubs for you …
> 
> 
> Hi Bill, thanks for the quick reply.  I did a google search for "site:wiki.gumstix.org usb" and didn't turn up a lot of information, at least not on the first two pages of results.  The USB link on the main wiki page links to a howto for running a TCP/IP stack on top of the USB-OTG port -- I guess I'll file that away for future interest I could see that being a handy option down the road.  Maybe this is just one of those basic questions that once you figure it out the lay of the land, you understand what's going on so there's no need to document. :-)
> 

I looked into this  while back as well.  The issue is that the chip uses a different backend interface when running in OHCI mode.  That interface is evidently not in the kernel driver, so it doesn't work.  I imagine it could be made to work, but who would want to do that! :)



> The "usb hub" wiki page links to a non-existent dynexproducts.com url ...
> 
> Does the usb hub need to provide it's own 5v power source?  I plugged in a usb hub I have here into my tobi board, but the little red led on my hub never comes on so I'm guessing the overo doesn't provide power to the USB OTG port?
> 
> Thanks,
> 
> Curt.
> -- 
> Curtis Olson:
> http://www.atiak.com - http://aem.umn.edu/~uav/
> http://www.flightgear.org - http://gallinazo.flightgear.org
> 
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