Q: How does USB hubs work? Re: Multiple USB Devices

Harald Welte laforge at openmoko.org
Sun Feb 4 15:36:29 CET 2007

On Sat, Feb 03, 2007 at 09:15:54AM -0700, Joe Pfeiffer wrote:
> Harald Welte writes:
> >> 
> >> My understanding is that it will be USB On-The-Go, 
> >
> >No.  OTG is a complex specification, and it comprises way more than just
> >a AB socket, but also electrical and software components which we cannot
> >provide using the S3C2410.
> Thanks for the correction.  This is interesting....  do I understand
> you to mean that the NEO can behave as either a host or as a device
> depending on how it's plugged in, without support OTG?

Yes.  OTG is one specific, quite complicated (on multiple layers)
approach to automatically do the right thing, if you have compliant

We're basically able to electrically switch the usb socket from host to
device and vice-versa,

1) manually (by software)
2) automatically in OTG-similar way based on 5th pin of mini-B jack.

but we cannot do all the higher layers (such as negotiating with another
device who will be host and who will be device, etc.)

- Harald Welte <laforge at openmoko.org>          	        http://openmoko.org/
Software for the world's first truly open Free Software mobile phone

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