[linux-audio-dev] synthesis on gp2x .. (was Fwd: RE: [gpx-dev] hardware interfaces)

Jacob jacob01 at gmx.net
Wed Jan 18 20:06:38 UTC 2006


On Wed, Jan 18, 2006 at 01:16:55PM -0600, Richard Smith wrote:
> > > Sounds great, but I'm a little bit confused by other information I found
> > > on the web about USB host mode support:
> >
> > I'm confused too.  I've never heard of "USB host mode", what is it?
> 
> I believe he is refering to if the device can operate as a USB host
> bridge rather than just as a usb device.  OTG devices and some
> embedded chips can be both.

Yes, that is what I'm refering to. AFAIK I haven't any chance to access
an USB 'device' (device/slave/peripheral mode, eg MIDI/audio interfaces)
from another one that isn't capable to do/switch to 'host mode', be it a
host controller or an on-the-go (OTG) device.

Citing from http://en.wikipedia.org/wiki/USB

  A USB system has an asymmetric design, consisting of a host controller
  and multiple devices connected in a tree-like fashion using special
  hub devices, called USB hubs.

and

  An extension to USB called USB On-The-Go allows a single port to act
  as either a host or a device - chosen by which end of the cable plugs
  into the socket on the unit. Even after the cable is hooked up and the
  units are talking, the two units may "swap" ends under program
  control. This facility targets units such as PDAs where the USB link
  might connect to a PC's host port as a device in one instance, yet
  connect as a host itself to a keyboard and mouse device in another
  instance.

Jacob  



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