USB host successes

Al Johnson openmoko at mazikeen.demon.co.uk
Wed Sep 10 00:46:46 CEST 2008


On Tuesday 09 September 2008, Joel Newkirk wrote:
> On Tue, 09 Sep 2008 12:35:44 -0700, Michael Shiloh <michael at openmoko.org>
>
> wrote:
> > I've tried to answer many of these questions here:
> > http://wiki.openmoko.org/wiki/USB_host
> >
> > If you feel this information is unclear, lacking, or wrong, please
> > correct or please let me know.
> >
> > In particular, I'd love people to add any specific setups they have that
> > are working.
> >
> > Michael
>
> Thank you - exactly the information needed.  The 47kohm resistor (between
> ID and GND) is needed to signal 1000mA charging permitted (that's what I
> was thinking of when I wrote about the 15k pair in my previous post), per
> both http://wiki.openmoko.org/wiki/USB_host and
> http://wiki.openmoko.org/wiki/Specialized_USB_cables, but unless I'm
> misreading they seem to contradict one another regarding the 15k pulldowns
> on D+ and D-.  What is the correct info regarding those?

Looks entirely consistent to me. With power management host mode disabled the 
FR can accept charge, but the 15k pulldowns in the FR that would normally be 
connected to D+ and D- in host mode are also disconnected. For host mode to 
operate correctly we have to add these to the Y-cable.




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