USB host

Harald Welte laforge at openmoko.org
Sun Aug 19 06:20:36 CEST 2007


Guys, hardware questions go to neo1973-hardware, not to community !!

On Mon, Aug 13, 2007 at 04:35:38PM +0200, Lars Hallberg wrote:
> Giles Jones skrev:
>> Marcin Domanski <groups at kabturek.info> wrote :
>>> Yep it shouldn't be a problem - let's take an usb hub with external
>>> power supply - connect it to neo and then connect the device to the
>>> hub. I dont know how's the support for it but its an idea :)
>> Here's how you solve the power issue:
>> http://www.radioshack.com/sm-cyberpower-4-port-battery-powered-hub--pi-2259675.html
>> A rechargable battery powered USB hub.
>
> I'm still not clear over this...
>
>  1) Will it be possible to charge the neo over the usb connection while the 
> neo is in host mode. 

for Neo1973 GTA01: definitely yes.  For GTA02 we will most likely supply
power to the USB in host mode, so that doesn't work, at least not
without complicated hacks ;)

> Will that raise special demand on the hub?

yes, or a special cable.

> A flexible powered hub (Wall, external battery pack, car-power(12V)... ) 
> that have any 'extra' function that the neo needs/benefits from would be 
> the perfect companion... almost a obligatory companion to the neo... But... 
> exactly what does it take to make such a beast?
>

We did think about this for some time, and actually I've designed the
architecture of such a device fairly far.   The idea was to even further
integrate that with the debug board, i.e. debug board plus
battery-powered hub in one device :)

But now that GTA01 is not really running at any reasonable quanatity,
and GTA02 will be able to supply 5V in host mode, it was abandoned.
We'd rather get GTA02 finished, then spend time on accessories that only
make sense for GTA01.

-- 
- Harald Welte <laforge at openmoko.org>          	        http://openmoko.org/
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