Problem with battery charging

[Nils Faerber]

Ah, yes, that explains it.

Thanks!

I guess there is no way to distinguish between the charger and a real
USB host? Probably not, else you would have implemented it I am sure...

Cheers
  nils


Harald Welte schrieb:
> On Wed, Mar 21, 2007 at 02:08:04PM +0100, Nils Faerber wrote:
>> Hi!
>> I just recognised a little issue with battery charging...
>>
>> Yesterday I put the NEO on the charger and let it boot. It booted up
>> fine and started charging the battery.
> 
> please don't use the battery charger, as it will only charge with 100mA,
> which will take at least 12 hours to fill the battery, if the device is
> switched off.  
> 
> if you keep the device running, it will consume more than 100mA, and
> thus actually run empty - just a bit slower than it would without the
> charger.
> 
> With devices up to GTA01Bv3 and the current charger we basically have no
> way of using a non-usb-host for charging without violating the USB spec.
> 
> So now we have the choice between USB incompliant 500mA charging (which
> might in some really bad cases cause damage to the 'usb host' it is
> attached to.
> 
> Thus, we'd rather done it the safe way:  Only use 500mA after the USB
> host has granted us permission to do so.
> 
> I know that it's almost industry practise to violate this part of the
> spec.  However, OpenMoko wants to set a good example and adhere to
> standards :)
> 
> GTA01Bv4 and the new charger hardware contain circuit changes to address
> this problem in a usb spec compliant way.
> 
> you can manually override the charging mode via sysfs or in u-boot, if
> you really want to use the charger for 500mA charging. see the kernel
> and u-boot pages in the wiki.
> 
> cheers,

Viele Grüße
  nils faerber

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