[maemo-users] N900: Force charging on USB?

From: Nils Faerber nils.faerber at kernelconcepts.de
Date: Wed Apr 14 19:13:25 EEST 2010
Nils Faerber schrieb:
> Joerg Reisenweber schrieb:
>>> So assuming I know what I am doing is there a way to enforce the N900 to
>>> start charging even if there is no host connected? This must work
>>> somehow since the power adapter presumably does not contain a USB host ;)
>> Exactly. The charger shorts D+ and D- data lines of USB port.
>> This should enable fast charging
> Ah!
> I will try that - press thumbs that it works ;)

And it does!

And actually Simon Budig found out that this is spec compliant:

"The Dedicated Charging Port shorts the D+ and D- pins with a resistance
of at most 200Ω. The short disables data transfer, but allows devices to
detect the Dedicated Charging Port and allows very simple, high current
chargers to be manufactured."

I guess it is just a matter of time that newer "USB chargers" implement


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