Thread: Jolla hardware compatibility
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joerg_rw is offline joerg_rw
2013-12-28 , 12:13
Posts: 2,222 | Thanked: 12,651 times | Joined on Mar 2010 @ SOL 3
#26
Originally Posted by qwazix View Post
The N9 also refuses to charge via apple charger, which probably isn't a dumb charger. It complains about not enough power.
Apple charger has a resistor voltage divider on both D+ and D-, fed from 5V VBus, so you have signalling analog voltage levels on D+ and D- telling iPhone how much the charger can do.
you have to supply with voltage dividers the Data pins D- and D+ with specific voltages, and of course the +5V Vcc and ground. The specific voltages is 2,6V on D- and 2,1V on D+.
This doesn't work for N9, as elaborated above, since N9 only checks for the simpler more robust D-/- shortcircuit to detect fastchargers that are supposed to deliver at least 1200mA or somesuch. Otherwise N9 will assume USB host and try to enumerate and negotiate max VBus current it may draw. Neither of both works with Apple charger.

recommended read: http://learn.adafruit.com/minty-boost/icharging

/j
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Last edited by joerg_rw; 2013-12-28 at 12:42.
 

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