Michel, this is a perfect description of the current situation. You have to wear the t-shirt yourself! :-)
cherrs jOERG Am Fr 28. März 2008 schrieb Michael Shiloh: > Correct me if I'm wrong, but I think the big problem is that there is no > standard for reporting current capacity other than the USB protocol, > which is not supported by dumb chargers. > > What this means is that the various tricks that we and others play > (shorting unused data pins, adding resistors of specific values between > two pins, etc.) are all completely non-standard meaning there is no > agreement between manufacturers and most importantly NO PROM > iSE THAT FUTURE DEVICES OF THE SAME MODEL NUMBER WILL USE THE SAME > TECHNIQUE! > > In other words we could test a given Motorola charger today, find that > they have a resistor of value x between two pins, write the code to test > for this value and then bump up the current draw to the value that we > know the Motorola charger can provide. > > But then next month Motorola might change the value of this resistor. > They might send a firmware update over the air to all their phones to > make existing phones compatible with the new charger. > > We, of course, do not get this update, and suddenly the charger that we > had tested no longer works. > > For a good example of this problem see Lady Ada's discussion on her > Minty Boost. You will see a string of reports from people saying they > needed to modify the resistor value and/or location in order to get > Minty Boost to work with different models of iPods. And any solution is > always temporary, until Apple changes something and then the resistor > must change again. > > Thus the only way we can guarantee safe charging at higher than the USB > maximum of 500mA is with our own charger. > > I would love to see a technical report, a white paper, written on this > issue. Would anyone like to take on the challenge? Winner gets an > Openmoko t-shirt (http://wiki.openmoko.org/wiki/SWAG) > > Michael > > Kevin Dean wrote: > > O> > community@lists.openmoko.org > > http://lists.openmoko.org/mailman/listinfo/community > _______________________________________________ Openmoko community mailing list community@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/community