Fast charging and the resistor trick
andy at openmoko.com
Fri Mar 6 10:27:34 CET 2009
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Somebody in the thread at some point said:
| I have a microcontroller based USB device and want to connect it to the
| Freerunner (in host mode). Now I need some clarifications on the resistor
| The two 15k Ohm resistors are indispensable to comply with USB-spec?
Yes, for reliable detection of the device presence.
| What will happen if I connect the device (with the resistors) to the
| of my computer? (The external power supply is turned of)
It should be fine.
| How do I have to design the USB endpoints on the device, so the
| does charge with 1A? Or do I need the 47k Ohm resistor if the FR is in
Only the 47K resistor is looked for to see if a charger is around.
| it is written that "Future kernels should switch to hostmode +
| when seeing this 47k resistor." Is this already implemented?
| Furthermore, it is mentioned that the resistors can be used to avoid
| of the Freerunner. I hope, I still can suspend if I want?
No idea what the author of that page is on about there, none of this
will impact either USB suspend or device suspend.
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