Y-cable and USB-OTG: mutually exclusive / the four connectivity solutions

Andy Green andy at openmoko.com
Thu May 1 11:21:11 CEST 2008

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Somebody in the thread at some point said:
| what i do not get out of all of this is:
| how do you want to detect usb enumeration when the user plugs it into
| the non-usb-otg port?

This is for the 500mA question?  Dunno yet, there can be pins on FTDI
that change state under this circumstance.  I have a scheme for
detecting charger insertion though and that is what is critical.

| and YES. when we have 2 identical sockets on it users WILL plug it into
| the wrong one.

Of course, but it will report itself as "Openmoko debug port" on the
host.  And simple cues like less accessible or recessed or Werner's red
rubber plug or USB symbol only on the OTG one can reduce it too.  So I
don't think this makes death, just something we have to manage.

| to have a only 'dumb power' and 'jtag' port would be somehow missing the
| point. especially when its behind a flap with screws.

That's what we try to clear up... we need to stop being stalled by
uncertainty and re-examination every week and make a decision how we
come at it.  Because people are trying to make schematics and first

If the point is to allow mains power / fast charge while we have OTG
peripherals connected, then this doesn't miss the point.  Maybe you can
elaborate about the point you have in mind and how to achieve hitting it.

- -Andy

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