Y-cable and USB-OTG: mutually exclusive

Werner Almesberger werner at openmoko.org
Tue Apr 29 15:16:56 CEST 2008

Andy Green wrote:
> Well I didn't hear the answer to this 100mA default issue yet.  Maybe we
> can find a pin that is active on the FTDI chip when it has a 500mA
> descriptor enabled.

If we include an EEPROM, we can program it to request 500mA. I don't
know what the default is.

> | It doesn't have to. All we need is some ADC that can probe what's going
> | on there.
> Probe what exactly?

Charger presence, i.e., the ID pin. I don't think there's a safe way to
also test whether D+/D- are shorted. (I.e., if the MPU or whatever does
this test is connected to D+/D-, it could block access to the FT2232,
and thus de facto brick the system.)

- Werner

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