Y-cable and USB-OTG: mutually exclusive

Joerg Reisenweber joerg at openmoko.org
Tue Apr 29 12:14:32 CEST 2008

Werner Almesberger schrieb:
> Joerg Reisenweber wrote:
>> And we lose our USB-OTG cert,
> The question is also whether we care about such a certification, or if
> we're happy with complying with the relevant parts of the standard and
> don't put any fancy labels on the box.

When I asked this question, either Raster or Harald tld me, we're even
going to pay quite some money for it.

>> it surely will hit us
>> with two (identical!!!) external USBcon.
> Well, now here's a challenge for our ID team ;-) "Make it mechanically
> the same, yet distinct enough that people won't confuse it."
> One idea I had was to just put a bright red rubber plug into debug-USB
> socket, and mention it somewhere on the in-the-box documentation (e.g.,
> picture, "This port is for power and debugging.", and a URL on the
> welcome carda). That will make people notice that there _is_ a
> difference, and they'll probably remember this even after they've lost
> that little red plug.

That's fine for me, probably ot for USB-cert.

> By the way, do we still need that Y-connector if we feed power into
> the debug-USB socket ?

Nope! :-)

> By the way 2: drawing power from debug-USB also needs charger detection
> and a current limiter for 100mA vs. real power.

Right. Never will happen, FTDI chip can't do this I think. :-((((
So we're back again to my lovely little coax ;-) Much smaller than 2nd
micro-USB, much simpler, many many compliant chargers out there.


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