maemo.org - Talk

maemo.org - Talk (https://talk.maemo.org/index.php)
-   General (https://talk.maemo.org/forumdisplay.php?f=7)
-   -   N810 and USB OTG Cable - my homemade solution. (https://talk.maemo.org/showthread.php?t=20288)

Benson 2008-05-23 14:40

Re: N810 and USB OTG Cable - my homemade solution.
 
Quote:

Originally Posted by yabbas (Post 184753)
Let us know what outcome you get Benson :) I'd be interested to know if the pads are USB related!

Well, no more from Texrat, so I guess he expired.

Those pads (on an N800) are USB...
Code:

  A

  B
C
  D

A & B are data (sorry, not sure which was +)
C is ground
D is +5V

Of course, as you can see from the picture I linked, they're laid out differently on the N810:
Code:

      A

      B
D  C

(But the identification of signals<->pads, or even that this is the same connector, is pure speculation...) I'm betting that's USB, too.

Could Nokia have been designing ahead for peripheral back-plates here? I think not; else there'd be an OTG sense pad, too. I think they just have a fixture you can drop a bare N800 in and provide power and a USB connection for flashing.

Any use of this will probably require software switching or hardware hackery (adding a switch to toggle OTG, and also disconnect the data lines, would permit connection to a PC through the mini B port).

yabbas 2008-05-23 15:24

Re: N810 and USB OTG Cable - my homemade solution.
 
So next questions:
...are these pads the same as the connector on the side, or have we got access to a second USB connector now?
...is the +5V restricted to 100mAh like the OTG socket?
...and can we create our own peripheral back plates with spring probes to USB-A?


I don't think software switching would be a problem for users. But having to swap backplates all the time (if you wanted to plug it into a PC) would be irritating.




Peripheral back-plates, here we come! :D

Benson 2008-05-23 15:44

Re: N810 and USB OTG Cable - my homemade solution.
 
They're the same port; if they weren't, there'd have been no data on the pads for me to watch...

I presume the same current limitation applies; it can be disabled with a kernel tweak, provided the backpack also has a battery and power-injector; or just use a powered hub, get more ports and no kernel tweak needed.

Yes, we can make peripheral battery-packs with a power injector or powered hub, a fat-max battery, wired ethernet adapter, USB-RS232, and even SIS-based USB-VGA.

(Or, you could leave some of that out, but I would include everything except maybe the USB-VGA. With switches to disconnect everything, there's no power drain unless you use it...)

jolouis 2008-05-23 19:53

Re: N810 and USB OTG Cable - my homemade solution.
 
Well there you go, long time suspicion finally confirmed! Thanks Benson!
I had imagined that the pads were just second points for the original USB connector, as Benson mentioned, since it really doesn't make sense based on the location and device to be brought out otherwise.
Of course how practical all this turns out to be is another question, but with the ingenuity that's kicking around these forums I'm sure there will be some interesting (if only one off and impossible to reproduce) results...

ldrn 2008-05-23 22:50

Re: N810 and USB OTG Cable - my homemade solution.
 
Wow, that's awesome! Thanks Benson.

Quote:

Originally Posted by Benson (Post 185111)
I think they just have a fixture you can drop a bare N800 in and provide power and a USB connection for flashing.

So in that earlier thread, Texrat was telling the truth in the most misleading way possible? :eek:

Benson 2008-05-23 23:05

Re: N810 and USB OTG Cable - my homemade solution.
 
Would he ever do that?

(I think he was actually being completely honest, and correct, but didn't know the whole story...)


All times are GMT. The time now is 20:06.

vBulletin® Version 3.8.8