vertical space (was Re: 3D Scanning)

Carlos Camargo cicamargoba at gmail.com
Wed Jul 14 17:58:05 EDT 2010


Hi


> > Mandatoty signals: GND, VCC,
> > usb (2) SD(7) Audio(6) keyboard (16)
>
> Even if the whole power/charging circuit lives in the bottom shell,
> don't you also need some control signals, plus +VBUS for ADIN0 ?
>

You're right we need to include these signals.


>
> USB also needs USBDET, plus, when adding USB host, another pair of
> D+/D-. By the way, how would USB host be supplied with power ? How
> have you done it in SAKC ?
>

The Ya CPU 4760 have OTG USB, we need to make some test on 4760 reference
board first, in AVT2 board, one BEN variant, we use a DC/DC converter for
USB host power supply. SAKC use 4725, this chip has usb device only


> Perhaps the keyboard's voracity could be contained a little by
> adding some multiplexer or even an MCU dedicated to just keyboard
> handling.
>

I like the idea of using a little MCU so, the people can create different
interfaces, push buttons, capacitive, etc, so we must provide 3 or 4 lines
for ISP.


> The current on VCC and GND may also be too large for that FPC,
> requiring either multiple traces, or an additional FPC/cable.
>

Agree


>
> That's already quite a lot of stuff and it doesn't even include
> the signals we'd want to run to the new peripherals we'd want to
> be able to add :-(
>

We can use two tapes, one for basic operation and another one for hardware
hackers, but it depends of how easy is change the current case.


> If Wolfgang can get the new CPU in an MCP with stacked RAM and
> (evil) NAND, the routing should also get a bit easier.
>
> yes, data, address and control buses are difficult to route if you have two
or three memories.


> Being able to modify the keyboard would be very interesting
> indeed. Even better if you get to play with the whole board
> underneath too. Metal domes of the right kind seem to be
> available to the public, e.g.,
> http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=SW1018-ND


Great!!! in this case we can replace the entire layout for custom
applications.



> One problem would be that the MicroSD holder probably still has
> to go under the keyboard. (Unless you move it into the LCM shell
> as well.)
>

As I said, It depends, if we can make little changes on case I prefer have
the microSD holder into LCM shell



Carlos




>
> - Werner
>
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-- 
Carlos Iván Camargo Bareño
Profesor Asistente
Departamento de Ingeniería Eléctrica y Electrónica
Universidad Nacional de Colombia
cicamargoba at unal.edu.co
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