this phone, with WiFi

Visti Andresen talpa at
Tue Jul 17 21:25:49 CEST 2007

On Sun, 15 Jul 2007 17:56:19 -0400
Clay Williams <claytonw at> wrote:

> Quoting Christian Fischer <christian_tud_ist at>:
> > Doug Jones schrieb:
> >
> >> Assuming one has an appropriate cable, and assuming one can find some
> >> way to get power into the thing, it ought to be possible to make it work
> >> with the Neo.  (The Neo that is hopefully shipping next week, the one
> >> without built-in WiFi.)
> >
> > The USB-Bus Device is unpowered. It uses external Power for Battery
> > Charging.
> >
> > So try to make your own 5V supply.
> >
> >
> > Christian
> >
> If you do decide to go this route (building a 5V supply), you can power 
> it from
> the neo's 3.7V battery with an LM2621 chip from national semiconductor. It
> claims to have 87% efficiency converting 3.6V to 5V with a 500 mA load. Does
> anyone know what kind of current a USB WLAN card draws?

Less that 500mA as that is the maximum for an USB device :)

> The chip also has a "shut-down" mode in which it draws very little current.

Yes you would probably want to let the enable signal be controlled by a
GPIO pin 

> I may try this in the near future, since I am interested in using other USB
> devices.
> Another option is a battery powered USB hub, like this one:

The hub is probably quite useless as it is powered by 4 AA batteries (thats 4.8V)

> Anybody know if that'll work? I'm just starting on this project...
> -Clay

It PROBABLY would work, that is if:

You find the room for the hack 

Not a problem with two usb slaves on the same cable
(the neo it self need to be a slave for firmware upgrades and such)
you can definitely have two usb devices on the same bus
(my usb web cam is both an video device and an audio device)
but I'm not sure if it is okay with two USB PHY transceivers on the same cable

The usb dongle can handle input voltages on is data lines without a power supply
(a lot of silicon devices HATE (according to data sheets) to have a voltage
across there inputs that is higher than there power supply.

A of course the wires you are going to solder to the usb dongle?
may not conform to USB specification, but I don't think that that will be your
biggest problem

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