[gta02-core] Calypso's last dance

Werner Almesberger werner at openmoko.org
Thu Jul 23 13:49:44 CEST 2009

?lvaro Lopes wrote:
> I'm sure we all do. From the beginning.

Good, seems that the party can continue after the ritual burning
of the Glamo ;-)

> And how are we to get that amount of power ? That's almost 11W.
> Even at 1.1A we will be unable to charge battery while USB-powered.

Oh, 3 A is just the peak current, e.g., while transmitting and with
very poor reception. Worst-case average current should be in the
order of 1.1 A and there are probably some options to control that
as well. (E.g., how many of the possible transmit slots we even want
to use.)

> What other baseband chips are found in recent devices ? I see
> infineon has some, but most look like full SoC.

The Qualcomm MSM6xxx series is quite popular. However, they're not
exactly open ...

In any case, phones normally don't use modules but have a chipset
that integrates telephony any the application processing more or
less tightly. Besides the openness issues that frequently raises,
there is also the problem that engineering such a solution is

It starts with the upfront payment chip makers require just to
talk to you, which I've been told is in the order of 1 MUSD. And
then there is all the RF engineering that goes into making that
circuit work smoothlu, which is supposed to cost about the same
amount again, plus of course quite some time.

Joining that exclusive club becomes an option if you have plenty
of money and are selling millions of units. Since we're not quite
there yet, we'll have to do with modules.

Modules aren't meant for phones but for other devices that have a
need to communicate, e.g., the call-the-ambulance automat in your
benz. This means that they're not always as small as we'd like
them and that they may not have precisely the feature set we need,
but some modules look like acceptable compromises.

The Calypso was a unique opportunity for using a chipset instead of
a module, because FIC had already done the initial design and
Openmoko Inc. could just copy that, without paying the development
from scratch.

- Werner

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