Werner Almesberger werner at openmoko.org
Wed Apr 15 06:03:43 CEST 2009

Gerald A wrote:
> BT == Bluetooth?


> >>  - integrate IDBG
> >
> >
> I'm guessing this is a way to unbrick, or a failsafe?

To unbrick and as a debugging aid (serial console, remote reset,
and - for those really nasty cases - JTAG). Once you have a
microcontroller in there, you can also teach it some more tricks
that are useful for things like testing, such as access to I2C or
HDQ, or remote activation of the POWER button.

> What I'm wondering is if there would be a way to slap a small Readonly piece
> in there, which can do a reflash. I know I live in utopia here, but it might
> be one way to do it. Comments?

That's basically what the NOR in GTA02 does. It works quite nicely,
but it only solves the unbricking, not the debugging, and it sits
on the memory bus, so it adds to the capacitative load, which can
limit the maximum memory speed. E.g., GTA02's memory accesses could
be 33% faster is we didn't have NOR and Glamo on the bus. (Okay,
without the Glamo, the LCM would have to be refreshed from main
memory, which basically eats up the speed gain.)

> Question -- is there anything in this form factor which is actually better
> then the Glamo?

Yes, no Glamo at all ;-)) The Glamo is essentially an anachronism.
For that class of devices, graphics acceleration is now implemented
in the CPU. So any external accelerators will either be very
specialized or obsolete.

The 2442 doesn't have a built-in accelerator, but considering that
memory bandwidth between CPU and main memory is more than an order
of magnitude better than between CPU and the Glamo framebuffer, even
unaccelerated graphics would be better in almost all cases than
using the Glamo.

> And, if this one is selected, will we be able to do a field upgrade, or
> would it be another TI GSM firmware upgrade game? (I think not, but just
> asking).

Don't TI GSM firmware upgrades work quite well in the field ? And
yes, upgradeability would be a pretty strong requirement. Once
bitten, ... :)

> Real FPU? No more software floating point? :P

Perhaps a socket for an external coprocessor, 8087-style ;-)

> I remember a lot of questions and suggestions that people be "employed" by
> OM for a nominal amount so they could gain access to the NDA.

That could be one possible approach.

> but if I remember the
> NDA's were for the documentation provided, but not for the derived works
> (meaning an OM "employee" could write a document explaining OM's
> implementation, could write open source drivers and release them, etc).

That depends on the content of the NDA. Of course, only the kind of
NDA that lets one write and release Open Source drivers makes sense
for a project like Openmoko. If there are more freedoms, or if the
information can be obtained without jumping though hoops, that's of
course even better.

- Werner

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