D. Shalnoff shaln...@openmailbox.org wrote:
by the way, is there no finished gerbers in wiki or
repositories? Is anybody have a last version of GTA02 PCB files?
To the best of my knowledge, they were never released publicly - which
is why I'm looking into the possibility of recovering that PCB layout
by reverse engineering.
But I just got an idea: unlike modem firmware and documentation etc,
the PCB layout must have been 100% Openmoko's own original work.
Including the modem section: at the schematic level it's an almost
verbatim copy of TI's Leonardo, but the layout is clearly Openmoko's
own, as the component placement is quite different between TI's and
Openmoko's versions. Compare the pictures and judge for yourselves:
http://ifctfvax.Harhan.ORG/FreeCalypso/leoquad.html
http://wiki.openmoko.org/wiki/File:Gta02a6_comms_chips_under_shield.JPG
If the GTA02 PCB layout is indeed Openmoko's own and did not come from
any third party (along with NDAs etc), then in all practical terms that
intellectual property belongs personally to Sean Moss-Pultz - and if
he could be convinced to release it, he should be fully within his
right to do so, not constrained by any third-party agreements.
I'm going to compose the request to Sean M-P, and Cc it to the list as
an open letter.
To put the present quest into context, I am currently seeking to build
my own Calypso GSM modem hardware:
http://ifctfvax.Harhan.ORG/FreeCalypso/
I seek to build a modem just like the one in the GTA02, but quadband
instead of triband. The hw change from triband to quadband is very
simple: replace the discrete antenna switch and Rx SAW filter
components (see U401 through U404 on the publicly released component
placement drawing) with the quadband integrated RF FEM that was used
on the Leonardo. (Part made by Epcos in the long-bygone days,
currently sourced on the Chinese surplus market along with all other
components of the Calypso chipset.) Plus maybe some changes to the RF
impedance matching networks surronding that block.
I already got TI's reference schematics, the same ones that FIC must
have used as their starting point: found them on 52rd.com back in 2011.
Ditto for the BOM data. If Sean is not willing to release the GTA02
PCB layout and reverse engineering proves to be too expensive, I will
bite the bullet and have my regular PCB layout partner create a new
layout from the schematics and the component placement chart. But my
concern is that neither I nor my PCB layout partner are GHz RF experts,
so if we create our own layout, it may perform poorly and we might be
on a wild goose chase debugging it, respinning the board 3 or 5 times
trying to get it to work... Thus having the GTA02 PCB layout as a
reference would be very helpful to our project. (Other Calypso phones
like my beloved Pirelli would serve poorly as a layout reference: there
are no corresponding schematics, and the component placement is nowhere
close to what we would like to have in a reusable modem module. But
the GTA02 modem fits in one nice rectangle, perfect for modularization.)
And to restate my original inquiry, I am still looking to buy one or
more GTA02 bare boards (no case or display), either working or dead.
SF
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