FreeCalypso hardware

Mychaela Falconia falcon at ivan.Harhan.ORG
Wed Feb 3 23:06:37 CET 2016

Hello FC community,

The latest tangible artifact in the quest for our own FreeCalypso
hardware is contained here:

It's a ZIP package with gerber files inside; the Free Software tool I
use to view them is this one:

As the README file in the ZIP with the gerbers says, the design is
still a little unfinished.  About 16 hours ago I sent the latest set
of change requests (set of needed changes relative to what's in the
20160202 gerbers) to my off-list contact at the anonymous company who
did this design, and I'm hoping to get another update from them with
these changes in another few weeks.  Then maybe another one or two
review iterations, and then the design should be finished.

The board which these anonymous off-list people are designing for us
is called FCDEV3B, which stands for FreeCalypso development board,
triband, and their design strictly follows my design specification.
It will be a standalone Calypso GSM modem on a 90x50 mm bare board
with the following features:

* A power input connector taking battery-emulating DC power: it's a
  special connector and the power supply needs to provide the right
  voltage and current, but complete kits will be shipped with a power
  supply brick (same size as a small laptop AC power adapter) to run
  the kit on AC mains power.  (Yes, the AC power brick I've selected
  does accept the full international AC voltage range, and it has the
  same AC power input connector as desktop PC power supplies, so it'll
  work no matter where you are in the world. :)

* Both Calypso UARTs brought out on a header connector - 2.8V logic
  levels on an ad hoc connector, but once again complete kits will be
  user-friendly: they will include an off-the-shelf FT2232 USB dual
  UART adapter board along with the necessary custom ribbon cable to
  connect to the FCDEV3B; when using this adapter, the FCDEV3B target
  will become a single USB device presenting two /dev/ttyUSBx
  interfaces corresponding to Calypso's two UARTs.

* Of use to hackers who wish to get in deeper, JTAG and MCSI interfaces
  will be brought out on additional headers.

* There will be a SIM socket on the board, along with a loudspeaker
  and a microphone for exercising voice calls and Calypso DSP audio

* There will be an SMA connector for the GSM antenna; complete kits
  will be shipped with a 5 cm long antenna of the right kind.

* The core modem design is based on the one from Openmoko GTA02, hence
  all FreeCalypso software offerings are expected to work just as well
  on this board as they do on the GTA02 - the intent is for our board
  to fully supplant and eliminate the need for historical Openmoko

* In one noticeable departure from Openmoko's original though, we'll
  be populating a different flash+RAM chip onto the same footprint to
  get more memory of both kinds: 16 MiB of flash and 8 MiB of XRAM,
  the maximum possible in a Calypso design.

Once the FCDEV3B design is fully finished, we get the boards built and
the first board is successfully brought up and running in my lab,
FCDEV3B kits described above will be made available to the general
public on a retail basis.  The retail price for the general public is
expected to be somewhere around $750 USD (quantity 1), but FreeCalypso
project developers and contributors will get subsidized boards -
either totally zero cost or a reduced cost depending on how the
physical PCB fabrication step ends up being financed - there are still
a few unknowns being worked out.

Anyone who buys one of these FCDEV3B kits when they become a reality
will be able to do the following with it:

* Run any of our software offerings: either TCS211-based firmware that
  is 100% functional but is laden with binary blobs, or the gcc-built
  one that is full source, but still partially broken.  And as
  explained here previously, FCDEV3B will be the ideal platform for
  doing the work to make our full-source gcc-built gsm-fw function no
  worse than the blob-laden version.

* OsmocomBB should run just fine on our board too - they don't use the
  flash or XRAM, so our board should be indistinguishable from the
  existing gta0x target to their software - but if all you want to do
  is run OsmocomBB, a dirt-cheap Mot C1xx is all you need, no need to
  spend money on an expensive FreeCalypso board.

* The main advantage of our expensive FCDEV3B compared to existing
  cheap hardware like Mot C1xx is the ability to exercise the *full*
  functionality of TI's GSM firmware, just like on Openmoko's modem.
  There will be TWO serial interfaces, not one; when using the FT2232
  adapter (to be supplied with full kits) and TCS211 firmware, there
  will be a standard AT command interface on /dev/ttyUSB0 and TI's
  RVTMUX interface (the one that works with rvinterf, fc-shell,
  fc-fsio etc) on /dev/ttyUSB1.  The AT command interface on
  /dev/ttyUSB0 will include CSD, fax and GPRS functions like it does
  inside Openmoko's Freerunner - but this time brought out directly to
  the external user, and on hardware that will be made new and readily
  available unlike Openmoko's!

* With any of our FreeCalypso firmwares, one will be able to control
  the modem with AT commands (either plain ASCII on /dev/ttyUSB0 or
  fc-shell on /dev/ttyUSB1), send and receive SMS this way, and make
  and receive voice calls using the on-board loudspeaker and mic.

Of course the complete design of our hardware is free to the world
with nothing withheld - as you can see, I already post work-in-progress
gerber file sets on our FTP site as I receive them from my off-list
contact, and the final gerbers that will be sent to fab will be
published as well.  The complete MCL+netlist source (a non-graphical
form of the design at the "schematic" level) is also posted on the FTP

One big fly in the ointment is that there presently exist NO Free
Software PCB design tools that can handle a board design of this
complexity, hence the FCDEV3B PCB design is being done in one of those
evil proprietary ECAD packages.  There were discussions on this list
last year about me wanting to take a detour from the "main" direction
of FreeCalypso to work on creating an improved version of GNU PCB that
could do what we need, but it's all water under the bridge now: an
anonymous company with an interest in our FreeCalypso project stepped
forward to do the board design I wanted using their choice of software
(Altium Designer), and we are NOT going to throw it out.  But at least
the final gerber output from the proprietary tool is in a publicly
documented industry standard format with a Free Software viewer

Hasta la Victoria, Siempre,

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