The D-Sample is here
Spacefalcon the Outlaw
falcon at ivan.Harhan.ORG
Thu Aug 27 19:52:34 CEST 2015
Hello FC community,
The D-Sample kit from TI circa 2002 which I snarfed from a seller in
Singapore (a seller who had no clue what it was :) arrived in my hands
yesterday. I have yet to make the special power cable needed in order
to power it up, but I was already able to make the following
observations from a visual examination of the underside of the board
where the core chipset resides:
* As I expected and feared, the RF section is the not-usable-to-us
Clara-based version. It consists of a TRF6150 transceiver (Clara),
a big shiny Samsung chip that is the external Tx VCO needed with
Clara (but not with Rita, hence not present in the newer designs we
are familiar with), an RF3110 PA and a triband RF FEM (integrated
antenna switch with Rx SAW filters). As far as I know it is exactly
the same RF section as in TI's earlier Ulysse/Nausica/Clara
reference design, predating Calypso.
* The ABB (analog baseband) chip is Iota and not Nausica - good, as in
matched my expectations.
* Now for the kicker: the main DBB (digital baseband) chip is labeled
HERCROM400G2 (the official name of the chip much more popularly
known by its nickname Calypso), so it is Calypso - but not the same
Calypso as the one we are used to. Looking carefully at the imprint
on the top of the IC package, I saw this identifying number:
F741979BGHH. The number rang a bell for me, so I re-read our
Calypso chip docs (found back in 2011 and available on our FTP site)
to refresh my memory. And sure enough, the DBB chip on this
D-Sample board is a much earlier version of the Calypso than the one
we are used to working with.
To the best of my knowledge, the range of Calypso chip versions that
have existed over time is as follows:
* Calypso C05 rev A: the oldest one, full of bugs, DSP ROM version 33,
apparently used in the legendary TSM30 (which I've never seen with
my own eyes), CHIPSET 7 for TI's fw build system.
* Calypso C05 rev B: this is the F741979B found on the D-Sample board
I got. TI's fw build system calls it CHIPSET 8. Going by the
available docs, it is still Calypso C05 with all of its limitations,
still has DSP ROM version 33 (no possibility of AMR or Melody E2,
possibly other advanced audio features missing too), and has only a
few of the worst hw bugs fixed.
* Early Calypso C035 with DSP ROM version 34: never seen one with my
own eyes, but they must have existed. Calypso C035 is CHIPSET 10,
which is what TCS211 firmware is meant to run on.
* Late Calypso C035 with DSP ROM version 36, 751992A in the chip part
number: this is the Calypso chip version in our familiar Openmoko
and Pirelli phones (Compal phones have its "Lite" sibling with half
the internal RAM), i.e., this chip version is what we really mean
most of the time when we casually say "Calypso".
I knew all along that D-Sample was one of the earliest designs which
TI had built with the Calypso, but I didn't know that it was old
enough to have used Calypso C05 rather than C035. Now I know. :)
I can only assume that TI later built D-Sample boards with Calypso
C035 (maybe even the DSP 36 version) populated, as it's only a matter
of populating a different part (same footprint and pinout) onto the
same PCB, but the board I got appears to have been built in 2002 and
untouched since - so it must be an early D-Sample.
Back to practical matters, the practical value of this D-Sample find
for our FreeCalypso work is approximately zero. :( It would be insane
to invest the time and effort into making our loadtools work with the
earlier boot ROM version found in Calypso F741979B, and making changes
throughout the rest of the firmware to work with CHIPSET 8, DSP 33
instead of CHIPSET 10, DSP 36, and then we would still have a show-
stopper with Clara RF for which we have no reference firmware driver
at all, neither source nor object form. Replacing the Calypso chip on
the board with the correct newer version might be at least somewhat
possible (same footprint and pinout), but Clara and Rita RF designs
are absolutely not interchangeable.
So this D-Sample kit I've managed to find and obtain is merely a
souvenir, a piece of TI GSM chipset history. But hey, considering how
much of my life I've invested into this obscure world of TI GSM
chipsets, I think it's OK for me to own this unique piece of history. :)
I am still going to build the power cable so I can try powering this
board up - I am curious to see if it came with any working fw image at
all in its flash. And I am putting exactly the same type of power
input connector on our own FCDEV3B board (TI appears to have used it
on Leonardo as well, but then switched to a different type from
E-Sample onward), so the power cable won't go to waste. :) And yes,
the work toward our own FCDEV3B board is still ongoing.
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