Hello FC community,

An update on the FreeCalypso handset project: I am still in the process
of evaluating candidate LCDs from different vendors.  All of the
candidate LCD manufacturers I am evaluating are based in Shenzhen,
China - that city seems to be the world capital for fast-turn
electronic design and manufacturing - and in the present case it is
home to a large number of different LCD manufacturers.

The only LCD I have successfully tested so far (as in got to the point
of displaying pictures) is the one from Startek, model KD020C-2A -
Startek was the first vendor to send me usable sample pieces, and they
included a breakout board that made it much easier for me to assemble
a working test rig.  Here are some pictures of this test rig:


The test rig consists of the LCD itself, the LCD vendor's breakout
board, one of our FT2232D boards for interfacing and a rat's nest of
wires connecting the LCD breakout board to the FT2232D board; the
whole mess is mounted on a 6x12" sheet of acrylic material with
double-sticky tape.  The only outside connection to this whole
arrangement is USB on the FT2232D adapter board, used for both power
and programming: as soon as USB is plugged in, the LCD backlight
lights up as it is powered directly from USB 5V through a resistor in
series with each LED.  I programmed the EEPROM on the FT2232D board
with my own USB ID so the connected USB host won't treat it as a
serial device (it is not a serial device - I am using the FT2232D chip
in the so-called MCU host bus emulation mode, which is completely
different from serial or SPI/JTAG), and in order to talk to the
controller inside the LCD module and put pictures on the LCD, I run a
special test program based on libftdi (published in the
freecalypso-hwlab Hg repository on Bitbucket) that issues the
necessary LCD controller commands through the FT2232D running in
FTDI's MCU host bus emulation mode.

The original KD020C-2A LCD had 12:00 viewing direction which we don't
want (it is the opposite of the direction from which cellphone LCDs
are meant to be viewed), but the sample pieces which Startek sent me
are a modified version - it has been modified with some special film
that somehow improves the viewing angle.  I don't really understand it
myself, but most of the test pictures I have tried displaying actually
look better on this LCD from the 6:00 viewing direction (the one we
want for the cellular handset application) than from 12:00.  Overall
the picture quality is very good, and this LCD from Startek would
definitely make a good choice for our FreeCalypso handset product.  It
is definitely better than the LCD on the Pirelli DP-L10, and my S.O.
says that the picture looks even better than on her Nokia phone.

As a matter of due diligence though, I do need to evaluate one other
LCD from a different vendor before we officially commit to using
Startek LCDs.  According to both the LCD datasheet and the vendor's
communication with me, the other vendor's LCD is officially made for
the 6:00 viewing direction, whereas Startek's LCD was originally
12:00, but then modified in some way which I don't really understand.
It is possible that Startek's LCD with their special film is so good
that it's even better than the other vendor's LCD made for 6:00, but I
need to see both with my own eyes before I can commit to anything.

The other vendor in question already sent me their sample pieces, and
they are supposed to arrive on Monday California time.  But they don't
have a breakout board similar to Startek's for their different
connector, so I will need to make my own test PCB.  I plan on still
using an external FT2232D breakout board rather than incorporating the
FT2232D into my own test board - this way the test board will be
simple enough for me to lay out myself.  I'm going to give pcb-rnd a
try on this LCD test board - I have previously used gEDA/PCB, but
pcb-rnd has been making great progress and might be suitable for doing
the actual handset motherboard layout way down the road, so I'm
thinking of trying it out for the very simple board.  I'm hoping to do
this layout some time this coming week, and then it will probably be
another 2-3 weeks to actually get the PCB made - but it is needed so
we can properly evaluate both LCD vendors and make a fully informed
decision.  Stay tuned for further updates.

Hasta la Victoria, Siempre,
Mychaela aka The Mother
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