LCD evaluation and other preparations for FC handset

[Serg l]

Excellent!

https://www.thingiverse.com/thing:189940/#comments

Probably should start looking into enclosure design.
I can make small stuff, up to 120x120x300 mm single part.

On Sun, Apr 15, 2018, 7:17 PM Mychaela Falconia <mychaela.falconia at gmail.com>
wrote:

> 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:
>
> https://www.freecalypso.org/members/falcon/pictures/lcd-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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