Cellphone LCDs (color) - again

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Hi all,

I asked here about small LCDs with COG controllers recently, and had some
interesting suggestions, but nothing that directly led me to being able to
prototype my project. After investigating the matter a lot deeper, it seems
like my only option is to repurpose a cellphone display. I'm aware of
numerous projects that involve monochrome LCMs from different phones. But I
need one grayscale LCD and one color LCD. I need at least 4 grays,
preferably 8. Not only are all the projects I can find monochrome, but most
of them use European phones, and it's quite difficult to cross-reference the
numbers with equivalent U.S. models.

I don't mind spending a couple of hundred dollars on these displays if need
be - so it's quite acceptable for me to have to buy and junk a brand-new
cellphone. But I need to be *sure* that I can use the LCD.

Can anyone point me to a homebrew project that will lead me to suitable
cellphone LCDs available in North America? To reiterate my needs:

1 grayscale STN LCD ~1" diag or smaller, 96x64 or so is fine (anything down
to about 48x48 is probably OK). Minimum 4 gray levels.

1 CSTN LCD, at least 2 bits per color component, ~1" diag or smaller, same
kind of resolution requirement as above. This is more important than the
grayscale one, actually.

LCD must have integrated controller. Anything much bigger than about 1.5"
diagonal is too large.

I've found numerous parts that would suit me fine, but they're just not
available as samples. I've also found plenty of sites selling replacement
LCDs for cellphones, but no datasheets for those parts. So I'm kind of
between a rock and a hard place.

Re: Cellphone LCDs (color) - again
On Sun, 02 Nov 2003 01:18:40 GMT, "Lewin A.R.W. Edwards"

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Check out Kopin's CyberDisplays:
(http://www.kopin.com/html/cyberdisplay_-_kopin_microdisp.html ).
These are the right size but higher resolution than you're looking

Re: Cellphone LCDs (color) - again
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Damn! Last time I saw Kopin's stuff was at SID in San Jose in 1999. At the
time it was impossible to get samples. I'm glad to see they've loosened up
now - thanks for pointing me that way.

Unfortunately, microdisplays including Kopin's are not the answer for my
current problem - besides optical difficulties, they require a complicated
drive signal and don't qualify as "on-module controller".

I'm looking to wrist-mount this display, for direct view without intervening

The frustrating thing is, I KNOW the parts I want exist. It's just a matter
of finding them.

Re: Cellphone LCDs (color) - again
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   Lewin, there are several local companies that rebuild cell phones,
and at least one wholesaler who sells the replacement displays for
pagers and cell phones.

I think it is:
Crystal Exchange Inc.
7365 Southwest 38th Street, Ocala, FL 34474
(352) 291-1222

I can call them tuesday, and verify it for you, if you want me to. I
have to spend Monday driving to and from the Gainsville VA hospital, so
I won't have much free time on Monday.  

4551 Northwest 44th Avenue, Ocala, FL 34482
(352) 671-6707

This is the company that does wholesale pager and cell phone repairs.

http://www.scawireless.com/sponsors.htm is a list of some other
companies that deal with cell phone repairs, etc.


Michael A. Terrell
Central Florida

Re: Cellphone LCDs (color) - again
Hi Michael,

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Great, the question being - do they have data on the LCDs? :) There's no
problem finding people who sell LCDs, but you simply tell them a cellphone
model and they ship you an LCD in a box. I need to know that the LCD in
question has an integral controller, and what chip it is, so I can get the
datasheet and have a hope of programming the thing.

(The reason it needs to have an on-chip controller is because I'm
controlling it from an 8-bit MCU without LCD controller).

Re: Cellphone LCDs (color) - again
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   I'll try to find out, next week. From what I understand, they have
service data on the phones, and I think I still know someone who works
there. I was offered a job there last year but I can't handle mandatory
overtime, so I had to turn it down

Michael A. Terrell
Central Florida

Re: Cellphone LCDs (color) - again
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If by complete COG you mean the display with the scanning controller,
I don't think you will be able to find it. Don't take my word for that
though. As for gray levels in passive displays, I have learned this
trick is performed by a kind of time based modulation on pixels
similar to PWM in wich one keeps the pixel on a number of scans out of
16. Same with colour passives. So I don't think it's pratical having
more than 4bpp for passives.

Have you considered a CPLD to performe this video function? I had to
build one for a Z180 based legacy design and it took me longer to
learn VHDL than to implement the design itself though only 1 bit per
pixel. I don't think extending to 4bpp. As long as you know VHDL, it
won't take too long to have the thing running.



Re: Cellphone LCDs (color) - again

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I think you're wrong on this. The monochrome LCDs certainly have integral
scanning controller. In some cases they even use a serial interface
(Ericsson LX588, LX788, related GSM models, etc).

For experiment's sake I opened my Nokia 3595 (96x64 color, pretty much
exactly the device I want) and scoped the signals to the LCD. There doesn't
seem to be a regular line or frame pulse. There are intermittent signals on
several lines, which is probably the phone updating its time display. If I
could find out what controller is on the LCD, I could probably
reverse-engineer the pinout.

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Right, FRM (or at least that's what Epson calls it). On the grayscale model,
I need either 4 or 8 grays; e.g. black, 66%, 33%, white. Not 4 or 8 _bits_
of grayscale resolution :)

The common CSTN cellphone LCDs are 4K colors (4 bits per color component),
which is perfect for me.

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It's not feasible. I don't have time budgeted for developing this function,
and this is a black-box prototype that will have no relationship to the real
hardware, so I'm unwilling to spend lots of time inventing wheels that will
be discarded. Plus, I don't have much experience with VHDL (most of the
projects I've done with CPLDs have been with schematic-entry packages).

The real product would probably use an ASIC/ASSP with a 65C02 or 65C816 core
and on-chip LCD controller, with a custom LCD. But that is not my problem; I
will provide technical advice to the customer and that's *it* - I'm not
getting roped into writing the actual code for the real product, because
they would probably want to pay me on a royalty basis, and I don't believe
this product will be cheap enough to enjoy widespread sales. They want a
QCIF color CMOS image sensor, a color LCD, IrDA connectivity and 1Mb of
internal flash memory for a retail price of $30. I don't believe they will
be able to sell it for less than $100.

I gave the customer an estimate based on the assumption of being able to
source LCDs with on-board controllers. If that turns out to be an invalid
assumption, I'll just cancel the contract. It means throwing away some R&D
time, but that's just a risk of doing business. Hantronics does sell a color
LCD with on-board Epson controller, but it's a bit large for my needs.

Re: Cellphone LCDs (color) - again
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This is perhaps a reach, but for the prototype, you might consider IR'ing
images to one of those wrist cameras:


Re: Cellphone LCDs (color) - again
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A wrist camera is the product I'm prototyping ;) I don't believe they will
cost it down to their target, even with a crappier LCD.

-- Lewin A.R.W. Edwards (http://www.zws.com /)
Learn how to develop high-end embedded systems on a tight budget!
We've slightly trimmed the long signature. Click to see the full one.
Re: Cellphone LCDs (color) - again
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Perhap this is what you need:

SAN JOSE, CA, September 23, 2003 . . . Atmel® Corporation (Nasdaq:
ATML) announced today the introduction of a new family of digital
camera processors that cover the entire market for Digital Still
Cameras (DSC). The AT76C113 family of products integrate all the
functions required to implement digital cameras on to a single chip.
The device performs the functions of capturing, processing,
compressing, displaying, and storing images in flash cards, as well as
controlling camera functionality through the use of an integrated
ARM7TDMI™ processor. In addition, the ARM processor is
responsible for analysis of a scene, through hardware assist, and for
the fine-tuning of image processing algorithms that enable consumers
to take exceptional pictures. AT76C113 devices support all flash card
interfaces including Secure Digital, MMC Multimedia Card,
Memorystick™, Smartmedia™, CompactFlash™, and Atmel
Dataflash® cards. AT76C113 has a direct interface to NAND-flash
devices that allows program code as well as captured media to be
stored in on-board NAND-flash. This potentially eliminates the need
for shipping removable flash cards with a digital camera, which in
turn would reduce end-product cost. In addition, all necessary
peripherals including TV video output, USB, UART and SPI, digital
audio interfaces, and direct interfaces to popular LCDs have been
integrated to minimize the total system cost. Analog to digital and
digital to analog converters have also been integrated to detect,
measure, and recharge batteries, to capture and playback audio without
the need of external components, and to control lens motors. Certain
parts also contain USB hosting is also available on allows cameras to
directly print pictures to photo printers.

All AT76C113 devices support MPEG video multiplexed and synchronized
with MPEG audio at a resolution of 30fps quarter-VGA resolution. They
can also decompress audio files, including MP3, through a
high-resolution digital audio interface. The unparalleled image
processing performance- of 55ms per megapixel, and the compression
speed of 75ms per megapixel, combined with the high transfer rates to
flash cards, can achieve capturing, processing, compression, and
storing of six megapixel images in less than one second with minimal
power consumption. A two-megapixel AT76C113-powered camera can take
over 600 pictures using a pair of regular size Photolithium-type
batteries with strobe and zooming for every shot. Typical camera use
can exceed 1000 pictures per battery.

The family of AT76C113 contains products for low-end cameras limited
to three megapixels and products for high-end cameras from four to six
megapixels. Both low and high-end products are available with and
without USB hosting capability.

Production samples, evaluation boards, software libraries, as well as
full application software are available now. Production is ramping up
now in support of several digital camera manufacturers.

Pricing will be under $8 for quantities of 50,000 parts

Re: Cellphone LCDs (color) - again
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Yeah.... good luck trying to prototype anything around this part, though. I
don't even know who the financial backer of the project is, but I am pretty
sure the idea isn't coming from one of the big names in toys.

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