Hi all.
This is only my second post so please have mercy if I'm doing something wrong around here...
I salvaged this LDC screen (monochrome I suppose) that seems to have some interface on board. I would love to be able to control this LCD to learn more about them. I have to mention that I have a bunch of them gathered throughout the time, different sizes and pin configuration waiting for the right moment to try to connect them and see if I can display at least a dot 
I tried to find some information on Internet but could not find any.
The good thing of this small LCD is it has the breadboard friendly pins and more than this it has the pins marked (which usually you don't see it). Before I get to understand how the big screens are driven I would like to begin with these small ones no matter how hard it would be.
Could you please give some ideas or hints with what could I start, if there is any library for this, what protocol of communication could be using given the marked pins,how to connect it, what voltage it uses, anything that might help me make it work. I read somewhere here that is a pain in a@@ to drive these LCDs but I would like to give another step to this challenge.
The pins are: /CS, /WR, DATA, VSS, VLCD, VDD
By the way, another question, could you please put in some simple words what is the difference between VSS and VDD, I've seen somewhere a good explanation that I forgot.
Thank you in advance.
P.S.: I attached two pictures of the LCD in question.
http://www.w-display.com/uploadfile/20110302215631182.pdf
VDD = V+
VSS = GND
VLCD = voltage to drive the LCD
DATA = your data signal
WR = write clock
CS = chip select
It's probably more trouble than it's worth to figure out what the data format is if you don't have a datasheet to go with the part.
Looking up the part number gives nothing on Google so it's a custom chip that is not intended for use outside of products made by the company that made the thing it came out of.
The first thing to do to figure it out is see how many segments there are on it. Since there's a single CS bit, that means the most you can divide that number by is 2. That will give you the number of bits that your data line probably takes.
Provided they didn't do anything crazy, you just need to shove out individual bits with CS set to 0 and 1 and see what lights up.
If there are 32 segments on the display then divide by 2 gives you 16 bits per CS value which is 2 bytes to set which segments you want to light up.
“Don't believe everything you read on the Internet.”
― Abraham Lincoln
I did not touch yet the LCD because I still have unclear aspects.
Let me see if I understand it clear until now. So this LCD can not have "a pixel lit" like I said before. It has digits of 7 segments and maybe other symbols that you called segments also, right? If it is so, I have to scratch my head and ask a few more questions:
What is the communication protocol to use or if is there some library that could use for it, 7 segments or similar?
What is the voltage to put on VLCD? I read somewhere that these LCDs run on 1.5V... Is this so or how?
For data signalling I would use 5V or do I need a level shifter? (either 3.3 or 1.5)
So far I have this configuration. 5V coming from a laptop USB. With a 3.3V voltage regulator I power VDD and through a pot as resistor divider I power the VLCD pin.
I tried to light up something with /WR on ground and moving pins DATA and /CS between + and - 3.3V. Nothing happened. Am I too far from the correct approach? Should I go with some Arduino code? If yes, I don't know what way.
Really nobody done this here? I hurts to see this screen been thrown away when you know it could be used to some Arduino project even if only to display temp and humidity values read from an outside sensor...
Can somebody give me a clue on what to do next because I'm stuck. Or if there any other place to learn more about? I am just trying to learn something that could be useful.
Thanks in advance.
