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Author Topic: I2C LCD **no data sheet** HOW TO CONNECT  (Read 2483 times)
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Hi folks,

I have an arduinoboard and would like to connect a LCD Display.
My local electronic parts shop sold me this one:



BUT they had no data sheet at all. I am clueless how to make it work with arduino. I don t even know where to connect the power for the backlight. Nor do I know how to make it work -> display text with the help of the I2C libraries.

The only thing I know is the numbers on the back:
LCM015 R2.1 SN 102 94V
and a "Kl" maybe a vendor??

Any help is greatly appreciated.
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Possibly the two pads at the immediate ends/edges/corners of the board are for the backlight...possibly.
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Check this site:

http://www.oppermann-electronic.de/html/januar_2008.html

It's in german, but the pinout is explained.

It's basically a standard HD44780 display with a PCF8574 I2C interface IC on board.

"Hintergrundbeleuchtung" is german for backlight, the rest of the pinout should be understandable even for the non german speaking.

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Based on what I could find, this LCD is likely an HD44780 compatible display, but it has an I2C interface in front of that chipset; without a datasheet (I couldn't find anything - a few people asking about it, though), it would be nearly impossible to figure out.

If I were you, I would return it and get your money back - if you can. If not, put the LCD in your box of "get 'round toit" items, and come back in 6 months or a year, and see if anything pops up searching again.

You may just have to chalk it up as "bad luck" (I have a few LCDs that fall into the category myself)...

 smiley
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Well - MikMo has solved a big part of the mystery; from the datasheet for the PCF8574 (http://www.nxp.com/documents/data_sheet/PCF8574.pdf) it looks like there are 3 address set bit lines from the chip (A0-2, pins 1-3) - so you would either have to figure that out, or program the I2C to do the HD44780 setup, and try the 8 different addresses until one of them works...

I'll have to look at my LCDs I picked up that were I2C (IIRC) - maybe they use the same I2C expander chip...

 smiley
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From above link it looks like it uses I2C address  0x4e and it can not be changed.
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Thank you so so much I got the display to light up and with VCC 5v on, it shows black blocks where the letters should be.

Now I don't get the code to run. I use the library:

https://public.me.com/digid

from

http://www.wentztech.com/radio/arduino/files/LCDI2C.html

it has a hello world in its examples.

I am clueless where to copy the "LCDI2C.cpp" and "LCDI2C.h" to!!!
I coped them to :

Code:
localhost libraries # pwd
/usr/share/arduino-0017/hardware/libraries
localhost libraries # ls -la
total 52
drwxr-xr-x 13 root uucp 4096 Aug 27 01:31 .
drwxr-xr-x  6 root uucp 4096 Aug 26 17:10 ..
drwxr-xr-x  3 root uucp 4096 Aug 26 17:10 EEPROM
drwxr-xr-x  4 root uucp 4096 Aug 26 17:10 Ethernet
drwxr-xr-x  3 root uucp 4096 Aug 26 17:10 Firmata
drwxr-xr-x  3 root uucp 4096 Aug 27 01:33 LCDi2c
drwxr-xr-x  3 root uucp 4096 Aug 26 17:10 LiquidCrystal
drwxr-xr-x  3 root uucp 4096 Aug 26 17:10 Matrix
drwxr-xr-x  3 root uucp 4096 Aug 26 17:10 Servo
drwxr-xr-x  3 root uucp 4096 Aug 26 17:10 SoftwareSerial
drwxr-xr-x  2 root uucp 4096 Aug 26 17:10 Sprite
drwxr-xr-x  3 root uucp 4096 Aug 26 17:10 Stepper
drwxr-xr-x  4 root uucp 4096 Aug 26 17:10 Wire
localhost libraries # ls -la LCDi2c/
total 68
drwxr-xr-x  3 root uucp  4096 Aug 27 01:33 .
drwxr-xr-x 13 root uucp  4096 Aug 27 01:31 ..
-rwxr-xr-x  1 root uucp  7359 Aug 27 01:33 LCDI2C.cpp
-rwxr-xr-x  1 root uucp  1822 Aug 27 01:33 LCDI2C.h
-rw-r--r--  1 root uucp 33540 Aug 27 01:33 LCDI2C.o
-rw-r--r--  1 root uucp  4500 Aug 27 01:33 README LCDI2C.rtf
drwxr-xr-x  8 root uucp  4096 Aug 27 01:33 examples
localhost libraries #


but this only get me:

[code]20: error: LCDI2C.h: No such file or directory In function 'void setup()':
Bad error line: -2

on that code
Code:
#include <Wire.h>
#include <LCDI2C.h>

LCDI2C lcd = LCDI2C(2,10,0x4E,1);             // Number of lines and i2c address of the display

void setup() {

  lcd.init();
 
  lcd.print("Hello World!");
}


void loop()
{
  
}

So I feel like I have to install this library differntly. But how?

thank you already :=
[/code]
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Try changing the name of the directory to all upper case, to match the file names.
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I got it to upload correctly. I had to put the libraries into /home/sketchbook/libraries/LCD/

Now I feel like my Display and the libraries don't fit together.

How can I make the Display work? (Do I have to change something in the libraries??)

Thank you
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