LC Display "EA T123A-I2C" on Arduino Uno no function

Other Hardware Displays
1

Hello,
my LC Display with I2C does'nt give a sign on Display.
I have an Arduino UNO w/ "I2C LCD" Lib,and uploaded,and I become not a Sign on Display.
I have changed
LiquidCrystal_I2C lcd(0x20,16,2); // set the LCD address to 0x20 for a 16 chars and 2 line display

to LCD address 0x4a (datasheet) and 12 chars and 3 line.
and nothing happen
When I turn the Contrast Potentiometer than appear all pixels.

2

In order for us to determine if you are interpreting things correctly (such as the I2C address) we will need a link to the appropriate datasheets.

In order for us to determine if you are correctly implementing what you are interpreting then we will need to see your code.

Otherwise all you will get are guesses and good intentions.

Don

3

Hello,
the code is :

#include <Wire.h>
#include <LiquidCrystal_I2C.h>

#define BACKLIGHT_PIN 13

//LiquidCrystal_I2C lcd(0x27); // Set the LCD I2C address I have changed the Address 3A (after I2C Scan)

LiquidCrystal_I2C lcd(0x38, BACKLIGHT_PIN, POSITIVE); // Set the LCD I2C address

// Creat a set of new characters
const uint8_t charBitmap[][8] = {
{ 0xc, 0x12, 0x12, 0xc, 0, 0, 0, 0 },
{ 0x6, 0x9, 0x9, 0x6, 0, 0, 0, 0 },
{ 0x0, 0x6, 0x9, 0x9, 0x6, 0, 0, 0x0 },
{ 0x0, 0xc, 0x12, 0x12, 0xc, 0, 0, 0x0 },
{ 0x0, 0x0, 0xc, 0x12, 0x12, 0xc, 0, 0x0 },
{ 0x0, 0x0, 0x6, 0x9, 0x9, 0x6, 0, 0x0 },
{ 0x0, 0x0, 0x0, 0x6, 0x9, 0x9, 0x6, 0x0 },
{ 0x0, 0x0, 0x0, 0xc, 0x12, 0x12, 0xc, 0x0 }

};

void setup()
{
int charBitmapSize = (sizeof(charBitmap ) / sizeof (charBitmap[0]));

// Switch on the backlight
pinMode ( BACKLIGHT_PIN, OUTPUT );
digitalWrite ( BACKLIGHT_PIN, HIGH );

lcd.begin(20,4); // initialize the lcd

for ( int i = 0; i < charBitmapSize; i++ )
{
lcd.createChar ( i, (uint8_t )charBitmap );*

  • }*
  • lcd.home (); // go home*
  • lcd.print("Hello, ARDUINO "); *
  • lcd.setCursor ( 0, 1 ); // go to the next line*
  • lcd.print (" FORUM - fm ");*
  • delay ( 1000 );*
    }
    void loop()
    {
  • lcd.home ();*
  • // Do a little animation by writing to the same location*
  • for ( int i = 0; i < 2; i++ )*
  • {*
  • for ( int j = 0; j < 16; j++ )*
  • {*
  • lcd.print (char(random(7)));*
  • }*
  • lcd.setCursor ( 0, 1 );*
  • }*
  • delay (200);*
    }
    [/quote]
    But it doesn't work.I can only change the Contrast uptil the small boxes are fully pixeled.
    Thanks
4 
//LiquidCrystal_I2C lcd(0x27);  // Set the LCD I2C address I have changed the Address 3A (after I2C Scan)

LiquidCrystal_I2C lcd(0x38, BACKLIGHT_PIN, POSITIVE);  // Set the LCD I2C address

Which one is right?

Did you miss this part?
"In order for us to determine if you are interpreting things correctly (such as the I2C address) we will need a link to the appropriate datasheets."

Also - please go back to your previous post and change the 'quote' tags to 'code' tags.

Don

5

Which i2c lcd library are you using?

The only library that I've seen that uses a constructor like the one you are using
is in fm's library: https://bitbucket.org/fmalpartida/new-liquidcrystal/wiki/Home
but for that library the constructor takes bit numbers of the output port on the PCF8574
not Arduino pin numbers, so 13 is not a valid choice.

Then the code uses the "backlight pin" as an adruino pin.

In order to help you, we need to know the library you are using and how
the PCF8474 is wired up to the LCD pins.
(different vendors boards wire them up differently)
This is why Don was asking for datasheets.
So you need to disclose which library you are using and
what i2c to hd44780 adapter board you are using.
Please provide links to the i2c lcd product and library.

--- bill