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I2C LCD Display

I bought an I2C display on ebay and by the description it seemed it just might work out of the box… But it didn't …

Here is a description of how I got it to work, so next time I do not have to invent the wheel again.

My display has a PCB on the back labled “YwRobot Arduino LCM1602 IICV1” but it appears it is the same as the the one of The only difference is the text on the back.

There were a few (simple) steps in getting the display to work, you just need to know what they are.

But first, here is a demo of the LCD display

The Hardware

The display works on an I2C interface. There is a board on the back that takes I2C signals and translates them in to a parallel signal. The display its self is originally a parallel display.

The I2C address is “hard wired” of the address: 0x27 This is something you can't see on the board, you must read it in the provided documentation.

On the back is also a potentiometer, this is for adjusting the contrast. If you never get to see any chars but you were expecting the display to show something, you might want to try to adjust this potentiometer.

The connection to an Arduino (clone) is very simple to;

  • GND to GND (0V)
  • VCC to +5Volt
  • SDA to analog port 4 (PC4 or pin 27)
  • SCL to analog port 5 (PC5 or pin 28)

The software

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