LCD Backpack - I2C

HobbyTronics LCD Backpack - I2C
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Manufacturer: HobbyTronics
Average Rating: 5 out of 5 Stars!


LCD Backpack - I2C

The LCD I2C Backpack is a useful little board that can be soldered onto the back of LCD’s that use the standard Hitachi HD44780 compatible interface. This allows the LCD (and backlight if fitted) to be controlled directly from a microcontroller using the I2C interface.

This has a number of advantages

  • Reduces the minimum number of connections needed from 12 (for an LCD with backlight) to only 4 thus saving many input/output pins on the microcontroller
  • Control an LCD using a smaller (less pin count) microcontroller. E.g. 12F1822 (8 pin IC)
  • Simplifies wiring
  • Digital control of LCD backlight brightness
  • LCD Contrast adjustment potentiometer fitted to backpack
  • Allows the connection of multiple LCD displays (up to 4) to one microcontroller

LCD I2C Backpack and Arduino Uno

Suitable for LCD’s with Hitachi HD44780 compatible interface without a backlight and for displays with common Anode LCD backlights. The LCD backpack requires a suitable 5V supply.

The LCD backpack has a default I2C address of 58 but can be set to 58, 59, 60 or 61 via two solder links on the board. The board also has space for I2C pullup resistors if they need to be fitted.

The backpack comes complete with 16-way male header pins for connection to the LCD and both a four pin right angle and a 4 pin straight header for connection to a microcontroller.

Size:  43mm x 26mm

We have created a useful Arduino Library to make using the backpack very easy and also have example code and a library file for the Hi-Tech C compiler. Conversion of these libraries to other languages should be straightforward.


LCD Backpack Datasheet
Arduino Example code (Requires Library below)
Arduino LCD Backpack Library (works with both Arduino 1 and older versions)
Hi-Tech C LCD Backpack Demo and Library

Works with Raspberry Pi

We can confirm that the LCD Backpack works great with the Raspberry Pi. Please note however that Logic Level Conversion should be used as the LCD backpack is designed to run at 5V.


We tested it out using a 20x4 LCD display and the following commands.

	// Turn Backlight on (value 0xF0)
	i2cset -y 0 0x3A 0x07 0xf0
	// Set display type to 20x4
	i2cset -y 0 0x3A 0x05 0x04 0x14 i
	// Print Hello
	i2cset -y 0 0x3A 0x01 0x48 0x65 0x6C 0x6C 0x6F i
	// Move to line 2 position 1
	i2cset -y 0 0x3A 0x02 0x02 0x01 i
	// Print Hello again
	i2cset -y 0 0x3A 0x01 0x48 0x65 0x6C 0x6C 0x6F i



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LCD Backpack - I2C
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LCD Backpack - I2C
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LCD Backpack - I2C
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LCD Backpack - I2C
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LCD Backpack - I2C
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LCD Backpack - I2C
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