Tag Archives: HD44780

chipKIT Tutorial 4: Interfacing a character LCD

Liquid Crystal Displays(LCDs ) are a very popular output device for displaying graphical and alphanumeric data in microcontroller based systems. They can also provide an interactive input interface to the users. The most common type of LCD controller used by hobbyists is the Hitachi 44780, which provides a relatively simple interface between a processor and an LCD. The purpose of this tutorial is to describe how to interface Hitachi 44780–based LCDs with the chipKIT Uno32 board to display alphanumeric information.

Interfacing an Hitachi 44780 based character LCD

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Lab 4: Interfacing a character LCD


HD44780 based LCD displays are very popular among hobbyists because they are cheap and they can display characters. Besides they are very easy to interface with microcontrollers and most of the present day high-level compilers have in-built library routines for them. Today, we will see how to interface an HD44780 based character LCD to a PIC16F688 microcontroller. The interface requires 6 I/O lines of the PIC16F688 microcontroller: 4 data lines and 2 control lines. A blinking test message, “Welcome to Embedded-Lab.com”, will be displayed on the LCD screen.

Required Theory

All HD44780 based character LCD displays are connected through 14 pins: 8 data pins (D0-D7), 3 control pins (RS, E, R/W), and three power lines (Vdd, Vss, Vee). Some LCDs have LED backlight feature that helps to read the data on the display during low illumination conditions. So they have two additional connections (LED+ and LED-), making altogether 16 pin. A 16-pin LCD module with its pin diagraam is shown below.

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