How to Interface the 8051 MCU with an LCD Display

Danielle Gruber
17 min readJan 21, 2022

In this tutorial, we’ll interface the 8051 microcontroller with an LCD (Liquid Crystal Display) and display a blinking “Hello World” message.

Table of contents

· Table of contents
· Introduction
· Hardware setup
· Understanding the LCD
LCD pins
LCD registers
LCD memory
· Using the control pins
Timing of the write cycle
Putting it all together
· Assembly refresher
For loops
Infinite loops
· Code breakdown
Assigning symbolic names
Define data and commands
Define delay subroutine
Define subroutines to send data and commands to LCD
Define byte-looping subroutine
Define main program
Full code
· About the author
· Sources cited and further reading


Several months ago I knew nothing about electronics. Now I’m an electrical engineering major. Why? you might ask. If you’ve read any of my articles on Medium, you may know I’m a neuroscience and brain-computer interface enthusiast. While I headed into university thinking I’d study physics, I realized engineering would be more practical. Plus it’s super fun!

As I’m now delving into the world of computer engineering, I thought I’d take you along in a series of tutorials on programming the 8051 microcontroller using Assembly.

You can view my complete compilation of tutorials in this Github repository, and the code for this tutorial in this folder. Since I’m on break from…

Danielle Gruber

👋 I am a freshman at Yale University majoring in electrical engineering. I’m interested in neuroscience, computer science, math, and everything in between!