March 24, 2024

Introduction to Interfacing LCD Display with AVR Atmega-328

Displaying information is an integral part of embedded systems, and LCD (Liquid Crystal Display) modules are commonly used for this purpose. In this post, I will guide you through the process of interfacing an LCD display with the AVR Atmega-328 microcontroller. We will cover the basic concepts, connections, and provide extensive examples and explanations.

Understanding LCD Displays

LCD displays are widely used due to their low power consumption and easy integration with microcontrollers. They consist of a series of pixels formed by liquid crystals that act as tiny light valves. These pixels can be individually controlled to display characters, symbols, or graphics.

LCD displays are available in different sizes, from small 16x2 modules to larger ones containing more pixels. The common 16x2 LCD display is a popular choice for beginners, and our examples will be based on this type.

Interfacing Hardware

To interface an LCD display with the AVR Atmega-328 microcontroller, we need to establish both data and control connections. Here is a basic diagram illustrating the connections:

1. Data Connections
   • LCD pins D4-D7 are connected to AVR Atmega-328 pins D4-D7.
2. Control Connections
   • LCD pin RS (Register Select) is connected to AVR Atmega-328 pin D2.
   • LCD pin E (Enable) is connected to AVR Atmega-328 pin D3.

These connections establish communication between the microcontroller and the LCD display. The RS pin is used to select either the instruction register or the data register, while the E pin enables the LCD to latch the data/command provided on its data lines.

AVR Atmega-328 Code Examples

To demonstrate the interfacing process, we will use the Arduino IDE and write code in the C programming language. Below are some examples that cover various LCD operations:

1. Initializing the LCD

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#include <LiquidCrystal.h>

// LCD module connections
LiquidCrystal lcd(2, 3, 4, 5, 6, 7);

void setup() {
  // Set up the number of columns and rows on the LCD
  lcd.begin(16, 2);
}

void loop() {
  // Your code here
}

This code initializes the LCD module by setting the number of columns and rows. Adjust the lcd.begin(16, 2); line according to your LCD’s specifications.

2. Displaying Text

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void loop() {
  lcd.setCursor(0, 0);  // Set the cursor to column 0, row 0
  lcd.print("Hello, World!");

  lcd.setCursor(0, 1);  // Set the cursor to column 0, row 1
  lcd.print("Embedded Systems");
}

This code displays the text “Hello, World!” on the first row of the LCD display and “Embedded Systems” on the second row.

3. Scrolling Text

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void loop() {
  String message = "This is a scrolling message. ";

  lcd.setCursor(0, 0);
  lcd.print(message);

  for (int i = 0; i < message.length(); i++) {
    delay(300);
    lcd.scrollDisplayLeft();
  }
}

This code demonstrates scrolling text on the LCD display. The message scrolls continuously from right to left.

4. Creating Custom Characters

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byte customChar[8] = {
  B00000,
  B10001,
  B00000,
  B01010,
  B10001,
  B01010,
  B00100,
  B00000
};

void setup() {
  lcd.createChar(0, customChar);
  lcd.begin(16, 2);
}

void loop() {
  lcd.setCursor(0, 0);
  lcd.write(byte(0));
}

This example shows how to create custom characters and display them on the LCD. In this case, we create a heart shape and display it on the LCD.

Conclusion

Interfacing an LCD display with the AVR Atmega-328 microcontroller opens up a wide range of possibilities for displaying information in your embedded systems projects. By understanding the basic connections and utilizing simple code examples, you can start integrating LCD displays into your own projects.

Remember to refer to the datasheets of your specific LCD module for the pin connections and command set details. Experiment with other commands and functions provided by the Arduino LiquidCrystal library to fully explore the capabilities of LCD displays. Happy interfacing!

➡️ Flask configuration and environment

⬅️ Testing in Flask

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