How to interafce 16x2 LCD with AVR microcontroller (ATmega16)

LCD is used to present textual information to the users. It is great fun to work with LCD. Also LCD makes your application more interactive. LCD comes in various configurations and the most popular one is 16x2 matrix display. This article shows the interfacing of ATmega16 with LCD by displaying a simple character on the LCD.

In this project LCD is working in 8-bit mode i.e., the data transferred to the LCD must be in 8-bit data form. The PortA of ATmega16 is connected to data pins of LCD and is defined as LCD_DATA. PortB is defined as control pins (Rs, R/W and En).

Conceptually, interfacing LCD with AVR microcontroller is similar to that of interfacing it with any other microcontroller.
The following steps explain in detail how LCD can be interfaced with ATMEGA 16:

Step1: To initialize LCD
The following instructions are used to initialize LCD.

0x38 to initialize LCD in 8-bit mode

0x01 to clear LCD
0x0E to make cursor ON
0x80 to go to first line and 0th position in LCD

 Delay of around 50 micro second is necessary b/w two commands for execution of instructions.

 void init_LCD(void)
{
LCD_cmd(0x38); // initialization of 16X2 LCD in 8bit mode
_delay_ms(1);

LCD_cmd(0x01); // clear LCD
_delay_ms(1);

LCD_cmd(0x0E); // cursor ON
_delay_ms(1);

LCD_cmd(0x80); // ---8 go to first line and --0 is for 0th position
delay_ms(1);
return;
}

Step2: Define command function

To send any command to LCD
Transfer the command to LCD_DATA port
Set RS and RW bit to go LOW and enable as HIGH
Give a small delay
Set enable to LOW

 void LCD_cmd(unsigned char cmd)
{
LCD_DATA=cmd;
ctrl =(0<<rs)|(0<<rw)|(1<<en); // RS and RW as LOW and EN as HIGH
_delay_ms(1);
ctrl =(0<<rs)|(0<<rw)|(0<<en); // RS, RW , LOW and EN as LOW
_delay_ms(50);
return;
}

 
Step3: Define write function

To display any data on LCD
Transfer the data (Ascii value of the character to be sent) to LCD_DATA port.
Make RW as LOW and set RS and enable as HIGH.
Give a small delay.
Make enable pin LOW

void LCD_write(unsigned char data)
{
LCD_DATA= data;
ctrl = (1<<rs)|(0<<rw)|(1<<en); // RW as LOW and RS, EN as HIGH
_delay_ms(1);
ctrl = (1<<rs)|(0<<rw)|(0<<en); // EN and RW as LOW and RS HIGH
_delay_ms(50); // delay to get things executed
return ;
}

Main Parts:  

LCD

LCD (Liquid Crystal Display) screen is an electronic display module and find a wide range of applications. A 16x2 LCD display is very basic module and is very commonly used in various devices and circuits. These modules are preferred over seven segments.




ATmega16


ATmega16 is an 8-bit high performance microcontroller of Atmel’s Mega AVR family with low power consumption. Atmega16 is based on enhanced RISC (Reduced Instruction Set Computing) architecture with 131 powerful instructions. Most of the instructions execute in one machin.




Circuit Diagram:

Source Code:

Click Here To Download Source Code

 How to interafce 16x2 LCD with AVR microcontroller (ATmega16)