How to interface a 16*2 LCD display with atmega8

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Today we are going to discuss about the LCD interface with the atmega8 micro-controller.

Pin Configuration of ATMEGA8

16*2 LCD display

Schematic diagram of LCD interface with ATMEGA8(click on image-full size view )

Configurations

Here,PORTB(PB0-PB7) set as data port in 8 bit mode LCD display.Connect D0-D7 with the PORTB.

• Ground the first lead of the lcd(vss) display.
• Connect vcc to a 5v power supply.
• Conncet VEE with a pot.It's used to adjust the contrast of the LCD display

 15th and 16th leads are used to power the back light of the LCD.Connect 15th with 5v and ground 16th lead.

C CODE

#define F_CPU 1000000
#include <avr/io.h>

void delay(unsigned char);

//Main Code

int main()
{
DDRB=0xff;    //set PORTB as out put
 
  DDRD=0b01110000;   //Set PD.4,5 and 6 as Output
 

/*
RS=PD5

           R/W=PD6
         
           E=PD4          */

  //Give Inital Delay for LCD to startup as LCD is a slower Device
  delay(2);

  init_lcd();

while(1)
    {

       
           
   lcd_cmd(0x80);       //Goto Line-1,first position
  lcd_send_string("WELCOME TO! ");

   lcd_cmd(0xC0);      //Goto Line-2, first position    

   lcd_send_string("EGLOB :) ");
   lcd_cmd(0x01);     //Clear the lcd
   delay(1);
      

}

} 

//LCD function
/*------------------------------------------------------------------------------------------------------------*/

//Function for sending commands to LCD
void lcd_cmd(unsigned char command)

{
 

//Put command on the Data Bus
  PORTB = command;

  //Enable LCD for command writing
  PORTD = 0b00010000;

  //Allow delay for LCD to read the databus
  delay(1);

  //Disable LCD again
  PORTD = 0b00000000;

  //Allow some more delay
  delay(1);
}

//Function for sending Data to LCD
void lcd_data(unsigned char data)

{
  //Put data on Data Bus
  PORTB= data;


  //Set R/S (Regiter Select) to High, and Enable to High
  PORTD = 0b00110000;

  //Allow for delay
  delay(1);

  //Disable LCD again
  PORTD = 0b00100000;

  //Allow for some more delay
  delay(1);
}

//Function to send String to LCD

void lcd_send_string(char* string)

{
  while(*string)

{
  //Send value of pointer as data to LCD
  lcd_data(*string);
  //Increment string pointer
  string++;
  }
}




//Function to Initilise LCD

void init_lcd()

{
  //Setup both lines of LCD
  lcd_cmd(0x38);
  //Set Cursor off - Enable LCD
  lcd_cmd(0x0E);
  //Clear Screen
  lcd_cmd(0x01);
  //Goto first position
  lcd_cmd(0x80);
}

 /*----------------------------------------------------------------------------------------------------------*/

//Delay function

void delay(unsigned char dtime)
{
int i,j;
for(i=0;i<=dtime;i++)
{
for(j=0;j<5000;j++);
}}

//You can use your own delay functions and replace this delay function with your code
/*-----------------------------------------------------------------------------------------------------------*/


Feel free to ask your doubts..

ENJOY!