How to display text on 16x2 LCD using AVR microcontroller (ATmega16)

      This article is in continuation to the article Single character LCD display using AVR. The aforesaid article shows how to display a single letter on LCD. Moving forward towards learning to work with LCD, this article explains how to display a string on LCD. Displaying string is occasionally used in many applications.

The connection of the LCD with the AVR microcontroller (ATmega16) is shown in the circuit diagram.

 

#define F_CPU 8000000

#include <avr/io.h>

#include <util/delay.h>

#define dataport PORTA

#define commport PORTD

#define rs PD4

#define wr PD5

#define en PD6

int LCD_init(void);

int LCD_SendData(void);

int wrcomm(void);

int wrdata(void);

int main(void)

{

DDRA = 0xFF; //Setting PortA as output port

DDRD = 0x70; //Setting PortD 4, 5, 6 pin as output pins

LCD_init(); //Initialise LCD

LCD_SendData( ); //Write to LCD

return 1;

}

int LCD_init()

{

dataport = 0x38; //initialize LCD 2 lines, 5x7 matrix

wrcomm(); //Right the command byte to command register

dataport = 0x01; //Clear LCD

wrcomm(); //Right the command byte to command register

dataport = 0x0E; //Display on Cursor Blinking

wrcomm(); //Right the command byte to command register

dataport = 0x80; //Cursor at line 1, position 1

wrcomm(); //Right the command byte to command register

dataport = 0x1C; //Shift Entire Display To Right

wrcomm(); //Right the command byte to command register

return 1;

}

/*********** **** <<Sending Data To LCD Display>> ************ ***/

int LCD_SendData(void)

{

unsigned char j[] = " PROELX TEST";

int i;

for(i = 0; i < sizeof j; i++)

{

dataport = j[i];

wrdata();

}

return 1;

}

/******* <<Righting the command byte to command register>> ********/

int wrcomm(void)

{

commport &= ~(1 << rs); //Setting RS = 0, selecting command register

commport &= ~(1 << wr); //Setting RW = 0

commport |= (1 << en); //EN = 1

commport &= ~(1 << en); //EN = 0, thus giving high to low pulse on Enable pin

_delay_ms(10); //10ms delay

return 1;

}

/********** <<Righting the Data byte to Data register>> **********/

int wrdata(void)

{

commport |= (1 << rs); //Setting RS = 1, selecting data register

commport &= ~(1 << wr); //Setting RW = 0

commport |= (1 << en); //EN = 1

commport &= ~(1 << en); //EN = 0, thus giving high to low pulse on Enable pin

_delay_ms(10) ; //10ms delay

return 1;

}