Interfacing LCD (4 bit Mode)

This is an example how to interface to the standard Hitachi-44780 LCD using an AT89C51 microcontroller and Keil as C Compiler. I use a standard 16-character by 2-line LCD module, see schematic below. Here, I use 4-bit interfacing.

main.c

#include

#include "lcd.h"

main( )

{

LCD_init();

LCD_row1(); LCD_puts("Hello World");

LCD_row2(); LCD_puts("Good Morning");

while (1);

}

seven.c

#define LCD_en P3_1

#define LCD_rs P3_0

#define LCD_DELAY 2000 /* Delay for 1 ms */

#define LCD_clear() LCD_command(0x1) /* Clear display LCD */

#define LCD_origin() LCD_command(0x2) /* Set to origin LCD */

#define LCD_row1() LCD_command(0x80) /* Begin at Line 1 */

#define LCD_row2() LCD_command(0xC0) /* Begin at Line 2 */

/***************************************************

* Prototype(s) *

***************************************************/

void LCD_delay(unsigned char ms);

void LCD_enable();

void LCD_command(unsigned char command);

void LCD_putc(unsigned char ascii);

void LCD_puts(unsigned char *lcd_string);

void LCD_init();

/***************************************************

* Sources *

***************************************************/

void LCD_delay(unsigned char ms)

{

unsigned char n;

unsigned int i;

for (n=0; n

{

for (i=0; i

}

}

void LCD_enable()

{

LCD_en = 0; /* Clear bit P2.4 */

LCD_delay(1);

LCD_en = 1; /* Set bit P2.4 */

}

void LCD_command(unsigned char command)

{

LCD_rs = 0; /* Clear bit P2.5 */

P2 = (P2 & 0xF0)|((command>>4) & 0x0F);

LCD_enable();

P2 = (P2 & 0xF0)|(command & 0x0F);

LCD_enable();

LCD_delay(1);

}

void LCD_putc(unsigned char ascii)

{

LCD_rs = 1; /* Set bit P2.5 */

P2 = (P2 & 0xF0)|((ascii>>4) & 0x0F);

LCD_enable();

P2 = (P2 & 0xF0)|(ascii & 0x0F);

LCD_enable();

LCD_delay(1);

}

void LCD_puts(unsigned char *lcd_string)

{

while (*lcd_string)

{

LCD_putc(*lcd_string++);

}

}

void LCD_init()

{

LCD_en = 1; /* Set bit P2.4 */

LCD_rs = 0; /* Clear bit P2.5 */

LCD_command(0x33);

LCD_command(0x32);

LCD_command(0x28);

LCD_command(0x0C);

LCD_command(0x06);

LCD_command(0x01); /* Clear */

LCD_delay(256);

}