Interfacing 8051 with LCD (4 bit Mode)

Interfacing LCD in 4 bit mode with 8051 microcontroller.

This is an example how to interface to the standard Hitachi-44780 LCD using an AT89S51 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 <at89x52.h>

#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<ms; n++)

      {

              for (i=0; i<LCD_DELAY; i++); /* For 1 ms */

      }

}

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);

}



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