Interfacing 16x2 LCD | AT89C51

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I am using the AT89C51 to interface the 16x2 LCD Display. It will be a minimal display message.
The tools I will be using are :

  • Keil uVision 5
  • Proteus 8 Professional

The LCD is operated in 8 bit mode to display two lines of messages under 16 characters. When interfacing with an LCD screen only, it doesn't matter the communication mode. When incorporating other modules and shields, we require other port pins for various usage. There I will be demonstrating the 4-bit mode. In this article, I will be demonstrating two operations :

  1. Static 2 line message display
  2. Scrolling 2 line message display
The circuit will be the same for all modes and there will be minor changes in the code. I will be adding the Scrolling Text mode in the LCD screen in the coming days.


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STATIC MESSAGE DISPLAY ON 16x2 LCD SCREEN

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Code : Embedded C
IDE : Keil uVision 5
Simulator : Proteus 8 Professional
uController : AT89C51


/* Created  by mbedsyst */

#include<reg51.h>
sbit rs = P1^0;
sbit rw = P1^1;
sbit en = P1^2;
void lcdcmd (unsigned char);
void lcddat (unsigned char);
void lcdinit ();
void delay( unsigned int count)
{
 unsigned int i;
 while(count)
 {
 i = 115;
 while(i>0)
 {
 i--;
 }
 count--;
 }
}
void lcdinit ()
{
 lcdcmd (0x38); // 5X7 matrix crystal
 delay(100);
        lcdcmd (0x01); // clear screen
 delay(100);
 lcdcmd (0x10); // cursor blinking
 delay(100);
 lcdcmd (0x0C); // display on
 delay(100);
 lcdcmd (0x80); // Force cursor to 1x1 position
 delay(100);
}
void lcdcmd (unsigned char val)
{
 P2 = val;
 rs = 0;
 rw = 0;
 en = 1;
 delay(10);
 en = 0;
}
void lcddat (unsigned char val)
{
 P2 = val;
 rs = 1;
        rw = 0;
 en = 1;
 delay(10);
 en = 0;
}
lcd_dataa (unsigned char *disp)    // function to send string to LCD
{
 int x;
 for(x=0;disp[x]!=0;x++)
 {
 lcddat (disp[x]);
 }
}
void main()
{
 P2 = 0x00; // output declaration, data lines d0-d7 connect
 lcdinit();
 while (1)
 {
lcdcmd (0x80);
 lcd_dataa (" System  Online");
 delay(2500);
 lcdcmd (0xC0);
 lcd_dataa ("    mbedsyst");
 delay(2500);
        }
}

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