FINAL.c

#include<reg51.h>	
#include<string.h>
#include<stdio.h>

unsigned char str1[10]="RPM= ";
unsigned char str2[5];
unsigned char temp[10];
unsigned char cmd[5]={0x38,0x0E,0x06,0x01,0x80};
unsigned char i;

sbit E=P0^0;   	 //enable pin
sbit RW=P0^1;  	 //read/write pin
sbit RS=P0^2;	 //register select pin
sbit busy= P1^7; //busy pin

typedef unsigned int uint;

uint count = -1,rpm=0;

void delay(uint x)
{
	int i;
	for(i=0;i<x;i++) 
	{
    	TMOD = 0x01;          // Timer 0 Mode 1
    	TH0= 0xFC;     		  //initial value for 1ms
    	TL0 = 0x66;
    	TR0 = 1;     		  // timer start
    	while (TF0 == 0); 	  // check overflow condition
    	TR0 = 0;    		  // Stop Timer
    	TF0 = 0;   			  // Clear flag
  	}
}


void lcdready()//to prepare LCD and get it ready
{
	busy=1; // to set as input line
	RS=0;
	RW=1;
	while(busy==1)
		{
			//reading pin
			E=0;
			delay(1);
			E=1;
		}
}// end of lcdready

void cmdwrt(unsigned char cmdval)//to send command instruction to LCD
{
	lcdready();
	P1=cmdval;
	RS=0;	//to write command in command register
	RW=0;
	E=1;	//enable=1, to enable LCD and take data from data lines
	delay(1);
	E=0;
}// end of cmdwrt


void lcddata(unsigned char dataval)// to send display data to LCD
{
	lcdready();
	P1=dataval;
	RS=1;
	RW=0;
	E=1;
	delay(1);
	E=0;
}// end of lcddata


void int_to_str(unsigned char str[],unsigned int x)// to convert rpm value from int to string
{
    int i, rem, len = 0, n;
 
    n = x;
    while (n != 0)
    {
        len++;
        n /= 10;
    }
    for (i = 0; i < len; i++)
    {
        rem = x % 10;
        x = x / 10;
        str[len - (i + 1)] = rem + '0';
    }
    str[len] = '\0';
		
}// end of int_to_str 



void Int_Init()				
{
			
	IT0 = 1;	         // set detection to falling edge (sets external interrupt event type onto int0 pin)
	EX0 = 1;      	    // Enable external interupt or int0 or p3.2 pin	
	EA  = 1;	       //Enable global interrupt
}
											
void ex0_ISR(void) interrupt 0    	   // interrupt service routine
{ 
	count++;
	
	//delay(500);
		
}
 
void lcdinit() // to initialise the LCD
{
	unsigned char x;
	for(x=0;x<5;x++)
		cmdwrt(cmd[x]);		   
}


void main()
{
    Int_Init();// external interrupt initialize function
	lcdinit();
	
  while(1)         
	{
		rpm=0;
		count=0;
		delay(1000);
		lcdinit();
		cmdwrt(0x01);// to clear the screen

		rpm = count*60;

		int_to_str(str2,rpm); // convert int to string
		strcpy(temp,str1);
		strcat(temp,str2);	  // concatenate the rpm value string to original string
		for(i=0;i<strlen(temp);i++)	 // sending data to function to display on LCD
			lcddata(temp[i]);				   
	}
}