Simple ELEVATOR program for 8051

#include<reg51.h>
#include"lcd_display.h"

sbit ON = P1^0;
sbit floor1 = P1^1;
sbit floor2 = P1^2;
sbit floor3 = P1^3;
sbit dooropen = P1^4;

sbit motorF = P2^0;
sbit motorR = P2^1;
sbit motor_en = P2^3;
sbit led_doorOpen = P2^2;
sbit ON_led = P2^4;

void delay_sec(int);

short int PresentLevel = 0, RequestLevel;


void main()
{
motorF = motorR = led_doorOpen = motor_en = ON_led = rs = en = 0;
ON = floor1 = floor2 = floor3 = dooropen = 1;



TMOD = 0x01;
P3=0x00;
lcd_init();
motor_en=0;

while(1)
  {
    while(!ON)
     {
     ON_led=1;
     lcd_cmd(0x01);
     lcd_dataS("welcome");
     lcd_cmd(0xc0);
     lcd_dataS("present floor-");
     lcd_dataint(PresentLevel);

     while(floor1==1 && floor2==1 && floor3==1 && dooropen==1);
      //wait till any option is pressed
 
  if(dooropen==0)  // if door is opened
  {
     while(floor1==1 && floor2==1 && floor3==1);
      //wait for user option(now you are in the lift)
    if(floor1==0)  
    RequestLevel=1;  //used to store the respective option
      if(floor2==0)
       RequestLevel=2;
      if(floor3==0)
      RequestLevel=3;
   }  

   if(floor1==0)     //this is when pressing outside the lift
   RequestLevel=1;
   if(floor2==0)
   RequestLevel=2;
   if(floor3==0)
   RequestLevel=3;

   lcd_cmd(0x01);
   lcd_dataS("Requested f");
   lcd_dataint(RequestLevel);

   while(PresentLevel &lt; RequestLevel)
   {
    motor_en=1;   //if presentlevel is less than requestlevel
    motorF=1;      // turn motor in forward direction
    motorR=0;
    delay_sec(5);
    lcd_cmd(0xc0);
    PresentLevel++;
    lcd_dataS("PresentLevel-");
    lcd_dataint(PresentLevel);
   }
   motor_en=0;
   while(PresentLevel &gt; RequestLevel)
   {
    motor_en=1;    //if presentlevel is greater then requestL
    motorF=0;       //turn motor in REVERSE direction
    motorR=1;
    delay_sec(5);
    PresentLevel--;
    lcd_cmd(0xc0);
    lcd_dataS("PresentLevel-");
    lcd_dataint(PresentLevel);
   }
   motor_en=0;

   if(PresentLevel==RequestLevel)
   {
    led_doorOpen=1;
    lcd_cmd(0x01);
    lcd_dataS("level reached");
    lcd_cmd(0xc0);
    lcd_dataS("door opened ");
    delay_sec(10);
    led_doorOpen=0;
   }
   }
   ON_led=0;
  }
}

void delay_sec(int x)
{
int i = 0,j;

for(i = 0;i
{
  for(j = 0;j&lt;14;j++)
  {
    TR0 = 1;
 while(TF0 != 1);
 TF0 = 0;
 TR0 = 0;
  }
}
}