door censor using 8051

Posted on 26 August 2014 at 02:21

code

#include <at89x51.h>
sbit lights= P3^1;
sbit full= P3^0;
/*=============================================================================
=============================================================================*/
unsigned char ex0_isr_counter = 0;
unsigned char enter=0;
unsigned char leave=0;

void display()
{
   unsigned char a,b,c;
   a=ex0_isr_counter%10;
   b=ex0_isr_counter/10;
   b=b<<4;
   c=b|a;
   P2=c;
}
void ex0_isr (void) interrupt 0
{
   leave=1;
   if (enter==1)
   {
       ex0_isr_counter++;
       leave=0;

   }
   enter=0;
}

void ex1_isr (void) interrupt 2
{
   enter=1;
   if (leave==1)
   {
       ex0_isr_counter--;
       enter=0;

   }
   leave=0;
}

void main (void)
{
   P2 = 0x00;
   IT0 = 1;
   IT1 = 1;
   EX0 = 1;
   EX1 = 1;
   EA = 1;
   while (1)
   {
       if (ex0_isr_counter==0)
           lights=0;
       else
           lights=1;
       if (ex0_isr_counter>19)
           full=1;
       else
           full=0;


       display();
   }
}