#include <reg51.h>

sbit D3 = P1^0;
sbit D2 = P1^1;
sbit D1 = P1^2;
sbit D0 = P1^3;
sbit VT = P1^4;

void deasil(int delay)
  {
   int i;
   P0=0xfe;    
   for(i=0;i<delay;i++);
   P0=0xfd;
   for(i=0;i<delay;i++);
   P0=0xfb;
   for(i=0;i<delay;i++);
   P0=0xf7;
   for(i=0;i<delay;i++);
  }

widdershins(int delay)
  {
   int i;
   P0=0xf7;
   for(i=0;i<delay;i++);
   P0=0xfb;
   for(i=0;i<delay;i++);
   P0=0xfd;
   for(i=0;i<delay;i++);
   P0=0xfe;
   for(i=0;i<delay;i++);
  }


main()

{
  while(1)
    {
      if (D3==1) deasil(2000);
	  if (D2==1) widdershins(2000);
	  if (D1==1) deasil(5000);
	  if (D0==1) widdershins(5000);
    }
}