sfr P0 = 0x80;
main()

{
int i,j,count,delay;
count=20,delay=2000;

while(1)
{
for (j=0;j<count;j++)
  {
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++);
  }
//////////////////////////////////////////////

for (j=0;j<count;j++)
  {
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++);
  }
}

}