#include <8051.h>


#define DELAY_TIME 10000

void Delay(void) {
  volatile unsigned short int i;

  i = DELAY_TIME;  

  while (i > 0) {
    i--;
  }
}


void main(void) {

  while(1) {
    P3 = 0xAA;
    Delay();
    P3 = 0x55;
    Delay();
  }
}