#include<8051.h>

void delay(unsigned int i)

{

while(i!=0)

{

i–;

}

}

void main()

{

while(1)

{

P0_0=1,P0_1=0,P0_2=0,P0_3=0;

delay(10000);

P0_0=0,P0_1=1,P0_2=0,P0_3=0;

delay(10000);

P0_0=0,P0_1=0,P0_2=1,P0_3=0;

delay(10000);

P0_0=0,P0_1=0,P0_2=0,P0_3=1;

delay(10000);

}

}