#include<reg52.h>
#include<absacc.h>

#define unit unsigned int
#define uchar unsigned char

sbit L0=P1^0;
sbit L1=P1^1;
sbit L2=P1^2;
sbit L3=P1^3;
uchar data BUFFER[1]={0};

void main()
{
	P1=0xff;
	EA=1;
	ET0=1;
	IT1=1;
	TMOD=0x01;
	TH0=60536/256;
	TL0=60536%256;
	TR0=1;
	for(;;);
}

void timer0(void) interrupt 1 using 1
{
	TH0=60536/256;
	TL0=60536%256;
	BUFFER[0]=BUFFER[0]+1;
	if(BUFFER[0]==100)
	{
		L3=!L3;
		L2=!L2;
		L1=!L1;
		L0=!L0;
	}
}