#include

#define uchar unsigned char

uchar times;

sbit p10=P1^0;

sbit p11=P1^1;

void t0isr() interrupt 1

{

TH0=(65536-25000)/256;

TL0=(65536-25000)%256;

p10=~p10;

times++;

if(times>=4)

{

times=0;

p11=~p11;

}

}

main()

{

TMOD=0x01;

TH0=(65536-25000)/256;

TL0=(65536-25000)%256;

TR0=1;

ET0=1;

EA=1;

while(1);

}