#includesbit pluse=P1^0;void t0isr() interrupt 1{TH0=(65536-50000)/256;TL0=(65536-50000)%256;pluse=~pluse;}main(){TMOD=0x01;TH0=(65536-50000)/256;TL0=(65536-50000)%256;TR0=1;ET0=1;EA=1;while(1);}