SIGNAL (SIG_PCINT)
{
	int pbm = PINB;

	if (pbm & (0<<PINB1)) {
		while (PINB & (0<<PINB1));
		a();
		// initialize
	}
	if (pbm & (0<<PINB0)) {
		while (PINB & (0<<PINB0));
		b();
		// send out codes
	}

}