def get_channel(self, ch_num):
        """Get channel state (specified with ch_num), return 0=disabled or 1=enabled."""
        if ch_num < 0 or ch_num > self.PORTS_COUNT - 1:
            return None
        register = self.get_control_register()
        if register is None:
            return None
        value = ((register >> ch_num) & 1)
        return value