Serial port чтение данных через thread

 public class Atmega : IDisposable
    {
        SerialPort port;
        Thread _th_recived;
        byte rxin=0,tx_send=0;
        string pp;
        byte[] rx_buff = new byte[10];
        byte[] buff2 = new byte[6];
        public Atmega ()
        {
          serial_set();
            _th_recived = new Thread(rx);
        }
        public void serial_set()
        {
            string[] ports = SerialPort.GetPortNames();
            foreach (string port in ports)
            {  pp = ports[0];  }
       
            port = new SerialPort(pp);
            port.BaudRate = 9600;
            port.DataBits = 8;
            port.ReadTimeout = 0;
        }
        public void Open()
        {
            port.Open();
        }
        public void Start()
        {
            Open();
            txsend();
            _th_recived.Start();
        }
        
        void rx(object state)
        {
            port.Read(rx_buff, 0, 1);
            rxin = rx_buff[0];  
        }
        public byte rxx()
        {
            return rxin;
        }
        void txsend()
        {   buff2[0]= 5;
            port.Write(buff2,0,1);
            tx_send = 1;
        }
        public byte txx()
        {
            return tx_send;
        }

        public void Dispose()
        {
            if(_th_recived != null)
        {
                _th_recived.Abort();
                _th_recived = null;
            }
            if (port != null)
            {
                if (port.IsOpen)
                    port.Close();
                port = null;
            }
        }

    }

private void timer1_Tick(object sender, EventArgs e)
        {
            if (opencomss == 1)
            {
                Atmega avr = new Atmega();
                avr.Start();
                rx_byte =avr.rxx();//Вот здесь не записывается данные на  rx_byte
                richTextBox1.Text = Convert.ToString(rx_byte);
                avr.Dispose();
            }
            
        }