pvanroos

Hi all,

Did anyone ever figure this out?  I've got a RS-485 Shield from LinkSprite and I can't get it work.  Here are some details from my project:

1. Linksprite RS-485 Shield V2.1 - http://linksprite.co...2.1_for_Arduino

2. Using SerialPort for communication:  http://msdn.microsof...y/ee432679.aspx

3. Communicating over CAT6 twisted pair to a device at other end expecting 9600 baud, Even parity, 7 character bits, and one stop bit.

4. Twisted pair inserted into H2 485-A and 485-B ports.

5. Netduino Plus 2 (bought a month ago with no firmware updates)

6. Set to 5V using jumper.

7. Set to D0 and D1 using jumper.

8. Set to TX_CTRL using jumper.

9. Plugged into computer to deploy code.  Headers are not soldered but they fairly snug and not loose.

10: Code:

        static SerialPort serial;
        static OutputPort led;
        const int bufferMax = 10000;
        static byte[] buffer = new byte[bufferMax];
        static int bufferLength = 0;

        public static void Main()
        {         
            led = new OutputPort(Pins.ONBOARD_LED, false);
            serial = new SerialPort(SerialPorts.COM1, 9600, Parity.Even, 7, StopBits.One);
            serial.ReadTimeout = 1000;      
            serial.DataReceived += serial_DataReceived;
            serial.ErrorReceived += serial_ErrorReceived;
            serial.Open();

            while (true)
            {
                {
                    led.Write(true);
                   
                    Debug.Print("Request sent");
                    string hexrequest = "2F3F3030303330303030313039363030210D0A";
                
                    // Create request
                    byte[] seq = StringToByteArray(hexrequest);

                    if (serial.CanWrite)
                        serial.Write(seq, 0, seq.Length);    
                                           
                    led.Write(false);
                }

                string line = "> ";

                for (int i = 0; i < bufferLength; i++)
                {
                    line += buffer[i] + ",";
                }

                Debug.Print(line);
                if(serial.IsOpen) Debug.Print("Port is open.");
                Thread.Sleep(10000);
            }
        }
        static void serial_ErrorReceived(object sender, SerialErrorReceivedEventArgs e)
        {
            if (e.EventType == SerialError.TXFull)
            {
                Debug.Print("Error:  TXFull");
            }
            else if (e.EventType == SerialError.RXParity)
            {
                Debug.Print("Error:  RXParity");
            }
            else
            {
                Debug.Print("Error:  Some other error");
            }
        }

        static void serial_DataReceived(object sender, SerialDataReceivedEventArgs e)
        {

            Debug.Print(dataRecLineNumber + ": Data received ******* - " + t );
       
            int bytesReceived = serial.Read(buffer, bufferLength, bufferMax - bufferLength);
            if (bytesReceived > 0)
            {
                bufferLength += bytesReceived;
                if (bufferLength >= bufferMax)
                    throw new ApplicationException("Buffer Overflow.  Send shorter lines or increase lineBufferMax.");
            }
        }

@CW2:  Could the same problem happen with RS-485 communication over a CAT6 twisted pair?  i.e. too low voltages 3.3 to 5V versus 10 to 15?