EMX Dev-Board Com-2 | Optical-probe issue

NETMF & Gadgeteer
1

Hi, I want to run a optical probe in the com-2 port off my emx-dev-board.

Thats the optical probe:
http://opticalprobe.net/en/iec_probes.html#BSC1111

The problem is, when I plug the probe in the rs232 (com-2) port of the dev-board nothing happends, no power, nothing.

The probe should work with 3.3V so it should work. It is passively powered by the DTR and/or RTS signal.

Hope any one can help me.

Best regards

2

Did you try to instantiate SerialPort in the code?

3

The RS232 connector on EMX dev board does not support pin 4 DTR.

There might be an issue with the power driving capabilities of the RTS pin.

4

My Code is following:

using System.IO;
    using System.IO.Ports;
    using GHIElectronics.NETMF.Hardware;
    using GHIElectronics.NETMF.IO;
    using Microsoft.SPOT;
    using Microsoft.SPOT.Hardware;

    public class Program
    {
        internal const int bufferSize = 256;
        internal static PersistentStorage storage;
        internal static FileStream writerFile;
        internal static byte[] buffer = new byte[bufferSize];
        internal static SerialPort com2 = new SerialPort("COM2");
        internal static string data = string.Empty;

        public static void Main()
        {
            if (PersistentStorage.DetectSDCard())
            {
                storage = new PersistentStorage("SD");

                InputPort button = new InputPort(EMX.Pin.IO30, false, Port.ResistorMode.PullUp);

                storage.MountFileSystem();

                writerFile = new FileStream("\\SD\\powerLog.txt", FileMode.Append);

                com2.DataReceived += new SerialDataReceivedEventHandler(com2_DataReceived);
                com2.ErrorReceived += new SerialErrorReceivedEventHandler(com2_ErrorReceived);

                com2.Open();

                byte[] test = System.Text.UTF8Encoding.UTF8.GetBytes("/?!\r\n");
                com2.Write(test, 0, test.Length);
                com2.Flush();

                while (button.Read() == true)
                {
                }

                com2.Close();

                writerFile.Flush();

                storage.UnmountFileSystem();
            }
        }

        static void com2_ErrorReceived(object sender, SerialErrorReceivedEventArgs e)
        {
            Debug.Print("Error");
        }

        static void com2_DataReceived(object sender, SerialDataReceivedEventArgs e)
        {
            Debug.Print("Data");

            int byteRead = 0;

            byteRead = com2.Read(buffer, 0, bufferSize);
            writerFile.Write(buffer, 0, byteRead);
        }
    }

Like Mike says the pin 4 is always low, thats my problem. Is there a workaround, or whats the problem?

Best regards

5

I am not sure if it was fixed in MF 4.2, but with 4.1 you have to register for serial port events after you have opened the port.

6

Ok, but this doesn’t change the fact that pin 4 (DTR) is all the time low. Is there a way to geht it manualy high? Is it connected, the schematic confuses me a bit, pin 4 (DTR) looks like a input pin and not outgoing.

Best regards

7

According to the schematic for V1.3 of the EMS development system, pin 4 of the X1, the RS232 connector , is not connected to anything.

You could solder a jumper wire between pin 4 and and the 3.3v

8

Mike, thanks, your solution worked!

Best regards