C# Visual Studio console serial interface

Question

I am starting from the ground up and trying to write a simple console to interface with a serial port on a windows 7 computer.

I am using:

• Visual Studio 2010 Ultimate
• C# console project
• Code: http://pastebin.com/0ADaEiSY

Code:

 using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Text;

 using System.IO.Ports;

 namespace ConsoleApplication1
 {
    class Program
    {
        public static void Main()
        {
            SerialPort mySerialPort = new SerialPort("COM5");


        mySerialPort.BaudRate = 9600;
        mySerialPort.Parity = Parity.None;
        mySerialPort.StopBits = StopBits.One;
        mySerialPort.DataBits = 8;
        mySerialPort.Handshake = Handshake.None;

        mySerialPort.DataReceived += new SerialDataReceivedEventHandler(DataReceivedHandler);

        mySerialPort.Open();

        mySerialPort.Write("This is a test");

        Console.WriteLine("Press any key to continue...");
        Console.WriteLine();
        Console.ReadKey();
        mySerialPort.Close();
    }

    private static void DataReceivedHandler(
                        object sender,
                        SerialDataReceivedEventArgs e)
    {
        SerialPort sp = (SerialPort)sender;
        string indata = sp.ReadExisting();
        Console.Write(indata);
    }
  }
}

So far i have ran this code and interfaced with a xbee module connected to my computer. That xbee module sent the serial data to another xbee connected to a msp430. The msp430 is programmed to take whatever it receives and echo it back. This works with the code I have. In my console I will get "This is a test" echoed back onto the console window.

The problem I am having is when I use a virtual serial connection to a putty window. I am using this to try to ease development and not have to use hardware all of the time. I will use HHD Free Virtual Serial Ports to create a bridged connection between two serial ports. I will connect one to the putty terminal and the other will be for my console program. When running the program I recieve the error.

"A first chance exception of type 'System.TimeoutException' occurred in System.dll"

on the line

mySerialPort.Write("This is a test");

But the "This is a test" will appear on the Putty terminal. If I remove the "mySerialPort.Write("This is a test");" line and attempt to send data from the Putty window to the console window, nothing appears.

Again this works with my hardware solution just fine.

Please help and i will try to clarify any questions. Thank you again.

Answer 1

I guess the problem is in virtual utility you are using. It seems it sets pin states incorrect. If I use 2 putty instances and connect to bridged ports I see infinite sending of symbol I entered. So I think your code is fine.

When I was working on such tasks I used a special cable for connecting 2 hardware com ports (com1 and com2, if you don't have them you can try usb-to-com converters) and it worked fine.

Answer 2

I'm has the very same problem with HHD Free Virtual Serial Ports, but this work great with asynchronous write operation.

Also you can replace

mySerialPort.Write("This is a test");

with (for example)

var buffer = Encoding.ASCII.GetBytes("This is a test");
mySerialPort.BaseStream.BeginWrite(buffer, 0, buffer.Length, ar => mySerialPort.BaseStream.EndWrite(ar), new object());