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#63574 Help on Netduino 2 Serial Communication to PC

Posted by yxhu on 18 July 2015 - 02:58 PM in Netduino 2 (and Netduino 1)

Hi Chris,
 
I am new to this forums and this is my first post. Recently I have purchased a few ND2s. I setup a very small serial communication program and unfortunatey it didn't work as expected. Here is the setting:
 
On netduino, I am using COM4, the connection to the PC as:
 
ND            ----->  PC
 
SDA(RX)   ----     TX
SCL (TX)   ----     RX
 
 
Program runs on the ND:
 

private static SerialPort _serialPort;

public static void Main()
{
   _serialPort = new SerialPort("COM4", 9600, Parity.None, 8, StopBits.One);
   _serialPort.Open();

    System.Text.UTF8Encoding encoder = new System.Text.UTF8Encoding();
    byte[] bytesToSend  = encoder.GetBytes("abc");

    while(true){
       _serialPort.Write(bytesToSend, 0, bytesToSend.Length);
    }
}

 
 
Program runs on the PC:
 

public Program()
{
    _serialPort = new SerialPort();
    _serialPort.PortName     = "COM3";
    _serialPort.BaudRate     = 9600;
    _serialPort.DataBits     = 8;
    _serialPort.DiscardNull  = true;
    _serialPort.StopBits     = StopBits.One;
    _serialPort.Parity       = Parity.None;
    _serialPort.DataReceived += _serialPort_DataReceived;
    _serialPort.Open();
}

private void _serialPort_DataReceived(object sender, SerialDataReceivedEventArgs e)
{
     var _buffer = new byte[_serialPort.BytesToRead];
      _serialPort.Read(_buffer, 0, _buffer.Length);

     Console.WriteLine(System.Text.ASCIIEncoding.UTF8.GetString(_buffer));
}

  
Basically, I wanted to let ND to keep sending string "abc" to the PC. After I have tried different Baud rates, i.e.  9600, 4800, 2400. I am always getting very wired result at PC end, please see the attached screenshot.

 

I suspect there might be the Baud rate mismatch. However, I have tripple checked my code, both sides have identical settings on the serial port.

 

I spent many hours googling with no luck.

 

 

On other weird thing was, I needed to set 'DiscardNull = true' on the PC end, otherwise I am getting massive '0x00' bytes from ND.

 

I am using VS2010, Micro Framework 4.2, Netdunio SDK 4.2.2.2. I started with VS2013, Micro Framework 4.3, and Netduino SDK 4.3.2.1, unforturnately I couldn't debug the program on ND. I always get error  "The debuging target is not in an initialized state; rebooting......", So I have reverted everything back to VS2010, then I could debug the program.

 

I have also attached the output from "Device capabilities" in the MSDeploy FYI.

 

 

 

 

 

 

 

 

Attached Thumbnails

  • output.png

Attached Files




#63640 Help on Netduino 2 Serial Communication to PC

Posted by yxhu on 24 July 2015 - 06:28 AM in Netduino 2 (and Netduino 1)

Hi Chris,

 

Thank you so much for shedding the light on this one....  I have resolved issue by replacing the MAX232 as it was malfunction. Usually MAX232 quite stable didn't know why for this instance it stopped work. Maybe I am just too new to this Netduino world and got bully by this small piece of chip. :D

 

yx




#63654 Downgrade from 4.3.1 to 4.2.2.2

Posted by yxhu on 25 July 2015 - 06:13 AM in Netduino 2 (and Netduino 1)

Hi Chris,
 
I have upgraded my ND2 to v4.3.1, unfortunately it didn't work well with VS2013. Basically I can't attach debugger to it after successful deploy via VS2013. I decided to downgraded. I have followed per instruction as described here:
 
 
Everything seems OK to me, however when I reattach the ND2 back to the PC, MFDeploy.exe was no longer able to detect it anymore.
If I flashed it back to 4.3.1, everything started to work again.
 
 
Any advises?
 
yx
 




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