Hi
I'm writing a program in MatLab. The idea is to call a C# class library (dll) that connects to a serial interface, gets some specified data and sends it back to the matlab program.
When matlab calls the dll, it passes a callback function handle to it. When the
SerialDataReceivedEventHandler pops up with
the requested data, the matlab callback should be called from the dll...
The following code works for a C# program calling the dll function, but with Matlab I get an:
"Unhandled .NET exception: Asynchronous delegate invocation
is not supported."
What exactly does this error mean:
- Is my idea to have a dll generate an event for Matlab
simply not possible?
- Is there a mistake in my code?
- Am I choosing the wrong approach, is tehre a better way?
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The ComInterface.dll code:
using System;
using System.IO.Ports;
namespace ComInterface
{
// Prototype for MatLab callback function
public delegate void AnswerEvent(object sender, string msg);
public class RS232
{
static SerialPort port;
public static AnswerEvent matlabCallback;
// Function to setup and open the serial port
public static SerialPort Open(string portName)
{
// Specify port settings
port = new SerialPort(portName);
port.BaudRate = 115200;
port.Parity = Parity.Odd;
port.StopBits = StopBits.One;
port.Handshake = Handshake.None;
port.ReadTimeout = 10;
port.WriteTimeout = 10;
// Open serial port
if (! port.IsOpen)
{
port.Open();
}
// Clear runt buffer data
port.DiscardInBuffer();
port.DiscardOutBuffer();
// Register serial port callback function
port.DataReceived += new SerialDataReceivedEventHandler(port_DataReceived);
// Just for debugging
return port;
}
// Function to read data from external device
public static int ReadRegister(int addr, AnswerEvent fnc)
{
// Store Matlab callback function (could this be done differently?)
matlabCallback = fnc;
// Device stecific message protocol:
// 1. Byte = Status (0x00 = Read)
// 2. Byte = Address
// 3.-6. Byte = 4 Byte Data
byte[] sendMsg = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
sendMsg[1] = Convert.ToByte(addr);
// Send read request to device
port.Write(sendMsg, 0, 6);
// Just for debugging
return 1;
}
// Callback function from serial port
public static void port_DataReceived(object sender, SerialDataReceivedEventArgs e)
{
byte[] rcvMsg = new byte[6];
// Read answer from external deice
port.Read(rcvMsg, 0, 6);
// Call event handler function in Matlab
// => This leads to System error (Matlab crashes): ".NET unhandled exception: Asynchronous delegate invocation is not supported."
matlabCallback(port, BitConverter.ToString(rcvMsg));
// What happens here? Does program go to matlab and never come back? Is there another way to generate an event?
// Better Question: Is MatLab still waiting to be called back???
}
}
}
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The Matlab program that calls the ComInterface.dll:
% MatLab function:
function GetRegister()
global done
done = 0;
NET.addAssembly('C:\ComInterface.dll');
% Open serial port on COM1 Interface
ComInterface.RS232.Open('COM1');
% Read register 23 and call my_callback_fcn when done.
ComInterface.RS232.ReadRegister(23, @my_callback_fcn);
while done == 0
% Make sure MatLab program is still running when my_callback_fcn is
% called from ComInterface.dll
end
end
% Callback function, called from ComInterface.dll
function my_callback_fcn(obj, string_arg)
global done
done = 1;
% Print register content to MatLab console
disp(string_arg)
end
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System Components:
- MatLab 7.11.0 2010b
- Visual Studio 10
- .NET Framework 4
Thanks for any suggestions in advance.
Simon
