CODEWITHSUNDEEP
c#windowstimer
Abhishek Kumar
Abhishek Kumar

Reputation: 35

Obtaining Millisecond Resolution (cycle Time) in Windows Embedded Application

I am making an Application in C# which reads CAN (Control Area Network) messages and sends them too. I need to do it in 10 milliseconds. The OS i am using is Windows Embedded 7 Pro. 

    public void ID0008Update10ms(DataTable supportPoints, int a)
    { 
        System.TimeSpan timer10ms = System.TimeSpan.FromMilliseconds(10); 
        intialiseCAN();
        while (a==1)
        {
            Stopwatch t = Stopwatch.StartNew();
            sendCAN();
            getCAN();
            ID0006NavComStatus(supportPoints);
            string state = Convert.ToString(gNavStatus);


            while (t.Elapsed < timer10ms) 
            { /*nothing*/}
        }

    }

The issue is the sendCAN() and reciveCAN() dynamically load the .dll file

    public int sendCAN(ref can_msg msg, IntPtr pDll)
    {
        if (pDll == IntPtr.Zero)
        {
            MessageBox.Show("Loading Failed");
        }
        IntPtr pAddressOfFunctionToCall = NativeMethods.GetProcAddress(pDll, "CAN_Transmission");
        CAN_Transmission sendCAN = (CAN_Transmission)Marshal.GetDelegateForFunctionPointer(pAddressOfFunctionToCall, typeof(CAN_Transmission));

        int result = sendCAN( ref msg);
        return result;
    }

This makes the cycle slow, I am not able to send the Message within 10ms. Can anyone propose a better way. Please remember. I use Windows Embedded.

Upvotes: 0

Views: 69

Answers (1)

James
James

Reputation: 9975

You should move as much as possible outside the loop. If it doesn't absolutely have to be there, move it. Along the lines of....

private CAN_TransmissionMethod CAN_Transmission;

//Cache the delegate outside the loop.
private bool InitialiseCAN2(IntPtr pDll)
{
    if (pDll == IntPtr.Zero)
    {
        Log("Loading Failed");
        return false;
    }
    IntPtr pAddressOfFunctionToCall = NativeMethods.GetProcAddress(pDll, "CAN_Transmission");
    CAN_Transmission = (CAN_TransmissionMethod)Marshal.GetDelegateForFunctionPointer(pAddressOfFunctionToCall, typeof(CAN_Transmission));
    return true;     
}

public int sendCAN(ref can_msg msg)
{
    if (CAN_Transmission == null)
        return -1;//Can't send, no delegate, Log, Fail, Explode... make a cup of tea.
    int result = CAN_Transmission( ref msg);
    return result;
}

public void ID0008Update10ms(DataTable supportPoints, int a)
{ 
    System.TimeSpan timer10ms = System.TimeSpan.FromMilliseconds(10); 
    intialiseCAN();
    initialiseCAN2(pDll)
    while (a==1)
    {
        Stopwatch t = Stopwatch.StartNew();
        sendCAN(ref thereIsSupposedToBeAMessageHere);
        getCAN(ref probablySupposedToBeSomethingHereToo);
        ID0006NavComStatus(supportPoints);
        string state = Convert.ToString(gNavStatus);


        while (t.Elapsed < timer10ms) 
        { /*nothing*/}
    }

}

Upvotes: 1

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