Thread: problems with portwrite functions

  1. #1
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    Oct 2001
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    14

    problems with portwrite functions

    i need to write a 3 byte protocol to it with the first byte containing 255 the second 1 and the third 127. but in my port write function it gives me an error function does not take 3 parameters
    my code so far is

    /************************************************** *********************

    PortWrite (BYTE Byte)

    ************************************************** *********************/
    void PortWrite (BYTE Byte)
    {
    DWORD dwError,
    dwNumBytesWritten;

    if (!WriteFile (hPort, // Port handle
    &Byte, // Pointer to the data to write
    1, // Number of bytes to write
    &dwNumBytesWritten, // Pointer to the number of bytes
    // written
    NULL)) // Must be NULL for Windows CE
    {
    // WriteFile failed. Report error.
    dwError = GetLastError ();
    }
    }

    how can i write this three byte protocol to the serial port?? iam using a windows OS and using embedded C++
    hope u can help thanx

  2. #2
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    Oct 2001
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    14

    sorry

    no i didnt ignore your suggestions i just couldnt get them to work!
    could i email u my code so you could have a look at it??

  3. #3
    and the hat of int overfl Salem's Avatar
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    > could i email u my code so you could have a look at it??
    No.

    Code:
    unsigned char buff[] = { 255, 1, 127 };
    if (!WriteFile (hPort,              // Port handle
                    buff,               // Pointer to the data to write 
                    3,                  // Number of bytes to write
                    &dwNumBytesWritten, // Pointer to the number of bytes written
                    NULL))              // Must be NULL for Windows CE
    {
        // WriteFile failed. Report error.
        dwError = GetLastError ();
    }
    Did you try this?
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.

  4. #4
    Registered User
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    yep tried it

    i tried that but i have got probs in my main what should i have in there other than
    /*
    *
    * controller.cpp
    *
    *
    *
    *
    */

    #include <windows.h>
    #include "carcontrol.h"


    /************************************************** *********************

    WINMAIN ( HINSTANCE hInstance,
    HINSTANCE hPrevInstance,
    LPTSTR lpCmdLine,
    int nCmdShow)

    ************************************************** *********************/

    int WINAPI WinMain( HINSTANCE hInstance,
    HINSTANCE hPrevInstance,
    LPTSTR lpCmdLine,
    int nCmdShow)


    {

    DWORD dwError;
    hPort = INVALID_HANDLE_VALUE; // Serial port handle
    hReadThread = NULL; // Handle to the read thread



    lpszDevName = TEXT("COM1:");

    // Initialize the port.
    if (!PortInitialize (lpszDevName))
    {
    return 0 ;
    }



    PortClose(hPort) ;


    return 0 ;

    }


    because at the moment nothing is been sent to the serial port

    ps thanks for your help

  5. #5
    and the hat of int overfl Salem's Avatar
    Join Date
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    > because at the moment nothing is been sent to the serial port
    Well your main only seems to open and close the port

    Perhaps you should attach more code - this board supports attachments.
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.

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