Sending Byte to serial port

Quote:

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Originally Posted by Bfrancesco

OK thank you. I didn't find http://msdn.microsoft.com/en-us/libr...(v=vs.80).aspx.
Why the compiler gives the follow error:
- syntax error: ';' before identifier ''^" ?

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Because you are using the wrong symbol "ˆ" instead of the "^"

Quote:

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Originally Posted by Bfrancesco

One fast question...
I'm implementing a 16bit CCITT CRC algorithm and I have found this sample:

Code:

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unsigned int crc(unsigned char data)
        {
                static unsigned int crc;
               
                crc = (unsigned char)(crc >> 8) | (crc << 8);
                crc = data;
                crc ˆ= (unsigned char)(crc & 0xff) >> 4;

                crc ˆ= (crc << 8) << 4;
                crc ˆ= ((crc & 0xff) << 4) << 1;
               
                return crc;
                }

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I'd like to understand how work the "^=" operator.

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Because what looks like '^' in the code actually isn't ^ but some other symbol. Replace what looks like '^' with an actual ^ and it should then compile.

Yes, Thank you!

Hi

Now I have obtained the correct packet byte to send after coding and CRC calculation. This is: "01 02 04 01 02 09 0c 10 02 06 12 01 01 13 01 01 49 f1 00"
Now I want to send it using the project in http://www.naughter.com/serialport.html. But i need to understand well the code of this project to send correctly. It is composed mainly by 2 files: app.ccp and SerialPort.cpp. In the SerialPort.cpp file there is the function:

Code:

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void CSerialPort::Write(const void* lpBuf, DWORD dwCount, OVERLAPPED& overlapped, DWORD* pBytesWritten)

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and I think that it's the function that i must use to send the packet. In the app.ccp this function is called:

Code:

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port2.Open(6, 9600, CSerialPort::NoParity, 8, CSerialPort::OneStopBit, CSerialPort::XonXoffFlowControl, TRUE);

    CEvent event(FALSE, TRUE);
    OVERLAPPED overlapped;
    memset(&overlapped, 0, sizeof(overlapped));
    overlapped.hEvent = event;
    try
    {
      port2.Write(pBuf, 10000, overlapped);

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Now I'm thinking to add the following code:

Code:

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char sBuf[] = {0x01,0x02,0x04,0x01,0x02,0x09,0x0c,0x10,0x02,0x06,0x12,0x01,0x01,0x13,0x01,0x01,0x49,0xf1,0x00} ;
        port2.Write(sBuf,sizeof(sBuf)/sizeof(unsigned char),overlapped );
    printf("pBuf %x, \n", sBuf);

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But i don't know if it's correct. Can you help me?

Quote:

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Originally Posted by Bfrancesco

Now I'm thinking to add the following code:

Code:

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char sBuf[] = {0x01,0x02,0x04,0x01,0x02,0x09,0x0c,0x10,0x02,0x06,0x12,0x01,0x01,0x13,0x01,0x01,0x49,0xf1,0x00} ;
        port2.Write(sBuf,sizeof(sBuf)/sizeof(unsigned char),overlapped );
    printf("pBuf %x, \n", sBuf);

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But i don't know if it's correct. Can you help me?

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But why don't you want to try? It would be much faster than write this post to the forum and then wait to the answers!

I'm trying but I don't know if it's correct, because i don't read any error when I compile, but none window appears to read the byte that I send...

This is the complete code:

Code:

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/////////////////////////////////  Includes  //////////////////////////////////

#include "stdafx.h"
#include "SerialPort.h"


///////////////////////////////// Defines /////////////////////////////////////

#ifdef _DEBUG
#define new DEBUG_NEW
#endif


//////////////////////////////// Implementation ///////////////////////////////

class CSerialPortApp : public CWinApp
{
public:
  virtual BOOL InitInstance();
};

CSerialPortApp theApp;

BOOL CSerialPortApp::InitInstance()
{
  BYTE* pBuf = new BYTE[10000];

  try
  {
    COMMCONFIG config;
    CSerialPort::GetDefaultConfig(1, config);

    CSerialPort port;
    port.Open(1, 9600, CSerialPort::NoParity, 8, CSerialPort::OneStopBit, CSerialPort::XonXoffFlowControl);
       
    HANDLE hPort = port.Detach();
    port.Attach(hPort);

    DWORD dwModemStatus;
    port.GetModemStatus(dwModemStatus);

    DCB dcb;
    port.GetState(dcb);

    dcb.BaudRate = 9600;
    port.SetState(dcb);   

    DWORD dwErrors;                     
    port.ClearError(dwErrors);

    port.SetBreak();
    port.ClearBreak();

    COMSTAT stat;
    port.GetStatus(stat);

    DWORD dwBytesWaiting = port.BytesWaiting();
    dwBytesWaiting;

    COMMTIMEOUTS timeouts;
    port.GetTimeouts(timeouts);

    port.Setup(10000, 10000);

    port.GetConfig(config);

    config.dcb.BaudRate = 9600;
    port.SetConfig(config);

    port.Set0WriteTimeout();
    port.Set0ReadTimeout();

    //char sBuf[] = "This should appear on the serial port";
    //port.Write(sBuf, static_cast<DWORD>(strlen(sBuf)));

    DWORD dwMask;
    port.GetMask(dwMask);

    port.SetMask(EV_TXEMPTY);

    //port.WaitEvent(dwMask);

    port.TerminateOutstandingWrites();

    port.TransmitChar('p');

    port.Set0Timeout();

    char sRxBuf[10];
    DWORD dwRead = port.Read(sRxBuf, 10);
    dwRead; //To remove unreferrenced variable in VC 6.

    port.TerminateOutstandingReads();

    port.ClearDTR();

    port.ClearRTS();

    port.SetDTR();

    port.SetRTS();

    port.SetXOFF();

    port.SetXON();

    COMMPROP properties;
    port.GetProperties(properties);

    port.ClearWriteBuffer();

    port.ClearReadBuffer();

    port.Flush();

    port.Close();


    //Try out the overlapped functions
    CSerialPort port2;
    port2.Open(6, 9600, CSerialPort::NoParity, 8, CSerialPort::OneStopBit, CSerialPort::XonXoffFlowControl, TRUE);

    CEvent event(FALSE, TRUE);
    OVERLAPPED overlapped;
    memset(&overlapped, 0, sizeof(overlapped));
    overlapped.hEvent = event;
    try
    {
    //  port2.Write(pBuf, 10000, overlapped);
                char sBuf[19] = {0x01,0x02,0x04,0x01,0x02,0x09,0x0c,0x10,0x02,0x06,0x12,0x01,0x01,0x13,0x01,0x01,0x49,0xf1,0x00} ;
                port2.Write(sBuf,sizeof(sBuf)/sizeof(unsigned char),overlapped );
                printf("pBuf %x, \n", sBuf);
                SleepEx(INFINITE, TRUE);
               
        //  printf("pBuf %x, \n", pBuf);
        }
    catch(CSerialException* pEx)
    {
      if (pEx->m_dwError == ERROR_IO_PENDING)
      {
        DWORD dwBytesTransferred = 0;
        port2.GetOverlappedResult(overlapped, dwBytesTransferred, TRUE);
        pEx->Delete();
      }
      else
      {
        DWORD dwError = pEx->m_dwError;
        pEx->Delete();
        CSerialPort::ThrowSerialException(dwError);
      }
    }
    try
    {
      //port2.Read(pBuf, 10, overlapped);
          port2.Read(pBuf, 20, overlapped);
          SleepEx(INFINITE, TRUE);
          printf("pBuf %x, \n", pBuf);

       
        }
    catch(CSerialException* pEx)
    {
      if (pEx->m_dwError == ERROR_IO_PENDING)
      {
        DWORD dwBytesTransferred = 0;
        port2.GetOverlappedResult(overlapped, dwBytesTransferred, TRUE);
        pEx->Delete();
      }
      else
      {
        DWORD dwError = pEx->m_dwError;
        pEx->Delete();
        CSerialPort::ThrowSerialException(dwError);
      }
    }
         
    port2.SetMask(EV_TXEMPTY);

        /*char sBuf[19] = {0x01,0x02,0x04,0x01,0x02,0x09,0x0c,0x10,0x02,0x06,0x12,0x01,0x01,0x13,0x01,0x01,0x49,0xf1,0x00} ;
        port2.Write(sBuf,sizeof(sBuf)/sizeof(unsigned char),overlapped );
    printf("pBuf %x, \n", sBuf);
        SleepEx(INFINITE, TRUE);
        port2.Read(pBuf, 20);
        SleepEx(INFINITE, TRUE);
        printf("pBuf %x, \n", pBuf);
        */
        /* for testing on NT only
    port2.WriteEx(sBuf, static_cast<DWORD>(strlen(sBuf)));
    SleepEx(INFINITE, TRUE);
        printf("pBuf %x, \n", sBuf);
    port2.ReadEx(pBuf, 10);
    SleepEx(INFINITE, TRUE);
    */

  }
  catch (CSerialException* pEx)
  {
    TRACE(_T("Handle Exception, Message:%s\n"), pEx->GetErrorMessage().operator LPCTSTR());
    pEx->Delete();
  }

  delete [] pBuf;

  return FALSE;
}

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But how did you do it sending non-encoded byte sequence to the serial port?

I'm trying to send encoded bytes (The codification with other code is made). I have understood that to stamp in the MFC application I must use "TRACE" and not "printf", but the real problem is that I'm not understing how i can handle the "BYTE*" and how i can use it in "port.write" to send the bytes.

Did you debug your code to be sure this write() function is called and your byte array is sent to the port?

Quote:

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Originally Posted by Bfrancesco

... the real problem is that I'm not understing how i can handle the "BYTE*" and how i can use it in "port.write" to send the bytes.

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What "BYTE*" do you mean?

1) Why are you first opening port 1, setting various configurations then closing it and opening port 6?
2) Why are you attempting to use overlapped I/O to just send 19 bytes? Why not just write those 19 bytes to the port directly without all the complication of overlapped I/O?

Why not just

Code:

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CSerialPort port2;

    port2.Open(6, 9600, CSerialPort::NoParity, 8, CSerialPort::OneStopBit, CSerialPort::XonXoffFlowControl);

const unsigned char sBuf[] = {0x01,0x02,0x04,0x01,0x02,0x09,0x0c,0x10,0x02,0x06,0x12,0x01,0x01,0x13,0x01,0x01,0x49,0xf1,0x00};

    port2.Write(sBuf, sizeof(sBuf) / sizeof(unsigned char));

    port2.Read(pBuf, 19);

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Get this working first, then if you really need to use overlapped I/O you can start at least with something that works. When trying to do something and you're not quite sure how to do it, start with something as simple as possible, get that working and then expand in small steps to what you are trying to achieve. If you start with something small and working and change it and that change doesn't work then the problem must be only in the change so there is a much narrower area for debuging. You can also undo the changes just made and revert to what was working then try changes again.

Thank you very much 2kaud! now it works correctly!

One question please: I implemented a low-pass filter FIR of 12th order and 5Hz cut-off frequency. I'd like to implement the same filter in c++. Can you suggest something?
Thank you

If you know the algorithm then what is the problem to code it with C++?

I don't know the algorithm. With Matlab I use only this command: B = fir1(N,Wn) where N is the order and the Wn the cut-off frequency.

Then start with learning the algorithm: Wiki

I'd need the algorithm of matlab FIR.

Then ask matlab!

Quote:

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Originally Posted by Bfrancesco

I'd need the algorithm of matlab FIR.

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Can't you use Google?
Just try https://www.google.com/search?source...+FIR&gs_htsa=1
and the first link will point to fir1 - Window-based finite impulse response filter design

In that link there is the equation B(z). Is it sufficient to implement the filter FIR1(N,Wn) in c++?

I have know idea what filter FIR1 is.
It is up to you to find and understand its algorithm and then try to implement it using C++ code.
And no one will do this work for you. Where to search for I already showed you.
If you then will have some problems with C++ - ask in this Forum.

hi,sir what is the code that send byte of binary data from matlab via serial port
thanks in advance

Quote:

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Originally Posted by anasfuad33eng

hi,sir what is the code that send byte of binary data from matlab via serial port
thanks in advance

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1. Please define "from matlab"
2. About how"send byte of binary data... via serial port" / please read this thread from the very begin!