Serial RS232 thread interupt problems

[ugly]

Serial RS232 thread interupt problems


I am trying to get two computers to communicate to each other via a RS232 communication link. Hyperterminal is running on computer A and my executable is running on computer B. My exec is a simple dialog based app. The user ticks a box on the dialog which invokes “OnCheck1() . Within OnCheck() I create a new thread that calls the function ThreadProc(), this does get called but I cannot enter the if statement when there is activity on hyperterminal. I can succesfully send info from my machine B to hyperterminal running on machine A using “OnSend”. However if I type into hyperterminal I am unable to detect it within my app. The following code has been entered in my dialog class.
Can any one pleazzze help, I been told not to use any of the various encapsulated serial classes floating around on the internet.


// this does its job ok
void CSerialPROTO1Dlg::OnSend()
{
UpdateData(TRUE);
// TODO: Add your control notification handler code here
unsigned long dwBytesWritten;

CString hod = m_message;


if(!WriteFile(hPort,static_cast<LPCTSTR>(hod),hod.GetLength(),&dwBytesWritten,NULL))
{
MessageBox(&quot;unable to write to port&quot;
}
else
{
MessageBox(&quot; written to port&quot;
}
}


HANDLE hPort;

UINT ThreadProc(LPVOID param)
{

DWORD dwCommModemStatus;
::MessageBox((HWND) param ,&quot;thread activated&quot;,&quot;thread&quot;,MB_OK);
SetCommMask(hPort,EV_RXCHAR);
EV_RXCHAR;
while(hPort!= INVALID_HANDLE_VALUE)
{

WaitCommEvent(hPort,&dwCommModemStatus,0);
SetCommMask(hPort,EV_RXCHAR);

// PROBLEMS PROBLEMS
if(dwCommModemStatus & EV_RXCHAR)
{
::MessageBox((HWND) param ,&quot;activity on port &quot;,&quot;thread&quot;,MB_OK);


}

}



return 0;

}


void CSerialPROTO1Dlg::OnCheck1()
{

UpdateData(TRUE);

hPort = CreateFile(&quot;COM1:&quot; ,GENERIC_READ|GENERIC_WRITE,0,NULL,OPEN_EXISTING,0
,NULL);
if ( hPort == INVALID_HANDLE_VALUE)
{

MessageBox (&quot;Unable to open the port&quot;
//return FALSE;
}
else
{
MessageBox(&quot;port opened&quot;
}

// configure the propertities of the port

DCB PortDCB;
PortDCB.DCBlength = sizeof(DCB);
GetCommState(hPort,&PortDCB);
PortDCB.BaudRate = 2400;
PortDCB.fBinary = TRUE;
PortDCB.fParity = TRUE;
PortDCB.fDtrControl = DTR_CONTROL_ENABLE;
PortDCB.fOutxCtsFlow = FALSE;
PortDCB.fOutxDsrFlow = FALSE;
PortDCB.fDsrSensitivity = FALSE;
PortDCB.fTXContinueOnXoff = TRUE;
PortDCB.fOutX = FALSE;
PortDCB.fInX = FALSE;
PortDCB.fErrorChar = FALSE;
PortDCB.fNull = FALSE;
PortDCB.fRtsControl = RTS_CONTROL_ENABLE;
PortDCB.fAbortOnError = FALSE;
PortDCB.ByteSize = 8;
PortDCB.Parity = NOPARITY;
PortDCB.StopBits = ONESTOPBIT;
if(!SetCommState(hPort,&PortDCB))
{
MessageBox(&quot;unable to configure the port&quot;
}
else
{
MessageBox(&quot;port configured&quot;
}


// set the time out for the transmission


COMMTIMEOUTS CommTimeouts;
GetCommTimeouts (hPort, &CommTimeouts);
// change the commtimeouts structure settings

CommTimeouts.ReadIntervalTimeout= MAXDWORD;
CommTimeouts.ReadTotalTimeoutMultiplier = 0;
CommTimeouts.WriteTotalTimeoutConstant = 0;
CommTimeouts.WriteTotalTimeoutMultiplier = 10;
CommTimeouts.WriteTotalTimeoutConstant = 1000;
// set the time out parameters for the port


if(!SetCommTimeouts(hPort, &CommTimeouts))
{
MessageBox(&quot;unable to set the time out parameters&quot;
this->EnableWindow(FALSE);
}

else
{
MessageBox(&quot;configured the time&quot;
}
// line is now open to write data down the serial RS232 line

HWND hWnd = GetSafeHwnd();
AfxBeginThread(ThreadProc,hWnd,THREAD_PRIORITY_NO
RMAL);


}

 

[palbano]

>> Can any one pleazzze help, I been told not to use any of
>> the various encapsulated serial classes floating
>> around on the internet.

Who told you and did they explain why? (By who I mean do they know what they are talking about)

So it's been many years so this may not help at all... but try reversing these lines

>> WaitCommEvent(hPort,&dwCommModemStatus,0);
>> SetCommMask(hPort,EV_RXCHAR);


SetCommMask(hPort,EV_RXCHAR);
WaitCommEvent(hPort,&dwCommModemStatus,0);


Good luck
-pete

 

[EarlAllen]

Be sure the flow control (RTS-CTS, XOn-XOff, None) is set properly on both computers. Also, if using RTS-CTS, be sure that the CTS signal is on. Likewise, if using XON-XOFF, be sure XON has been sent.

I would highly recommend the Serial Library version 1.03 found on The Code Project. I used it recently to connect to an Optical Mark Reader (ie bubble scanner). At one point, I adapted the nine pin cable back to a twenty-five pin cable so I could read the wire signals on an RS232 Serial Breakout Box I bought fifteen years ago.