Help Needed for CSerialPort v1.27

[Kappa3141]

I'm trying to get a C++ MFC SDI working using VS 2008 which takes a 6-bit binary value sent from a PIC16f877a through an RS232 line to a GUI. All I need the GUI to do is display the value sent to it, by an event handler on a button. I'm using Naughter's CSerialPort v1.27 (http://www.naughter.com/serialport.html).

So my code compiles ok, but doesn't display anything. I'm a complete beginner to C++ and MFC but this is the code I have for the event handler:

void CWECSGUI10View::OnBnClickedBtnVlt()
{
	// TODO: Add your control notification handler code here

	try
	{

	// opens comport 1
	CSerialPort port;
    port.Open(1, 115200, CSerialPort::NoParity, 8,
		CSerialPort::OneStopBit,
		CSerialPort::XonXoffFlowControl, TRUE);

	// reads RS232 input
	port.Read(m_Voltin,1);

	// display data
	CString strVoltage;
	double voltage;
	strVoltage.Format(_T("%.3f"), voltage);
	this->m_Voltin.SetWindowTextW(strVoltage);

	port.Flush();
	port.Close();

	}

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

	pEx->Delete();
	}

}

What am I doing wrong and how can I correct it?


Just to make the information complete, on the PIC side of things I'm compiling with BoostC. My code has been verified with another app to send a 6-bit value through a 10-bit ADC module but here it is anyway:

#include <rs232_driver.h>
#include <adc.h>

.... default configuration etc ...

	while( 1 )
	{
		voltage = adc_measure(0)>>4;
		delay_ms( 250 );
		uart_init(1,10); 
   		putc(voltage);
	}

Also to make the information complete, I added the m_Voltin variable to the form class as a public control edit variable.

[Skizmo]

port.Read(m_Voltin,1);

the Read function expects a void* (that needs to be a char buffer, i guess), not a pointer to a GUI component.

DWORD Read(void* lpBuf, DWORD dwCount);

[Kappa3141]

port.Read(m_Voltin,1);

the Read function expects a void* (that needs to be a char buffer, i guess), not a pointer to a GUI component.

DWORD Read(void* lpBuf, DWORD dwCount);

Yeah I've tried variations of this such as:

DWORD Read(m_Voltin, DWORD dwCount);

etc but can't get anything to display. Also lots of variations of:

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

(which is from the example app provided with the code) such as

DWORD dwRead = port.Read(m_Voltin, 1);
dwRead; //To remove unreferrenced variable in VC 6.

but still can't get it to display.

[Skizmo]

char sRxBuf[10];
DWORD dwRead = port.Read(sRxBuf, 10);

This is good.

But your actual display never uses the 'sRxBuf'.

CString strVoltage;
double voltage;
strVoltage.Format(_T("%.3f"), voltage);
this->m_Voltin.SetWindowTextW(strVoltage);

put the 'sRxBuf' in 'voltage' and you should see something.

[Kappa3141]

put the 'sRxBuf' in 'voltage' and you should see something.

I did that and still nothing. When I look at the output window I'm getting the following error message whenever I press the button:

CSerialPort::Read, Failed in call to ReadFile, Error:87
Warning: throwing CSerialException for error 87
First-chance exception at 0x7c812aeb in WECSGUI10.exe: Microsoft C++ exception: CSerialException at memory location 0x0012f3fc..
Handle Exception, Message:The parameter is incorrect.

[VictorN]

... I'm getting the following error message whenever I press the button:

CSerialPort::Read, Failed in call to ReadFile, Error:87
Warning: throwing CSerialException for error 87
First-chance exception at 0x7c812aeb in WECSGUI10.exe: Microsoft C++ exception: CSerialException at memory location 0x0012f3fc..
Handle Exception, Message:The parameter is incorrect.

Sure it is incorrect. Because you defined it wrong (or you passed in the wrong parameter):

... I added the m_Voltin variable to the form class as a public control edit variable.

Please have a look at the code example that Skizmo has provided you in the post#4.

[Kappa3141]

Sure it is incorrect. Because you defined it wrong (or you passed in the wrong parameter):

I realise that. How can I correct this?

Please have a look at the code example that Skizmo has provided you in the post#4.

Er sorry but I did that already. In my previous post I said that I tried to replace the voltage variable with sRxBuf. This is what I then used:

CString strVoltage;
//double voltage;
strVoltage.Format(_T("%.3f"), sRxBuf);
this->m_Voltin.SetWindowTextW(strVoltage);

Please remember I am a beginner!

control edit variable

I have absolutely no idea what you mean by pointing this out.

[MikeAThon]

If this line compiled:

port.Read(m_Voltin,1);

then since Read() wants a void* then it's unlikely that m_voltin is a "public control edit variable", as indicated in the first post.

Please post the definition of m_Voltin. It might actually be a CString that's DDX'd to an edit control.

If so, then try this:

char sRxBuf[11];
DWORD dwRead = port.Read(sRxBuf, 10);
sRxBuf[10] = 0;

CString strVoltage;
strVoltage.Format(_T("dwRead = %d: sRxBuf = %s"), dwRead, sRxBuf);
m_Voltin = strVoltage;
UpdateData( FALSE );

Note that your original format code of T("%.3f") doesn't make any sense, since you were reading only a single byte from the serial port, which can't possibly be converted by the Format() function into a float.

Mike

[newborn2]

how to convert the m_Voltin in CString to double so that we can manipulate the data further?

[VictorN]

how to convert the m_Voltin in CString to double so that we can manipulate the data further?

If *your* m_Voltin is of a CString type and it contains a text corresponding some double variable then

double dbl = _tcstod(m_Voltin);

[newborn2]

I'm try to implement that code... but the problem is the m_Voltin is in another dialogue... I use the same method but clicking some button but my control edit is in another dialogue that being pop up...

[VictorN]

I cannot help you without seeing your actual code.

[newborn2]

this is what I'm doing.. below is my code. when I push Readpot button, the another dialogue will pop up which consists of 2 edit control box named m_Voltin1 and m_Voltin2 which double type data...

the pop up dialogue name is IDD_Potentiometer with CPotentiometer class while the main dialogue is IDD_My3DbalanceDlg with CMy3DbalanceDlg class.

both data are read from PIC (COMPort). thats why I ask for the conversion from CString to double.

Then, I want to transfer the double type data to main dialogue by create the code below:

---------------------------------------------------------------------------------------------------
void CMy3DbalanceDlg::OnBnClickedReadpot()
{
CPotentiometer dlg;

dlg.m_Voltin1=AngleX;
dlg.m_Voltin2=AngleZ;


if( IDOK == dlg.DoModal() )

{
UpdateData();

AngleX=dlg.m_Voltin1;
AngleZ=dlg.m_Voltin2;

UpdateData(FALSE);
}


}

[newborn2]

the AngleX and AngleZ is the double type data define in the main dialogue..

[newborn2]

I'm use the (http://www.naughter.com/serialport.html) code and include the .cpp file and h file into my project. I'm just include the SerialPort.h header file in my main IDD_My3DbalanceDlg.cpp. Where I should put the COMPort setup like above? in the IDD_My3DbalanceDlg.cpp or IDD_Potentiometer.cpp?