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Re: Struggle with Serial port class [message #27839 is a reply to message #27820]

Fri, 06 August 2010 05:52

jerson
Messages: 202
Registered: June 2010
Location: Bombay, India

Experienced Member

Does anyone know why the Serial::Close() followed by Serial::Open command not work? It seems to hang the code and I have to kill the process to regain control. Is this a Windows quirk?

The problem occurs when I try to change com ports wherein I first close the existing open com port, set new parameters and Open the new com port. If I do not do this, the program always works reliably.

this is the relevant code that is causing me grief

void	CommPak::SetupComms()
{
int Cnt;
int Port,Baud;

	WithCommSetup<TopWindow>	CommSetup;

	// stop the timer before changing anything
	if (ExistsTimeCallback(idRxTimer))
	{
		KillTimeCallback(idRxTimer);
		PromptOK("Killed the timer");
	}

	// if the port is open, close it
	if (CommPort.IsOpened())	CommPort.Close();
	
	CtrlLayoutOKCancel(CommSetup, "Setup Comms");
	for (Cnt=1;Cnt < 9;Cnt++)
		CommSetup.dlPort.Add(Format("COM%d",Cnt));
	CommSetup.dlBaud.Add("1200");
	CommSetup.dlBaud.Add("2400");
	CommSetup.dlBaud.Add("4800");
	CommSetup.dlBaud.Add("9600");
	CommSetup.dlBaud.Add("19200");
	
	CommSetup.dlPort = "COM6";	// choose to display COM6
	CommSetup.dlBaud= "9600";	// and 9600 baud
	
	if (CommSetup.Execute() == IDOK)
	{
		Port = CommSetup.dlPort.GetIndex()+1;
		Baud = CommSetup.dlBaud.GetIndex();
		DUMP(Port);
		DUMP(Baud);
		
		// Now open the port at the baud rate
		if (!CommPort.Open(Port,Baud))
			PromptOK(Format("Cannot open COM%d",Port));
		else
		{
			PromptOK(Format("COM%d opened successfully",Port));
			SetTimeCallback(-100,THISBACK(CheckRxTmr), idRxTimer);
		}		
	}
}

Thanks

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