Using MSCOMM within VC++

[chris2001a]

Hi,

I've been trying, for a few days now, to use the MSCOMM OLE control to use the serial port on my PC. I'm trying to get&send data from one port to another one.
I have 2 Edit Boxes and 2 MSCOMM (one for each port).
Both COM have the same settings. Now to test it, I use the hyperterminal and turn a com port off.
What I don't understand is how I can receive the data and print them in the edit box(it seems it only sends them...). Also I notice that the data in the edit box are sent a bit late. I mean I have to press 2 keys to see the first one appearing in the hyperterminal.

I'd appreciate if some could send me docs, info or even code to do such thing in Visual C++.

Thanks,

Chris.

 

[kedrew]

Chris -

Have you looked at MSDN's VCTerm example? I found it to be a good starting point.

Briefly, assuming you do not poll for data on the serial port, you will need to add a 'OnCommEvent' function with the appropriate 'Event Sink Map'. Inside of the 'oncommevent' function, after reading the data you will need to 'UpdateData(false)'.

Hope this helps you.

 

[chris2001a]

kedrew,

Ok, I'll try to find this example. (I would appreciate if you could give me alink though

)

I have the OnCommEvent() on both port, I'm not quite sure when it gets called. I have placed a TRACE() to see when it gets call and nothing! Well except when the connection is made not when transferring or getting data...
I know I can send data (from COM1) to a hyperterminal set on COM2 ('cos I see them on the hyperterminal). But it doesn't work the other way around...

BTW, I just found out my edit box problem which was due to the UpdateData() call I was doing.

Thanks,
Chris.

 

[kedrew]

Chris -

Just do a search for VCTerm on 'msdn.microsoft.com' or the MSDN CD set. I'd give you the URL, but I cannot easily pull the link out of the site.

You may be missing one setup item to enable the event to trigger, at least that's what I can make out of my comments that were probably copied from VCTerm. m_commctrl is the name of the control.

// Set RThreshold property to 1. The default RThreshold value (0)
// causes the OnComm event to NOT fire when a character is detected
// in the serial port.
m_commctrl.SetRThreshold(1);

Let me know if you are still having difficulties after finding the example and I will get you a stripped down example.

 

[chris2001a]

Yeah, that was the one and my very simple app is now running.

Thanks kedrew.