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Editorial Team
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Asked: 2026-05-26T12:42:47+00:00

I have my code that reads and writes to a serial port written in

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I have my code that reads and writes to a serial port written in MFC. The programs works well but is a bit slow as there are many operations occuring (Read and writing). I have a timer that carries on the operations on the serial port. The timer is given below:

Loop_Timer = SetTimer(1,50,0);

The serial port transmission information is as follows:

BaudRate = 57600;
ByteSize = 8;
Parity = NOPARITY;
StopBits = ONESTOPBIT;
fAbortOnError = false;

The following write and read operation occurs when the timer starts:

Write(command);
Read(returned_message);
returned_message.Trim();
...   
//finds a value from the returned string
...

So, this read and write operation occurs may be 1,2,3 or 4 times for a given selected option.

For Ex: Option 1 requires the above function to occurs 4 times in the given timer.
Option 2 requires the above function to occur 2 times. (as it has only two variables with return values). etc
…

Now, what I was trying to do is improving the speed of this overall operation making it robust and respond quickly. I tried changing the timer but it is still pretty slow. Any suggestions on improvement?

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1 Answer

  1. Editorial Team

    You’d do far better to run your actual serial port processing in a separate thread, and to use the WaitCommEvent rather than a timer for accepting incoming data. Append newly received data within a storage buffer local to that thread.

    Retrieve data from your serial port thtread using a timer if you wish, or have your serial port thread communicate to your main app. when a complete message is received.

    When sending data to the serial port thread you want a mechanism, whereby the data is stored locally to the serial port code and transmitted form there.

    The thing to bear in mind is that compared to all other means of communications serial port transmission and reception is SLOW and by accessing the serial port on your main application thread you’ll slow it down massively, especially when transmitting data.

    If you find direct coding using the Win32 API and serial ports a pain then this class here I’ve found very useful.

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