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Serial Communication for WIN32

by Thierry Schneider, April 8th 2001
revised April 14th 2001, minor corrections
revised April 24th 2001, modification for Visual C++
revised April 29th 2001, correction of bugs that occured during reconnection

Foreword: If you experience any problem using this software, please be sure that you have the latest version. Check our web site www.tetraedre.com for an updated version of the software.
Otherwise report any bug to the address above or check the FAQ

Each programmer knows that accessing the hardware ports of a computer is getting more and more complicated. The software presented here intends to ease the development of applications using the serial port (COM) on computer running Windows 32-bits operating systems.

Allen Denver, from the Microsoft Windows Developer Support wrote one of the only technical article describing in details how to use the serial port under Win32. This article can be downloaded on Microsoft's web site. A copy of this article can also be found here.
 
 

From that article, I've written two different software packages. One for what I call "non-event-driven" applications. This means simple applications like console applications,... The other package is intended to be used in event-driven applications (like GUI and other windows stuff).

All software and documentation described here can be downloaded directly here : serial.zip
 

If you have questions, don't hesitate to send me an email (developer@tetraedre.com) and/or visit our website (www.tetraedre.com) to read the FAQ (look inside the developer's corner)
 
 

Compilation with Borland C++ Builder

The ZIP file contains two Borland C++ project files (sertest.bpr and sertest2.bpr). Simply open them, compile, run and enjoy !
 

Compilation with Microsoft Visual C++

The project was originally created to be compiled with the Borland C++ Builder development environment. In order to permit compilation  with Microsoft's Visual C++, I've modified a little the source code. A "#ifdef __BORLANDC__" has been inserted in the header part of the sertest.cpp and sertest2.cpp files in order to skip some Borland's specific pre-compiler commands.

IMPORTANT
But more important. The event-driven application uses multithreading in order to generate the events. So Visual C++ projects that use multithreading must be compiled with the appropriate setting. In your project settings, you MUST choose the multithreaded run-time library, otherwise the programme will not compile
 
 

Project settings
    |
    *--- C/C++
           |
           *--- Code generation
                        |
                        *---- Use run-time library
                                      |
                                      *---- Multithreaded

Software package for non-event-driven applications

Once you have read Allen Denver's article everything is getting clear, so the source files provided here is simply auto-documented. I've written clear software with a very simple example that should be sufficient to understand well the software.
The following table given an overview of the functions the application can use. As we see, these one are very simple and allow the writting of small application that access the serial port.

You may download the following files:

tserial.h	Header file for the serial communication object
tserial.cpp	C++ source file for the serial communication object
sertest2.cpp	Simple application using the serial communication object

 

Function	Description
Tserial()	Object creation
~Tserial()	Object destruction
int connect (char *port_arg, int rate_arg, serial_parity parity_arg)	Serial port setup and start of connection port_arg : "COM1", "COM2", ... rate_arg : 19200, 9600, ... parity_arg : spNONE, spODD, spEVEN Returns 0 if no error occured
void sendChar (char c)	Send a char on the serial line. Blocks until it is sent
void sendArray (char *buffer, int len)	Send an array of char on the serial line. Blocks until it is sent
char getChar (void)	Returns the next char from the input buffer. Blocks if no data is available
int getArray (char *buffer, int len)	Returns an array from the input buffer. Blocks until (some) data are available. The returned parameter indicates how many bytes have been read
int getNbrOfBytes (void)	Returns the number of bytes waiting in the input buffer
void disconnect (void)	Disconnect the serial port

Software package for event-driven applications

The non-event-driven software package is composed mainly of blocking function. In the event-driven world this is unacceptable.
You will note that this software package doesn't manage messages (or string) but works only on a byte by byte manner. You may also be surprised to discover the OnCharSent event. This is due to the fact that this software package was used in the development of embedded applications. So the OnCharSent event is similar to the "Tx buffer empty" interrupt of most of UART.

You may download the following files:

tserial_event.h	Header file for the serial_event communication object
tserial_event.cpp	C++ source file for the serial_event communication object
sertest.cpp	Simple application using the serial_event communication object

 
 

Methods

Function	Description
Tserial_event()	Object creation
~Tserial_event()	Object destruction
int connect (char *port_arg, int rate_arg, serial_parity parity_arg)	Serial port setup and start of connection port_arg : "COM1", "COM2", ... rate_arg : 19200, 9600, ... parity_arg : spNONE, spODD, spEVEN Returns 0 if no error occured
void sendChar (char c)	Send a char on the serial line. Once the byte is sent, the OnCharSent event is called
int getNbrOfBytes (void)	Returns the number of bytes waiting in the input buffer
void disconnect (void)	Disconnect the serial port.
void setManagerOnCharArrival(type_charEvent manager)	This function indicates to the serial object which function must be called when the OnCharArrival event occurs. The manager parameter is the name of the function to call
void setManagerOnConnected(type_voidEvent manager)	This function indicates to the serial object which function must be called when the OnConnected event occurs. The manager parameter is the name of the function to call
void setManagerOnDisconnected(type_voidEvent manager)	This function indicates to the serial object which function must be called when the OnDisconnected event occurs. The manager parameter is the name of the function to call
void setManagerOnCharSent(type_voidEvent manager)	This function indicates to the serial object which function must be called when the OnCharSent event occurs. The manager parameter is the name of the function to call

 
 
 
 

Events

Function	Description
void OnCharArrival (char c)	This event occurs when a byte is received on the serial communication port. This function is very similar to the "RX buffer full" interrupt of some UART
void OnConnected (void)	This event occurs when the serial object is started
void OnDisconnected (void)	This event occurs when the serial object is stopped
void OnCharSent (void)	This event occurs when the byte has been sent. This function is very similar to the "TX buffer empty" interrupt of some UART

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