As I found it pretty hard finding the good information, or an already working code to handle Serial communication on windows based system, I finally made a class that do what is needed for basic Serial Communication, thanks to help of several forumers. Please note that this code might not be completely perfect so I encourage you to make any update needed so that it might become even better.
So now for the code which is consisting of two files, a header and a source code file.
Click here for an easy example using Visual Studio 2008 Express.
Important note: when connecting to some Arduinos, it is necessary to use COM port "device names" as outlined at http://forum.arduino.cc/index.php?topic=20149.msg148538#msg148538.
Furthermore: When addressing ports larger than COM9 in Windows you will have to specify the port thusly: "COM10" becomes "\\\\.\\COM10" See: http://support.microsoft.com/default.aspx?scid=kb;EN-US;q115831
And: CreateFile may need to be replaced with CreateFileA in Serial.cpp
#ifndef SERIALCLASS_H_INCLUDED
#define SERIALCLASS_H_INCLUDED
#define ARDUINO_WAIT_TIME 2000
#include <windows.h>
#include <stdio.h>
#include <stdlib.h>
class Serial
{
private:
//Serial comm handler
HANDLE hSerial;
//Connection status
bool connected;
//Get various information about the connection
COMSTAT status;
//Keep track of last error
DWORD errors;
public:
//Initialize Serial communication with the given COM port
Serial(const char *portName);
//Close the connection
~Serial();
//Read data in a buffer, if nbChar is greater than the
//maximum number of bytes available, it will return only the
//bytes available. The function return -1 when nothing could
//be read, the number of bytes actually read.
int ReadData(char *buffer, unsigned int nbChar);
//Writes data from a buffer through the Serial connection
//return true on success.
bool WriteData(const char *buffer, unsigned int nbChar);
//Check if we are actually connected
bool IsConnected();
};
#endif // SERIALCLASS_H_INCLUDED
#include "SerialClass.h"
Serial::Serial(const char *portName)
{
//We're not yet connected
this->connected = false;
//Try to connect to the given port throuh CreateFile
this->hSerial = CreateFile(portName,
GENERIC_READ | GENERIC_WRITE,
0,
NULL,
OPEN_EXISTING,
FILE_ATTRIBUTE_NORMAL,
NULL);
//Check if the connection was successfull
if(this->hSerial==INVALID_HANDLE_VALUE)
{
//If not success full display an Error
if(GetLastError()==ERROR_FILE_NOT_FOUND){
//Print Error if neccessary
printf("ERROR: Handle was not attached. Reason: %s not available.\n", portName);
}
else
{
printf("ERROR!!!");
}
}
else
{
//If connected we try to set the comm parameters
DCB dcbSerialParams = {0};
//Try to get the current
if (!GetCommState(this->hSerial, &dcbSerialParams))
{
//If impossible, show an error
printf("failed to get current serial parameters!");
}
else
{
//Define serial connection parameters for the arduino board
dcbSerialParams.BaudRate=CBR_9600;
dcbSerialParams.ByteSize=8;
dcbSerialParams.StopBits=ONESTOPBIT;
dcbSerialParams.Parity=NOPARITY;
//Setting the DTR to Control_Enable ensures that the Arduino is properly
//reset upon establishing a connection
dcbSerialParams.fDtrControl = DTR_CONTROL_ENABLE;
//Set the parameters and check for their proper application
if(!SetCommState(hSerial, &dcbSerialParams))
{
printf("ALERT: Could not set Serial Port parameters");
}
else
{
//If everything went fine we're connected
this->connected = true;
//Flush any remaining characters in the buffers
PurgeComm(this->hSerial, PURGE_RXCLEAR | PURGE_TXCLEAR);
//We wait 2s as the arduino board will be reseting
Sleep(ARDUINO_WAIT_TIME);
}
}
}
}
Serial::~Serial()
{
//Check if we are connected before trying to disconnect
if(this->connected)
{
//We're no longer connected
this->connected = false;
//Close the serial handler
CloseHandle(this->hSerial);
}
}
int Serial::ReadData(char *buffer, unsigned int nbChar)
{
//Number of bytes we'll have read
DWORD bytesRead;
//Number of bytes we'll really ask to read
unsigned int toRead;
//Use the ClearCommError function to get status info on the Serial port
ClearCommError(this->hSerial, &this->errors, &this->status);
//Check if there is something to read
if(this->status.cbInQue>0)
{
//If there is we check if there is enough data to read the required number
//of characters, if not we'll read only the available characters to prevent
//locking of the application.
if(this->status.cbInQue>nbChar)
{
toRead = nbChar;
}
else
{
toRead = this->status.cbInQue;
}
//Try to read the require number of chars, and return the number of read bytes on success
if(ReadFile(this->hSerial, buffer, toRead, &bytesRead, NULL) )
{
return bytesRead;
}
}
//If nothing has been read, or that an error was detected return 0
return 0;
}
bool Serial::WriteData(const char *buffer, unsigned int nbChar)
{
DWORD bytesSend;
//Try to write the buffer on the Serial port
if(!WriteFile(this->hSerial, (void *)buffer, nbChar, &bytesSend, 0))
{
//In case it don't work get comm error and return false
ClearCommError(this->hSerial, &this->errors, &this->status);
return false;
}
else
return true;
}
bool Serial::IsConnected()
{
//Simply return the connection status
return this->connected;
}
That's all you need, it has been tested with CodeBlocks and the MinGW compiler but should work fine with Visual Studio too. As for the way to use it I think the comments of the header makes it quite simple to understand though if needed you can contact me on the forum.
This example builds on the serial_read_blink.pde sketch that is included in the Arduino + C example on the Interfacing With Software page. You need to have Visual Studio 2008 C++ Express Edition or the full version of Visual Studio 2008 C++ installed on your computer.
this->serialPort1->PortName = "COM5"; // Replace with your COM port!
this->serialPort1->Open();
this->serialPort1->Write( "7" ); // In the future, you'll expand on this
// to write your custom data to the board
this->serialPort1->Close();
Note: serialPort1 is the default name of the object, and if you change it, you'll need to change this code.
#include <stdio.h>
#include <tchar.h>
#include "SerialClass.h" // Library described above
#include <string>
// application reads from the specified serial port and reports the collected data
int _tmain(int argc, _TCHAR* argv[])
{
printf("Welcome to the serial test app!\n\n");
Serial* SP = new Serial("\\\\.\\COM10"); // adjust as needed
if (SP->IsConnected())
printf("We're connected");
char incomingData[256] = ""; // don't forget to pre-allocate memory
//printf("%s\n",incomingData);
int dataLength = 255;
int readResult = 0;
while(SP->IsConnected())
{
readResult = SP->ReadData(incomingData,dataLength);
// printf("Bytes read: (0 means no data available) %i\n",readResult);
incomingData[readResult] = 0;
printf("%s",incomingData);
Sleep(500);
}
return 0;
}