Reading Serial Data from Arduino, Corrupted Data - c++

Question

I am using an Arduino Due and Visual Studio 2010. I am programming in C/C++. Below you see my programs and after this my explanations of what is going wrong.
This is the really simple code thats on my Arduino. Its sending a lot of A's to the PC.
void setup()
{
// initialize serial communication at 9600 bits per second:
Serial.begin(9600);
}
void loop()
{
Serial.println('A');
delay(1); // delay in between reads for stability
}
The further code for reading the Serial Port I found over here:
http://playground.arduino.cc/Interfacing/CPPWindows
And this is my modified version of this code at the moment:
Header:
#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(char *portName);
//Close the connection
//NOTA: for some reason you can't connect again before exiting
//the program and running it again
~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(char *buffer, unsigned int nbChar);
//Check if we are actually connected
bool IsConnected();
};
#endif // SERIALCLASS_H_INCLUDED
CPP:
#include "stdafx.h"
#include <stdio.h>
#include <tchar.h>
#include "SerialClass.h"
#include <string>
#include <windows.h>
#include <assert.h>
#include <stdlib.h>
#include <iostream>
#include <fstream>
#include <conio.h>
using namespace System;
using namespace std;
// Serial::Serial looks, if Serial Connection from PC to the Device is proper and everything is working. Then it sets a few Parameters and waits
Serial::Serial(char *portName)
{
//We're not yet connected
this->connected = false;
//Try to connect to the given port throuh CreateFile
this->hSerial = CreateFileA(portName,
GENERIC_READ | GENERIC_WRITE,
0,
NULL,
OPEN_EXISTING,
FILE_ATTRIBUTE_NORMAL,
NULL);
//Check if the connection was successfull
//if not...show error
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);
Sleep(2000);
}
else
{printf("ERROR!!!");}
}
// else = connection is working, then -> continue
else
{
//If connected we try to set the comm parameters
DCB dcbSerialParams = {0};
//Try to get the current Parameters
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;
//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;
//We wait 2s as the arduino board will be reseting
Sleep(ARDUINO_WAIT_TIME);
}
}
}
}
//Has a look if SerialPort is still connected.
//If yes, it disconnects and closes the Serial Handler.
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);
}
}
// reads data out of Serial Port
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, // Handle to the communications device, CreateFile Function returns this value
&this->errors, // a pointer to a variable that receives a mask indicating the type of rror
&this->status);// a pointer to a COMSTAT structure in which the devices status information is returned. if this parameter is NULL, no status information is returned
//Check if there is something to read
if(this->status.cbInQue>0) // cbInQue: Number of Bytes received by the Serial provider, but not yet read by a ReadFile operation
{
//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, // Handle to a device
buffer, // a pointer to the buffer that receives the data read from a file or device
toRead, // NumberofBytesToRead: the maximum number of bytes to be read
&bytesRead, // NumberofBytesRead: a pointer to the variable that receives the number of bytes read when using a synchronours hFile parameter.
NULL) // Overlapped
&& bytesRead // Value of bytesRead after ReadFile function
!= 0)
{return bytesRead;
Sleep(1000);} // returns Value of BytesRead
}
//If nothing has been read, or that an error was detected return -1
return -1;
}
bool Serial::IsConnected() // simply returns connection status
{
//Simply return the connection status
return this->connected;
}
Main:
// 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("\\\\.\\COM3"); // adjust as needed
if (SP->IsConnected())
printf("We're connected");
// defines how much Data will be catched
// don't forget to pre-allocate memory
char incomingData[1025] = "";
incomingData[1024]='\0';
int dataLength = 1024; // maximum Length of one DataBit/Word
int readResult = 0;
// gives out the Number! of DataBits that could be collected/catched
readResult = SP->ReadData(incomingData,dataLength);
printf("Bytes read: (-1 means no data available) %i\n",readResult);
// transforms the char incomingData into a String and prints it
std::string test(incomingData);
printf("%s \n", incomingData);
printf("Bytes read: (-1 means no data available) %i\n",readResult);
Sleep(10000);
}
So now here is my problem:
The programm works fine, as long as the Amount of Bits I am sending from the Arduino is less than DataLength. (here = 1024) I got those less bits just through setting the Delay from the Arduino programm quite high (~100ms).
Then I have a console window with an Output similar to this:
A
A
A
A
A
... goes on like this
But if the Arduino sends more than 1024 Bits (Delay ~ 1ms)/ the PC receices more Bits than the Value of DataLength, something in the Serial::ReadData Loop seems to get wrong.
My Console Output is than a little bit corrupted and some Bits look like this:
A
ßA
A A
A
... goes on similar to this.
What is wrong with my program? I thought that it could be, that one parameter of the ReadFile() Function is not right, but I do not know what to change and I am not 100% sure about this.