串行通讯问题

Question

I'm making a project which works with an Arduino via USB. I'm using nearly the same code which was in the library I am using.

The code reads a .txt file, and sends this data to the Arduino in an infinite loop. The problem is that after the 165th loop, it really slows down. It takes the connection 6 seconds to send 6 characters. Always at 165. Here is the code:

while(SP->IsConnected()) {
  //see if the usb connection is on.
  fstream file;
  file.open("c:/Python27/beki.txt");
  for(int i=0;i<6;i++) {
    file >> incomingData[i];
    cout << incomingData[i];
  }
  file.close();
  cout <<szam << "\n";
  SP->WriteData(incomingData,dataLength);
  szam++; //counting, thats why i know its always slows at 166.
  Sleep(200);
}

I figured out that it's not the file, and it does not eat much memory, 335k. And it sends good data, so until the 165th loop, it does its work perfectly. The file is written by another infinite loop, and after this 165th loop, the code sends old data's characters.

It did the same in Python. I don't know if there's a limit or something. Please help.

I'm using this library .

Answer 1

You need to bring the following outside of your while loop:

fstream file;
file.open("c:/Python27/beki.txt");

and

file.close();

As it is now, you are probably sending the same bytes after opening the file each time.