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POUnable to receive data from serial port
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copied!<p>Currently I try to write a serial port communication in VC++ to transfer data from PC and robot via XBee transmitter. But after I wrote some commands to poll data from robot, I didn't receive anything from the robot (the output of filesize is 0 in the code.). Because my MATLAB interface works, so the problem should happen in the code not the hardware or communication. Would you please give me help? </p> <p>01/03/2014 Updated: I have updated my codes. It still can not receive any data from my robot (the output of read is 0). When I use "cout<<&read" in the while loop, I obtain "0041F01C1". I also don't know how to define the size of buffer, because I don't know the size of data I will receive. In the codes, I just give it a random size like 103. Please help me.</p> <pre><code>// This is the main DLL file. #include "StdAfx.h" #include <iostream> #define WIN32_LEAN_AND_MEAN //for GetCommState command #include "Windows.h" #include <WinBase.h> using namespace std; int main(){ char init[]=""; HANDLE serialHandle; // Open serial port serialHandle = CreateFile("\\\\.\\COM8", GENERIC_READ | GENERIC_WRITE, 0, 0, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0); // Do some basic settings DCB serialParams; DWORD read, written; serialParams.DCBlength = sizeof(serialParams); if((GetCommState(serialHandle, &serialParams)==0)) { printf("Get configuration port has a problem."); return FALSE; } GetCommState(serialHandle, &serialParams); serialParams.BaudRate = CBR_57600; serialParams.ByteSize = 8; serialParams.StopBits = ONESTOPBIT; serialParams.Parity = NOPARITY; //set flow control="hardware" serialParams.fOutX=false; serialParams.fInX=false; serialParams.fOutxCtsFlow=true; serialParams.fOutxDsrFlow=true; serialParams.fDsrSensitivity=true; serialParams.fRtsControl=RTS_CONTROL_HANDSHAKE; serialParams.fDtrControl=DTR_CONTROL_HANDSHAKE; if (!SetCommState(serialHandle, &serialParams)) { printf("Set configuration port has a problem."); return FALSE; } GetCommState(serialHandle, &serialParams); // Set timeouts COMMTIMEOUTS timeout = { 0 }; timeout.ReadIntervalTimeout = 30; timeout.ReadTotalTimeoutConstant = 30; timeout.ReadTotalTimeoutMultiplier = 30; timeout.WriteTotalTimeoutConstant = 30; timeout.WriteTotalTimeoutMultiplier = 30; SetCommTimeouts(serialHandle, &timeout); if (!SetCommTimeouts(serialHandle, &timeout)) { printf("Set configuration port has a problem."); return FALSE; } //write packet to poll data from robot WriteFile(serialHandle,">*>p4",strlen(">*>p4"),&written,NULL); //check whether the data can be received char buffer[103]; do { ReadFile (serialHandle,buffer,sizeof(buffer),&read,NULL); cout << read; } while (read!=0); //buffer[read]="\0"; CloseHandle(serialHandle); return 0; } </code></pre>

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