I am working on an embeeded device.and it is connected on COM6 port
when i use putty to write to that port it replies me with result.
example is when you say hello,it replies hello.
I wrote a program to write to COM6,i am able to write to the COM6 port but when i am reading i am not getting anything.
my code is...
// HelloWorld.cpp : Defines the entry point for the console application. //
#include "stdafx.h"
#include <iostream>
#include <windows.h>
int main()
{
using namespace std;
// cout << "Hello world!" << endl;
HANDLE hSerial;
hSerial = CreateFile("COM6",
GENERIC_READ | GENERIC_WRITE,
FILE_SHARE_WRITE | FILE_SHARE_READ,
0,
OPEN_EXISTING,
FILE_ATTRIBUTE_NORMAL,
0);
if(hSerial==INVALID_HANDLE_VALUE)
{
if(GetLastError()==ERROR_FILE_NOT_FOUND)
{
// TRACE("serial port does not exist for reading\n");
//serial port does not exist. Inform user.
}
// TRACE("some other error,serial port does not exist for reading\n");
//some other error occurred. Inform user.
}
DCB dcbSerialParams = {0};
dcbSerialParams.DCBlength=sizeof(dcbSerialParams);
if (!GetCommState(hSerial, &dcbSerialParams))
{
// TRACE("error getting state for reading\n");
//error getting state
}
dcbSerialParams.BaudRate=9600;
dcbSerialParams.ByteSize=8;
dcbSerialParams.StopBits=ONESTOPBIT;
dcbSerialParams.Parity=NOPARITY;
if(!SetCommState(hSerial, &dcbSerialParams))
{
// TRACE("error setting state for reading\n");
//error setting serial port state
}
COMMTIMEOUTS timeouts={0};
timeouts.ReadIntervalTimeout=50;
timeouts.ReadTotalTimeoutConstant=50;
timeouts.ReadTotalTimeoutMultiplier=10;
timeouts.WriteTotalTimeoutConstant=50;
timeouts.WriteTotalTimeoutMultiplier=10;
if(!SetCommTimeouts(hSerial, &timeouts))
{
// TRACE("some error occured for reading\n");
//error occureed. Inform user
}
int n=100;
char szBuff[100];
DWORD dwBytesRead = 0;
char szBuff1[100]="LIST";
DWORD dwByteswrote = 0;
if(!WriteFile(hSerial, szBuff1, n, &dwByteswrote, NULL))
{
cout << "error writing" ;
}
cout << dwByteswrote;
while(1)
{
if(!ReadFile(hSerial, szBuff, n, &dwBytesRead, NULL))
{
cout << "error re开发者_如何学Cading";
}
else
{
cout << dwBytesRead;
if(dwBytesRead>0)
{
cout << szBuff;
break;
}
}
}
}
Can anyone help me in this?? what is the wrong thing i am making??
It might be that you have to send a "line feed" or a "carriage return" after the "LIST" command to actually make the device send data?
Try sending "LIST\r", "LIST\n" or "LIST\r\n".
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