serial port communication using c++

sir,
i have been asked to do serial port programming using C++

it should include opening port, close and view the status of the serial port. You should also be able to control speed, timeout,start bit,stop bit,parity bit and stuff like that

please provide me some solution in the form of sample programs,books or techniques..
since i am new to programming,i dont know from where and how should i start

regards,
mayuri

Well it all depends on which Operating system and compiler you're using.

see i am using win CE
and microsoft visual studio
pls provide a solution instead of making things difficult

Mayuri_608,

I opened the free copy Visual C++ that Microsoft allowed me to download as part of their Express line of products. Then I went to the help menu, and I selected the Microsoft Developer Network (MSDN) Forums. I ran a search for "serial port ioctl," and this is the resulting page: serial port ioctl - MSDN Search.

Due to personal goals, I genuinely prefer to do low level i/o in Linux when I can, but I have done some work with the Microsoft facilities...their documentation is often more complete and support is a lot more standard than Linux once was. Check out the search results, I think that Windows CE came up second or third in the results too. I don't mean to be difficult, but last time I checked the board was more like "...show and tell..." rather than "...would you like fries with that...." I would be delighted to work through your attempts with you.

Best Regards,

Code:

---


// serial.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"


int _tmain(int argc, _TCHAR* argv[])
{
        return 0;
}


#undef UNICODE
#include "stdafx.h"
#include <windows.h>



void PrintError( LPCSTR str)
{
LPVOID lpMessageBuffer;
int error = GetLastError();
FormatMessage(
FORMAT_MESSAGE_ALLOCATE_BUFFER |
FORMAT_MESSAGE_FROM_SYSTEM,
NULL,
error,
MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), //The user default language
(LPTSTR) &lpMessageBuffer,
0,
NULL
);
printf("%s: (%d) %s\n\n",str,error,lpMessageBuffer);
LocalFree( lpMessageBuffer );
}

int main(int argc, char* argv[])
{
// open port for I/O
HANDLE h = CreateFile(argv[1],
GENERIC_READ|GENERIC_WRITE,
0,NULL,
OPEN_EXISTING,0,NULL);

if(h == INVALID_HANDLE_VALUE) {
PrintError("E012_Failed to open port");
} else {
// set timeouts
COMMTIMEOUTS cto = { 1, 100, 1000, 0, 0 };
DCB dcb;
if(!SetCommTimeouts(h,&cto))
PrintError("E013_SetCommTimeouts failed");

// set DCB
memset(&dcb,0,sizeof(dcb));
dcb.DCBlength = sizeof(dcb);
dcb.BaudRate = 19200;
dcb.fBinary = 1;
dcb.fDtrControl = DTR_CONTROL_ENABLE;
dcb.fRtsControl = RTS_CONTROL_ENABLE;
dcb.fOutxCtsFlow = 1;
dcb.fRtsControl = DTR_CONTROL_HANDSHAKE;

dcb.Parity = NOPARITY;
dcb.StopBits = ONESTOPBIT;
dcb.ByteSize = 8;

if(!SetCommState(h,&dcb))
PrintError("E014_SetCommState failed");


char buf[7];
DWORD read = 0;
DWORD write=1; // Number of bytes to write to serial port
buf[0] = 72; // Decmial value to write to serial port
WriteFile(h,buf,write,&write,NULL); // write is updated with the number of bytes written

ReadFile(h,buf,sizeof(buf),&read,NULL); // read is updated with the number of bytes read
DWORD i;
for (i=0; i<read; i++)
printf("%i ", (unsigned char)buf[i]);

CloseHandle(h);
}

return 0;
}

---

hey dis is d program for serial port communication..i was able to compile it but i hav a problem wid o/p
i am getting this error after compilation
E012_Failed to open port: <5> Access is denied.

i have connected serial port also to the pc and set all d parameters in COM1
pls resolve my query..
regards,
mayuri

what are you passing as argv[1] to your program?

Quote:

---

Originally Posted by vart

what are you passing as argv[1] to your program?

---

i m passng COM1 as argument..i m doong dat in project properties
- Configuration Properties - Debugging - Command Arguments, in Visual Studio

is it correct?
if not den pls provide some solution instead of teasing me

Quote:

---

Originally Posted by mayuri_608

i m passng COM1 as argument..

---

should be ok

but I would start with hardcoded value
as in the sample Configuring a Communications Resource (Windows)

to see if problem is in passing arguments to program or CreateFile itself


have you use HyperTerminal to see if the port could be opened properly before using your program?