help with serial port programming

[ShawnCoutts]

Hey guys

Ive been recently assigned a new task that requires me to be able to open, read, and write to a serial port. Ive been googling this for about 2 hours now, and as of yet have come up with nothing. I am using turbo C++ explorer, as my IDE.
Supposedly serial IO is just like File IO, but thats of no use to me, until I can open the serial port. Has anyone the knowledge of how to do this?

Shawn

 

[Totte]

I have done that. It's as simple as opening a file with the name "COM1" (or "COM2"...).

char Text[10];
// Check out COM1 - COM8 if they are available
for(int Counter = 1;Counter <= 8;Counter++)
{
sprintf(Text,"COM%u",Counter);
Handle = CreateFile(Text,GENERIC_READ | GENERIC_WRITE,0,0,OPEN_EXISTING,0,0);
if(Handle != INVALID_HANDLE_VALUE)
{
COMM_Select->Items->Add(Text); // Into the selector box
PurgeComm(Comm_Handle,PURGE_RXABORT); // Flush everything
CloseHandle(Handle); // Done, thank you
Available++; // The number of availables
}
else
{
if(GetLastError() == 5) // Existing but used by other
{
COMM_Select->Items->Add(Text);
Available++;
}
}
}


Totte
Keep making it perfect and it will end up broken.

 

[ShawnCoutts]

thanks a lot. This is very helpful and should allow me to start working on my project now.

Shawn

 

[BuilderSpec]

Hi

I wrote an application to read / write data from a handheld terminal that communicated via RS232 port. My code is now very specialized within the app but essentially my starting block was this :

void __fastcall TForm1::Button1Click(TObject *Sender)
{
HANDLE hCom = CreateFile("COM1",
GENERIC_READ | GENERIC_WRITE,
0,
NULL,
OPEN_EXISTING,
0,
NULL );

if(hCom)
{

DCB dcb;
ZeroMemory(&dcb, sizeof(dcb));
dcb.DCBlength = sizeof(dcb);

dcb.BaudRate = 57600;
dcb.ByteSize = 8;
dcb.Parity = NOPARITY; // NOPARITY and friends are
dcb.StopBits = ONESTOPBIT; // #defined in windows.h

// Set the port properties and write the string out the port.
if(SetCommState(hCom,&dcb))
{
DWORD ByteCount;
const char *msg = "Hello world!";
WriteFile(hCom,msg, strlen(msg),&ByteCount,NULL);
}
CloseHandle(hCom);
}
}


Again you need to use threads to do the actual reading and writing to the port.



Hope this helps!

Regards

BuilderSpec

 

[ShawnCoutts]

thanks for the help. It seems to work quite well.

Shawn