Serial Communication

[NewBiProgrammamer]

Hi all,

i have this code

include <stdio.h>

include <stdlib.h>

include <windows.h>

include <winbase.h>

int main()

{
OVERLAPPED osWrite = {0};
DCB PortDCB;
DWORD dwError,dwNumBytesWritten;
HANDLE hComm;
COMMTIMEOUTS CommTimeouts;

char porta="COM1:\0";
char pippo='5';
char c={"s1\0"};

hComm = CreateFile( porta,
GENERIC_READ | GENERIC_WRITE,
0,
0,
OPEN_EXISTING,
FILE_FLAG_OVERLAPPED,
0);
if (hComm == INVALID_HANDLE_VALUE)
{}// error opening port; abort

PortDCB.DCBlength = sizeof (DCB);

GetCommState(hComm,&PortDCB);

// Change the DCB structure settings.
PortDCB.BaudRate = 9600; // Current baud
PortDCB.fBinary = FALSE; // Binary mode; no EOF check
PortDCB.fParity = FALSE; // Enable parity checking
PortDCB.fOutxCtsFlow = FALSE; // No CTS output flow control
PortDCB.fOutxDsrFlow = FALSE; // No DSR output flow control
PortDCB.fDtrControl = DTR_CONTROL_ENABLE;
// DTR flow control type
PortDCB.fDsrSensitivity = FALSE; // DSR sensitivity
PortDCB.fTXContinueOnXoff = TRUE; // XOFF continues Tx
PortDCB.fOutX = FALSE; // No XON/XOFF out flow control
PortDCB.fInX = FALSE; // No XON/XOFF in flow control
PortDCB.fErrorChar = FALSE; // Disable error replacement
PortDCB.fNull = FALSE; // Disable null stripping
PortDCB.fRtsControl = RTS_CONTROL_ENABLE;
// RTS flow control
PortDCB.fAbortOnError = FALSE; // Do not abort reads/writes on
// error
PortDCB.ByteSize = 8; // Number of bits/byte, 4-8
PortDCB.Parity = NOPARITY; // 0-4=no,odd,even,mark,space
PortDCB.StopBits = ONESTOPBIT; // 0,1,2 = 1, 1.5, 2

if(!SetCommState(hComm,&PortDCB))
perror("");

GetCommTimeouts (hComm, &CommTimeouts);
// Change the COMMTIMEOUTS structure settings.
CommTimeouts.ReadIntervalTimeout = 10;
CommTimeouts.ReadTotalTimeoutMultiplier = 0;
CommTimeouts.ReadTotalTimeoutConstant = 0;
CommTimeouts.WriteTotalTimeoutMultiplier = 10;
CommTimeouts.WriteTotalTimeoutConstant = 1000;

if(!SetCommState(hComm,&PortDCB))
perror("");
if (!SetCommTimeouts (hComm, &CommTimeouts))
perror("");

TransmitCommChar(hComm,pippo);

WriteFile (hComm, // Port handle
c, // Pointer to the data to write
1, // Number of bytes to write
&dwNumBytesWritten, // Pointer to the number of bytes
// written
&osWrite // Must be NULL for Windows CE
);

return 0;
}

So the TransmitCommChar(hComm,pippo) work fine, in fact i can see the bits to the oscilloscope...but the WriteFile doesn't write anything!!!!

Someone could help me please?

Thanks a lot!

Regards

[Nobody/Anonymous]

Ooops. No you can't, this is all you can do in C:

fprintf(stdaux, "Give it to me baby"); -- will go to the Serial port(COM1:)
fprintf(stdprn, "Give it to me baby"); -- will go to the Printer(LPT1:)

You should still check with GetLastError though. Did you check the dwNumBytesWritten?

[Anonymous]

... You were right the first time, you simply open the necessary port:

port = fopen( "com1", wb+ ) ;
fprintf( port, "No, get it yourself\n");

However, this is more restrictive that using the Win32 API. See also: https://sourceforge.net/forum/message.php?msg_id=3996248

Clifford

[Nobody/Anonymous]

Are you checkin the return value from WriteFile?

If the function fails, the return value is zero. To get extended error information, call GetLastError.

Have you considered using fopen/fwrite/fclose?

[NewBiProgrammamer]

...oh is it possible to manage the serial port with fopen, fwrite etc?