I'm coding in visual studio. i have a problem in ConfigureSerialPort function.
#include <windows.h>
#include <stdio.h>
#include <string.h>
HANDLE hPort;
BOOL WriteByte(BYTE bybyte)
{
DWORD iBytesWritten=0;
DWORD iBytesToRead = 1;
if(WriteFile(hPort,(LPCVOID)
&bybyte,iBytesToRead,&iBytesWritten,NULL)==0)
return FALSE;
else return TRUE;
}
BOOL WriteString(const void *instring, int length)
{
int index;
BYTE *inbyte = (BYTE *) instring;
for(index = 0; index< length; ++index)
{
if (WriteByte(inbyte[index]) == FALSE)
return FALSE;
}
return TRUE;
}
BOOL ReadByte(BYTE &resp)
{
BOOL bReturn = TRUE;
BYTE rx;
DWORD dwBytesTransferred=0;
if (ReadFile (hPort, &rx, 1, &dwBytesTransferred, 0)> 0)
{
if (dwBytesTransferred == 1)
{
resp=rx;
bReturn = TRUE;
}
else bReturn = FALSE;
}
else bReturn = FALSE;
return bReturn;
}
BOOL ReadString(void *outstring, int *length)
{
BYTE data;
BYTE dataout[4096]={0};
int index = 0;
while(ReadByte(data)== TRUE)
{
dataout[index++] = data;
}
memcpy(outstring, dataout, index);
*length = index;
return TRUE;
}
void ClosePort()
{
CloseHandle(hPort);
return;
}
HANDLE ConfigureSerialPort(LPCSTR lpszPortName)
{
HANDLE hComm = NULL;
DWORD dwError;
DCB PortDCB;
COMMTIMEOUTS CommTimeouts;
// Open the serial port.
hComm = CreateFile (lpszPortName, // Pointer to the name of the port
GENERIC_READ | GENERIC_WRITE,
// Access (read-write) mode
0, // Share mode
NULL, // Pointer to the security attribute
OPEN_EXISTING, // How to open the serial port
0, // Port attributes
NULL); // Handle to port with attribute to copy
// Initialize the DCBlength member.
PortDCB.DCBlength = sizeof (DCB);
// Get the default port setting information.
GetCommState (hComm, &PortDCB);
// Change the DCB structure settings.
PortDCB.BaudRate = 9600; // Current baud
PortDCB.fBinary = TRUE; // Binary mode; no EOF check
PortDCB.fParity = TRUE; // 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
// Configure the port according to the specifications of the DCB structure.
if (!SetCommState (hComm, &PortDCB))
{
printf("Could not configure serial port\n");
return NULL;
}
// Retrieve the time-out parameters for all read and write operations
// on the port.
GetCommTimeouts (hComm, &CommTimeouts);
// Change the COMMTIMEOUTS structure settings.
CommTimeouts.ReadIntervalTimeout = MAXDWORD;
CommTimeouts.ReadTotalTimeoutMultiplier = 0;
CommTimeouts.ReadTotalTimeoutConstant = 0;
CommTimeouts.WriteTotalTimeoutMultiplier = 0;
CommTimeouts.WriteTotalTimeoutConstant = 0;
if (!SetCommTimeouts (hComm, &CommTimeouts))
{
printf("Could not set timeouts\n");
return NULL;
}
return hComm;
}
int main(void)
{
// Can also use COM2, COM3 or COM4 here
hPort = ConfigureSerialPort("COM1");
if(hPort == NULL)
{
printf("Com port configuration failed\n");
return -1;
}
// Call your ReadString and WriteString functions here
ClosePort();
return 0;
}
