commport.cpp

可以接收NMEA-0183格式的GPS数据自动化搜索本枸的GPS接口

	if(fp!=NULL)
	{
		fscanf(fp,"%s",ComName);
		fclose(fp);
	}
	else
		ComName="COM1:";

	int Baud=4800;

	SettingStatus=1;
	if(SettingStatus==1)
	{
		DWORD dwError;
		DCB PortDCB;
		COMMTIMEOUTS CommTimeouts;
		
		// Open the serial port.
		hPort = CreateFile (ComName, // 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

		// If it fails to open the port, return FALSE.
		if ( hPort == INVALID_HANDLE_VALUE ) 
		{
			// 不能打开串口，是否自动搜索
			CString msg=_T("不能打开GPS接口：");
			msg+=ComName;
			msg+=_T("!");
			msg+=_T("\n按是自动搜索GPS端口，按否放弃！");
			int flag=AfxMessageBox(msg,MB_YESNO);
			if(flag==IDNO)
			{
				flag=AfxMessageBox("没有连接GPS将不能导航！\n确定吗？",MB_YESNO);
				if(flag==IDNO)
				{
					CString portname=FindGPSPort();
					if(portname=="")
						AfxMessageBox("没有找到GPS设备！",MB_OK);
				}
			}
			else
			{
				CString portname=FindGPSPort();
				if(portname=="")
					AfxMessageBox("没有找到GPS设备！",MB_OK);
			}
		}
		else
		{
			int ComFlag=SetupComm(hPort,4096,4096);
			if(ComFlag==0)AfxMessageBox(_T("串口缓冲区设置错误！"),MB_OK);

			PortDCB.DCBlength = sizeof (DCB);     

			// Get the default port setting information.
			GetCommState (hPort, &PortDCB);

			// Change the DCB structure settings.
			PortDCB.BaudRate = Baud;              // 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 (hPort, &PortDCB))
			{
			  // Could not create the read thread.
			  AfxMessageBox (TEXT("配置串口错误！"));
			  dwError = GetLastError ();
			}

			// Retrieve the time-out parameters for all read and write operations
			// on the port. 
			GetCommTimeouts (hPort, &CommTimeouts);

			// Change the COMMTIMEOUTS structure settings.
			CommTimeouts.ReadIntervalTimeout = MAXDWORD;  
			CommTimeouts.ReadTotalTimeoutMultiplier = 0;  
			CommTimeouts.ReadTotalTimeoutConstant = 0;    
			CommTimeouts.WriteTotalTimeoutMultiplier = 10;  
			CommTimeouts.WriteTotalTimeoutConstant = 1000;    

			// Set the time-out parameters for all read and write operations
			// on the port. 
			if (!SetCommTimeouts (hPort, &CommTimeouts))
			{
			  // Could not create the read thread.
			  AfxMessageBox (TEXT("不能设置超时参数！")); 
			  dwError = GetLastError ();
			}

			// Direct the port to perform extended functions SETDTR and SETRTS
			// SETDTR: Sends the DTR (data-terminal-ready) signal.
			// SETRTS: Sends the RTS (request-to-send) signal. 
			EscapeCommFunction (hPort, SETDTR);
			EscapeCommFunction (hPort, SETRTS);	
			CString msg=_T("成功打开");
			msg+=ComName;
			msg+=_T("!");

			//unsigned char Info[19200];
			//DWORD dwBytesRead;

			//ReadFile(hPort,&Info,19200,&dwBytesRead,NULL);
			ClearCommBuf(2);
	

		}
	}
	return 1;
}
//////////////////////////////////////////////////////////////////////////
//功能：向串口写数据
//////////////////////////////////////////////////////////////////////////
void CCommPort::SendByte(HANDLE hPort, BYTE Byte)
{
	DWORD dwError,dwNumBytesWritten;

	if (!WriteFile (hPort,              // Port handle
					&Byte,              // Pointer to the data to write 
					1,                  // Number of bytes to write
					&dwNumBytesWritten, // Pointer to the number of bytes 
										// written
					NULL))              // Must be NULL for Windows CE
	{
	  // WriteFile failed. Report error.
	  dwError = GetLastError ();
	  AfxMessageBox(_T("写入一个字节错误！"),MB_OK);
	}

}

void CCommPort::ClosePort()
{
	DWORD dwError;
	
	if (hPort != INVALID_HANDLE_VALUE)
	{
	  // Close the communication port.
	  if (!CloseHandle (hPort))
	  {
		dwError = GetLastError ();
		AfxMessageBox(_T("关闭串口错误！"),MB_OK); 
	  }
	  else
	  {
		hPort = INVALID_HANDLE_VALUE;
		//AfxMessageBox(_T("成功关闭串口！"),MB_OK);
	  }
	}
}

void CCommPort::StartRead()
{
	if ( hPort == INVALID_HANDLE_VALUE ) 
	{
		AfxMessageBox(_T("没有打开串口！"),MB_OK);
		return;
	}
	//清空串口的缓存
	//unsigned char Info[19200];
	//DWORD dwBytesRead;
	//ReadFile(hPort,&Info,19200,&dwBytesRead,NULL);
	//清除读缓冲区
	ClearCommBuf(2);
}

void CCommPort::ShowSatPos()
{
}

///////////////////////////////////////////////////////////////////////
//功能：清空串口缓冲区
//history			name			data			remark
//					wanfangjie		2002.09.23		create
//参数说明	0，清读缓冲区，1，清写缓冲区
///////////////////////////////////////////////////////////////////////
void CCommPort::ClearCommBuf(int iType)
{
	switch(iType)
	{
	case 0:
		PurgeComm(hPort,PURGE_RXCLEAR);
		break;
	case 1:
		PurgeComm(hPort,PURGE_TXCLEAR);
		break;
	case 2:
		PurgeComm(hPort,PURGE_TXCLEAR|PURGE_RXCLEAR);
		break;
	default:
		PurgeComm(hPort,PURGE_TXCLEAR|PURGE_RXCLEAR);
	}

}

CString CCommPort::FindGPSPort()
{
	char tempstr[2];
	CString portname;
	int Baud=4800;
	for(int i=1;i<=8;i++)
	{
		portname="COM";
		itoa(i,tempstr,10);
		portname+=tempstr;
		portname+=":";


		DWORD dwError;
		DCB PortDCB;
		COMMTIMEOUTS CommTimeouts;
		
		// Open the serial port.
		hPort = CreateFile (portname, // 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

		// If it fails to open the port, return FALSE.
		if ( hPort == INVALID_HANDLE_VALUE ) 
		{
			portname="";
		}
		else
		{
			int ComFlag=SetupComm(hPort,4096,4096);
			if(ComFlag==0)AfxMessageBox(_T("串口缓冲区设置错误！"),MB_OK);

			PortDCB.DCBlength = sizeof (DCB);     

			// Get the default port setting information.
			GetCommState (hPort, &PortDCB);

			// Change the DCB structure settings.
			PortDCB.BaudRate = Baud;              // 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 

			if (!SetCommState (hPort, &PortDCB))
			{
			  AfxMessageBox (TEXT("配置串口错误！"));
			  dwError = GetLastError ();
			}

			GetCommTimeouts (hPort, &CommTimeouts);

			CommTimeouts.ReadIntervalTimeout = MAXDWORD;  
			CommTimeouts.ReadTotalTimeoutMultiplier = 0;  
			CommTimeouts.ReadTotalTimeoutConstant = 0;    
			CommTimeouts.WriteTotalTimeoutMultiplier = 10;  
			CommTimeouts.WriteTotalTimeoutConstant = 1000;    

			if (!SetCommTimeouts (hPort, &CommTimeouts))
			{
			  AfxMessageBox (TEXT("不能设置超时参数！")); 
			  dwError = GetLastError ();
			}

			EscapeCommFunction (hPort, SETDTR);
			EscapeCommFunction (hPort, SETRTS);	

			Sleep(1000);
			DWORD dwBytesRead;
			unsigned char Info[19200];
			ReadFile(hPort,&Info,19200,&dwBytesRead,NULL);
			for(int j=0;j<dwBytesRead;j++)
			{
				if(Info[j]=='$')
				{
					if(Info[j+1]=='G'&&Info[j+2]=='P'&&Info[j+3]=='G')//如果是GPS数据
					{
						FILE *fp;
						fp=fopen("gpsport.dat","w+");
						fprintf(fp,"%s",portname);
						fclose(fp);
						return portname;
					}
				}
			}
			portname="";
			ClearCommBuf(2);
			ClosePort();
		}
	}
	return portname;
}