serial.cpp

一个与串行GPS通信的应用程序源码

// Serial.cpp

#include "stdafx.h"
#include "Serial.h"
#include "rs485.h"

CSerial::CSerial()
{

	memset( &m_OverlappedRead, 0, sizeof( OVERLAPPED ) );
 	memset( &m_OverlappedWrite, 0, sizeof( OVERLAPPED ) );
	m_hIDComDev = NULL;
	m_bOpened = FALSE;

}

CSerial::~CSerial()
{

	Close();

}

BOOL CSerial::Open( int nPort, int nBaud )
{

	if( m_bOpened ) 
	{
		return( TRUE );
	}
	char szPort[15];
	char szComParams[50];
	DCB dcb;

	wsprintf( szPort, "COM%d", nPort );
	m_hIDComDev = CreateFile( szPort, GENERIC_READ | GENERIC_WRITE, 0, 
		NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL | FILE_FLAG_OVERLAPPED, NULL );
	if( m_hIDComDev == NULL ) 
	{
	
		return( FALSE );
	}
	memset( &m_OverlappedRead, 0, sizeof( OVERLAPPED ) );
 	memset( &m_OverlappedWrite, 0, sizeof( OVERLAPPED ) );

	COMMTIMEOUTS CommTimeOuts;

	CommTimeOuts.ReadIntervalTimeout = 0xFFFFFFFF;
	CommTimeOuts.ReadTotalTimeoutMultiplier = 0;
	CommTimeOuts.ReadTotalTimeoutConstant = 0;
	CommTimeOuts.WriteTotalTimeoutMultiplier = 0;
	CommTimeOuts.WriteTotalTimeoutConstant = 5000;

	SetCommTimeouts( m_hIDComDev, &CommTimeOuts );

	wsprintf( szComParams, "COM%d:%d,n,8,1", nPort, nBaud );

	m_OverlappedRead.hEvent = CreateEvent( NULL, TRUE, FALSE, NULL );
	m_OverlappedWrite.hEvent = CreateEvent( NULL, TRUE, FALSE, NULL );

	dcb.DCBlength = sizeof( DCB );
	GetCommState( m_hIDComDev, &dcb );
	dcb.BaudRate = nBaud;
	dcb.ByteSize = DATABITS;//------------定义在RS485.H------------------
	dcb.StopBits = STOPBITS;//------------定义在RS485.H------------------

	unsigned char ucSet;
	ucSet = (unsigned char) ( ( FC_RTSCTS & FC_DTRDSR ) != 0 );
	ucSet = (unsigned char) ( ( FC_RTSCTS & FC_RTSCTS ) != 0 );
	ucSet = (unsigned char) ( ( FC_RTSCTS & FC_XONXOFF ) != 0 );

	if( !SetCommState( m_hIDComDev, &dcb ) ||
		!SetupComm( m_hIDComDev, 10000, 10000 ) ||
		m_OverlappedRead.hEvent == NULL ||
		m_OverlappedWrite.hEvent == NULL )
	{
		DWORD dwError = GetLastError();
		if( m_OverlappedRead.hEvent != NULL )  
			CloseHandle( m_OverlappedRead.hEvent );
		if( m_OverlappedWrite.hEvent != NULL ) 
		{
			CloseHandle( m_OverlappedWrite.hEvent );
		}
		CloseHandle( m_hIDComDev );
		return( FALSE );
	}

	 m_bOpened= TRUE;

//-------------调试用--------------------------------------
//	if ( m_bOpened )
//	{
//		AfxMessageBox("comm 1 open ok", MB_OK, 0);
//	}
//--------------------------------------------------------
	return( m_bOpened );

}

BOOL CSerial::Close( void )
{

	if( !m_bOpened || m_hIDComDev == NULL ) 
	{
		return( TRUE );
	}
	if( m_OverlappedRead.hEvent != NULL ) 
	{
		CloseHandle( m_OverlappedRead.hEvent );
	}
	if( m_OverlappedWrite.hEvent != NULL ) 
	{
		CloseHandle( m_OverlappedWrite.hEvent );
	}
	CloseHandle( m_hIDComDev );

	m_bOpened = FALSE;
	m_hIDComDev = NULL;

	return( TRUE );

}

BOOL CSerial::WriteCommByte( unsigned char ucByte )
{
	BOOL bWriteStat;
	DWORD dwBytesWritten;

	bWriteStat = WriteFile( m_hIDComDev, (LPSTR) &ucByte, 1, &dwBytesWritten,
		&m_OverlappedWrite );
	if( !bWriteStat && ( GetLastError() == ERROR_IO_PENDING ) )
	{
		if( WaitForSingleObject( m_OverlappedWrite.hEvent, 1000 ) ) 
		{
			dwBytesWritten = 0;
		}
		else
		{
			GetOverlappedResult( m_hIDComDev, &m_OverlappedWrite, &dwBytesWritten, FALSE );
			m_OverlappedWrite.Offset += dwBytesWritten;
		}
	}

	return( TRUE );

}

int CSerial::SendData( const char *buffer, int  size )
{

	if( !m_bOpened || m_hIDComDev == NULL ) 
	{
		return( 0 );
	}

	DWORD dwBytesWritten = 0;
	int i;
	for( i=0; i<size; i++ )
	{
		WriteCommByte( buffer[i] );
		dwBytesWritten++;
	}

	return( (int) dwBytesWritten );

}

int CSerial::ReadDataWaiting( void )
{

	if( !m_bOpened || m_hIDComDev == NULL ) 
	{
		return( 0 );
	}

	DWORD dwErrorFlags;
	COMSTAT ComStat;

	ClearCommError( m_hIDComDev, &dwErrorFlags, &ComStat );

	return( (int) ComStat.cbInQue );

}

int CSerial::ReadData( void *buffer, int limit )
{

	if( !m_bOpened || m_hIDComDev == NULL )
	{
		return( 0 );
	}

	BOOL bReadStatus;
	DWORD dwBytesRead, dwErrorFlags;
	COMSTAT ComStat;

	ClearCommError( m_hIDComDev, &dwErrorFlags, &ComStat );
	if( !ComStat.cbInQue ) 
	{
		return( 0 );
	}

	dwBytesRead = (DWORD) ComStat.cbInQue;
	if( limit < (int) dwBytesRead )
	{
		dwBytesRead = (DWORD) limit;
	}

	bReadStatus = ReadFile( m_hIDComDev, buffer, dwBytesRead, &dwBytesRead, &m_OverlappedRead );
	if( !bReadStatus )
	{
		if( GetLastError() == ERROR_IO_PENDING )
		{
			WaitForSingleObject( m_OverlappedRead.hEvent, 2000 );
			return( (int) dwBytesRead );
		}
		return( 0 );
	}

	return( (int) dwBytesRead );

}