VC串口通讯

Question

请教个问题，
在MFC中利用API读写线程往串口发送和接收数据都没有问题。
但现在有个功能是想通过接收来的数据自动回复不同的数据，没想到好的办法实现，如自动收到0x81 发送01
                                                                            自动收到0X82 发送02 
                                                                            
写线程ThreadProcWrite函数中的WriteFile函数往串口中写书，我利用按钮来控制可以一个个的发，但是如上自动通过接收的发送却没想到好的办法？

Answer 1

BOOL CSerial::Open( int nPort, int nBaud )
{
if( m_bOpened ) return( TRUE );char szPort[15];
DCB dcb;wsprintf( szPort, "COM%d", nPort );
m_hComDev = CreateFile( szPort, GENERIC_READ | GENERIC_WRITE, 0, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL | FILE_FLAG_OVERLAPPED, NULL );
if( m_hComDev == 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_hComDev, &CommTimeOuts );m_OverlappedRead.hEvent = CreateEvent( NULL, TRUE, FALSE, NULL );
m_OverlappedWrite.hEvent = CreateEvent( NULL, TRUE, FALSE, NULL );dcb.DCBlength = sizeof( DCB );
GetCommState( m_hComDev, &dcb );
dcb.BaudRate = nBaud;
dcb.ByteSize = 8;
if( !SetCommState( m_hComDev, &dcb ) ||
!SetupComm( m_hComDev, 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_hComDev );
return FALSE;
}m_bOpened = TRUE;return m_bOpened;}int CSerial::InBufferCount( void )
{if( !m_bOpened || m_hComDev == NULL ) return( 0 );DWORD dwErrorFlags;
COMSTAT ComStat;ClearCommError( m_hIDComDev, &dwErrorFlags, &ComStat );return (int)ComStat.cbInQue;}DWORD CSerial::ReadData( void *buffer, DWORD dwBytesRead)
{if( !m_bOpened || m_hComDev == NULL ) return 0;BOOL bReadStatus;
DWORD dwErrorFlags;
COMSTAT ComStat;ClearCommError( m_hComDev, &dwErrorFlags, &ComStat );
if( !ComStat.cbInQue ) return 0;dwBytesRead = min(dwBytesRead,(DWORD) ComStat.cbInQue);bReadStatus = ReadFile( m_hComDev, buffer, dwBytesRead, &dwBytesRead, &m_OverlappedRead );
if( !bReadStatus ){
if( GetLastError() == ERROR_IO_PENDING ){
WaitForSingleObject( m_OverlappedRead.hEvent, 2000 );
return dwBytesRead;
}
return 0;
}return dwBytesRead;}DWORD CSerial::SendData( const char *buffer, DWORD dwBytesWritten)
{if( !m_bOpened || m_hComDev == NULL ) return( 0 );BOOL bWriteStat;bWriteStat = WriteFile( m_hComDev, buffer, dwBytesWritten, &dwBytesWritten, &m_OverlappedWrite );
if( !bWriteStat){
if ( GetLastError() == ERROR_IO_PENDING ) {
WaitForSingleObject( m_OverlappedWrite.hEvent, 1000 );
return dwBytesWritten;
}
return 0;
}
return dwBytesWritten;}

Answer 2

// 创建一个线程
DWORD param;
hThread = CreateThread((LPSECURITY_ATTRIBUTES)NULL, //安全属性
                    0,                          //初始化线程栈的大小，缺省为与主线程大小相同
(LPTHREAD_START_ROUTINE)ThreadFunction,  //线程的全局函数
                        &param,                     //此处传入了主框架的句柄 
0,                          //创建后立即激活
&dwThreadID);               //保存新线程的id
DWORD ThreadFunction(LPVOID pParam)  //线程函数
{
DWORD  dwEvtMask ,dwResult;
//  tOverLaped.Internal=0;   
//  tOverLaped.InternalHigh=0;   
  tOverLaped.Offset=0;   
  tOverLaped.OffsetHigh=0; 
tOverLaped.hEvent = CreateEvent(NULL, TRUE, FALSE, NULL);//创建一个事件
while(b_IsFun)
{
//等待窗口事件
WaitCommEvent(((CMSGCOMDlg*)AfxGetMainWnd())->hCom,
&dwEvtMask, &tOverLaped);
//如果事件没有信号,延时0.1秒
dwResult = WaitForSingleObject(tOverLaped.hEvent, 100);

if(dwResult == WAIT_OBJECT_0) //事件对象有信号
{
if(dwEvtMask == EV_RXCHAR) //接收到数据
{

::PostMessage(AfxGetMainWnd()->m_hWnd, CM_RECEIVE,
0,(LPARAM)EV_RXCHAR);
}
}
}
return 0;
}void CMSGCOMDlg::OnRecieveData(WPARAM wParam, LPARAM lParam) //如果串口有数据接收，调用这个函数
{
DWORD res, factbyte;
memset(DataBuffer, 0 ,1024);  //初始化数据缓冲区 
COMSTAT rst;
ClearCommError(hCom, &res, &rst); //清空串口错误标志,记录当前通信状态//  rOverLaped.Internal=0;   
//  rOverLaped.InternalHigh=0;   
rOverLaped.Offset=0;   
rOverLaped.OffsetHigh=0;
rOverLaped.hEvent = CreateEvent(NULL, TRUE, FALSE, NULL); //创建一个事件对象

if (ReadFile(hCom, DataBuffer, (DWORD)rst.cbInQue, &factbyte, &rOverLaped)) //读取数据到缓冲区中
DataBuffer[rst.cbInQue] = 0;
else
{
//GetLastError()函数返回ERROR_IO_PENDING,表明串口正在进行读操作
if(GetLastError()==ERROR_IO_PENDING)
res = WaitForSingleObject(rOverLaped.hEvent, 2000);
}
        // 在这里添加代码判断DataBuffer接收到的数据是什么，若0x81 发送01 若0X82 发送02 }