关于串口通信的问题！

Question

我想从一个串口读取数据，改怎么办？

Answer 1

Serial Communications in Win32
在msdn里搜一下，主要是些文件读写操作，不是很难

Answer 2

用API
ZComm::open(char *szPort,int Baud_rate, BOOL overlapped)
{
    int retbuflength=0;
   

    if (overlapped) { //异步方式打开串口
memset( &READ_OS, 0, sizeof( OVERLAPPED ) ) ;    
        memset( &WRITE_OS, 0, sizeof( OVERLAPPED ) ) ;            READ_OS.hEvent = CreateEvent( NULL,    // no security
                                      TRUE,    // explicit reset req
                                     FALSE,   // initial event reset
                                      NULL ) ; // no name
        if (READ_OS.hEvent == NULL)   return  -1  ;
       
        WRITE_OS.hEvent = CreateEvent( NULL,    // no security
                                      TRUE,    // explicit reset req
                                     FALSE,   // initial event reset
                                      NULL ) ; // no name
        if (NULL == WRITE_OS.hEvent)
        {
           CloseHandle( READ_OS.hEvent ) ;
           return -1  ;
        }
       
    idComDev=CreateFile( szPort, GENERIC_READ | GENERIC_WRITE,
                  0,                    // exclusive access
                  NULL,                 // no security attrs
                  OPEN_EXISTING,
                  FILE_ATTRIBUTE_NORMAL|
  FILE_FLAG_OVERLAPPED, // overlapped I/O
                  NULL );
   
    olap=TRUE;
} //同步方式打开串口
else   idComDev=CreateFile( szPort, GENERIC_READ | GENERIC_WRITE,
                  0,                    // exclusive access
                  NULL,                 // no security attrs
                  OPEN_EXISTING,
                  0,  //is overlapped or no
                  NULL );
   
   if (idComDev==(HANDLE) -1){
      
  DWORD RR=GetLastError();
  CloseHandle(idComDev) ;
      if (olap){
         CloseHandle( READ_OS.hEvent ) ;
     CloseHandle( WRITE_OS.hEvent ) ;
      }
      fCOMMOpened=0; 
      olap=FALSE;
      return (0);
   }
   
   set_baudrate(Baud_rate);
   fCOMMOpened=1;
   SetupComm(idComDev,11520,2048);
   PurgeComm(idComDev, PURGE_TXABORT | PURGE_RXABORT |
                           PURGE_TXCLEAR | PURGE_RXCLEAR ) ;
   SetCommMask(idComDev, EV_RXFLAG );
   //set time out 
   SetTimeOut(10,50,200);
   return (1);
}BOOL ZComm::SetTimeOut(DWORD ReadIntervalTimeout,
               DWORD ReadTotalTimeoutMultiplier,
   DWORD ReadTotalTimeoutConstant)
{  
   COMMTIMEOUTS timeouts;   GetCommTimeouts(idComDev,&timeouts);
   timeouts.ReadIntervalTimeout=ReadIntervalTimeout;
   timeouts.ReadTotalTimeoutMultiplier=ReadTotalTimeoutMultiplier;
   timeouts.ReadTotalTimeoutConstant=ReadTotalTimeoutConstant;
   return SetCommTimeouts(idComDev,&timeouts);
}ZComm::Close()
{
  if (fCOMMOpened==1) {
      fCOMMOpened=0; 
      CloseHandle(idComDev) ;
  olap=FALSE;
  if (olap){
      CloseHandle( READ_OS.hEvent ) ;
      CloseHandle( WRITE_OS.hEvent ) ;
      }
  return 1;
  }
  return 0; 
}int ZComm::set_baudrate(int baud_rate)
{  
   DCB  dcb;
   BOOL fsuccess;
   
   fsuccess = GetCommState(idComDev, &dcb);
   if (!fsuccess) return 0;
   
   dcb.BaudRate =baud_rate;
   dcb.ByteSize =8; //number of bits/byte, 4-8 
   dcb.Parity =NOPARITY;
   dcb.StopBits =ONESTOPBIT;
   dcb.EvtChar=0x02;
   /*
   dcb.fOutxCtsFlow = 1;
   dcb.fDtrControl = 1;
   dcb.fRtsControl = 2;
   dcb.EofChar = 0;
   */
   dcb.fOutxCtsFlow = 0;
   dcb.fDtrControl = 0;
   dcb.fRtsControl = 2;
   dcb.EofChar = 26;
   //dcb.fNull=TRUE;   fsuccess=SetCommState(idComDev, &dcb);
   if (!fsuccess) return 0;   return 1;
}// USE BY READSTREAM()
//
DWORD ZComm::ReadByte(BYTE * buf)
{
      OVERLAPPED  os; 
  BOOL        fReadStat;
  DWORD       dwEvtMask;
  DWORD       dwErrorFlags;
  COMSTAT     ComStat;
  DWORD       dwLength;   if (fCOMMOpened==0) return 0; //串口未打开   if (olap) // OVERLAPPED 
  { 
         SetCommMask(idComDev, EV_RXCHAR );
 memset( &os, 0, sizeof( OVERLAPPED ));
 os.hEvent = CreateEvent( NULL,    // no security
                                  TRUE,    // explicit reset req
                                  FALSE,   // initial event nonsignaled. 
                                  NULL ) ; // no name
         if (os.hEvent == NULL)  {
            OutputDebugString("\n\r Failed to create event for ReadByte");
        CloseHandle(os.hEvent);
return 0;
 }
 
 dwEvtMask = 0 ;
 WaitCommEvent(idComDev,&dwEvtMask,&os);
   
 if (WaitForSingleObject(os.hEvent,MAXTIMEOUT)==WAIT_TIMEOUT)
 {
 OutputDebugString("\n\r time out for ReadByte");
 CloseHandle(os.hEvent);
 return 0;
 } 
 
 if ((dwEvtMask & EV_RXCHAR) == EV_RXCHAR) 
 {
ClearCommError(idComDev, &dwErrorFlags, &ComStat);
        dwLength = max(1,ComStat.cbInQue);
//dwLength=1;
  fReadStat = ReadFile( idComDev,buf,dwLength,&dwLength, &READ_OS);
    if (!fReadStat)
{
  OutputDebugString("\n\r can not Read Byte");
  CloseHandle(os.hEvent);
return 0;
            }
else{
CloseHandle(os.hEvent);
return dwLength; 
}
   }
 else{
 CloseHandle(os.hEvent);
 return 0; 
 }
  }
  else{ //NOT OVERLAPPED
   dwLength=0; 
      ReadFile(idComDev,buf,1,&dwLength, &READ_OS);
   return dwLength;
  }
}