有关串口问题，在线等...

Question

为什么我在调试用API写的串口通信程序时，以文本形式发送能接收到，文本不能显示的接收不到呢？
例如：0x34能接收到，而0x11就接收不到。

Answer 1

我是调试时收到数据长度为0
代码如下：void CMySerialComDlg::OnTimer(UINT nIDEvent) 
{
// TODO: Add your message handler code here and/or call default
int Len;
char buffer[1024];
//buffer[Len]='\0';
Len=::ReadCommBlock(m_ComConfig,buffer,1024);
//buffer[Len]='\0';
if(Len!=0)
{
buffer[Len]='\0';
m_receive+=buffer;
  UpdateData(FALSE);
}
CDialog::OnTimer(nIDEvent);
}
int ReadCommBlock(CComStatus& comDev,LPSTR lpszBlock, int nMaxLength )
{
   BOOL       fReadStat ;   COMSTAT    ComStat ;
   DWORD      dwErrorFlags;
   DWORD      dwLength;
   DWORD      dwError;
   char       szError[ 10 ] ;   // only try to read number of bytes in queue
   ClearCommError( comDev.m_hCom, &dwErrorFlags, &ComStat ) ;
   dwLength = min( (DWORD) nMaxLength, ComStat.cbInQue ) ;   if (dwLength > 0)
   {
      fReadStat = ReadFile( comDev.m_hCom, lpszBlock,
                    dwLength, &dwLength, &(comDev.m_rdos) ) ;
  if(dwLength!=0)
  dwLength=32;
      if (!fReadStat)
      {
         if (GetLastError() == ERROR_IO_PENDING)
         {
            OutputDebugString("\n\rIO Pending");
            // We have to wait for read to complete.
            // This function will timeout according to the
            // CommTimeOuts.ReadTotalTimeoutConstant variable
            // Every time it times out, check for port errors
            while(!GetOverlappedResult( comDev.m_hCom ,
               &(comDev.m_rdos), &dwLength, TRUE ))
            {
               dwError = GetLastError();
               if(dwError == ERROR_IO_INCOMPLETE)
                  // normal result if not finished
                  continue;
               else
               {
                  // an error occurred, try to recover
                  wsprintf( szError, "<CE-%u>", dwError ) ;
                  ClearCommError( comDev.m_hCom , &dwErrorFlags, &ComStat ) ;
                  break;
               }            }       }
         else
         {
            // some other error occurred
            dwLength = 0 ;
            ClearCommError( comDev.m_hCom , &dwErrorFlags, &ComStat ) ;
         }
      }
   }   return ( dwLength ) ;}