关于串口的问题

Question

  HANDLE m_hCom;
  BOOL  InitilizeCom()//初始化串口
 {
         m_hCom = CreateFile( "COM2", GENERIC_READ | GENERIC_WRITE, 0, 
NULL, OPEN_EXISTING, ILE_ATTRIBUTE_NORMAL, NULL );
if ( INVALID_HANDLE_VALUE==m_hCom )
{
              return FALSE;
}
SetupComm( m_hCom, 2048, 2048 ); DCB dcb;
GetCommState( m_hCom, &dcb );
dcb.BaudRate = 9600;
dcb.ByteSize = 8;
dcb.StopBits = ONESTOPBIT;
dcb.Parity = NOPARITY; if ( !SetCommState( m_hCom, &dcb ) )
{
CloseHandle( m_hCom );
                  return false;
}
    PurgeComm( m_hCom, PURGE_TXABORT | PURGE_RXABORT |
                                      PURGE_TXCLEAR | PURGE_RXCLEAR ) ;    COMMTIMEOUTS CommTimeOuts;
    CommTimeOuts.ReadIntervalTimeout = 0xFFFFFFFF ;
    CommTimeOuts.ReadTotalTimeoutMultiplier = 0 ;
    CommTimeOuts.ReadTotalTimeoutConstant = 0 ;
    CommTimeOuts.WriteTotalTimeoutMultiplier = 1;
    CommTimeOuts.WriteTotalTimeoutConstant = 0 ;
    SetCommTimeouts( m_hCom, &CommTimeOuts ) ;
     return true;
     
     }
    
    BOOL SendDataToCom(char* buf)//把要发送的数据放到buf中
   {
         ULONG uByteOfSend = 0;
         int uSend = strlen(buf);
         if( !WriteFile(m_hCom, buf, uSend, &uByteOfSend, NULL) )
{
return FALSE;
}
      return true;
    }首先初始化串口，设置波特率，停止位，数据位，校验位。

Answer 1

HANDLE CreateFile(    LPCTSTR lpFileName, // pointer to name of the file 
    DWORD dwDesiredAccess, // access (read-write) mode 
    DWORD dwShareMode, // share mode 
    LPSECURITY_ATTRIBUTES lpSecurityAttributes, // pointer to security attributes 
    DWORD dwCreationDistribution, // how to create 
    DWORD dwFlagsAndAttributes, // file attributes 
    HANDLE hTemplateFile // handle to file with attributes to copy  
  );#include <vcl.h>
#pragma hdrstop#include "Unit1.h"
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
TForm1 *Form1;
// Define may be used at same time,
// extern TForm2 *Form2;
HANDLE hcom;
HANDLE xModemThreadHandle;
DWORD  idxModemThread;
// Define one extern thread and used serier port,
// extern void xModemThread();
//---------------------------------------------------------------------------
bool __fastcall TForm1::InitPort(AnsiString PortName)
{
_DCB        myDCB;
COMMTIMEOUTS  myTMO;
bool  Result;  // simply define communication handle,if existing and closing
  // renew to create,
  if(hcom != 0/*INVALID_HANDLE_VALUE*/)
    CloseHandle(hcom);  //create communication handle,
  hcom=CreateFile(PortName.c_str(), // port name
                GENERIC_READ&brvbar;GENERIC_WRITE,  // RW access mode
                  0, // exclusive mode
                  NULL, // no security attributes
                  OPEN_EXISTING, // open existing port
                  0, // not overlapped
                  0);
  Result = (hcom!=INVALID_HANDLE_VALUE);
  if(!Result)
      MessageDlg("not open port:"+PortName,
                  mtConfirmation,TMsgDlgButtons()<<mbYes<<mbNo,0);
  else
    {
    //set communlcation mask,set of events to be monitored,
    if(!SetCommMask(hcom,EV_RXFLAG))
      {
      if(MessageDlg("not set mask:"+PortName,
                  mtConfirmation,TMsgDlgButtons()<<mbYes<<mbNo,0)!= mrYes)
      {
      CloseHandle(hcom);
      Result=false;
      exit(1);
      }
      else{
      CloseHandle(hcom);
      Result=true;
      exit(1);
      }
      }
    //initializes the communications parameters,
    if(!SetupComm(hcom,4096,4096))//4096 is specifies send and recvieve size,
      {
      if(MessageDlg("not setup communiation:"+PortName,
                  mtConfirmation,TMsgDlgButtons()<<mbYes<<mbNo,0)!= mrYes)
      {
      CloseHandle(hcom);
      Result=false;
      exit(1);
      }
      else{
      CloseHandle(hcom);
      Result=true;
      exit(1);
      }
      }
    //get the communications state and DCB struct,
    if(!GetCommState(hcom,&myDCB))
      {
      if(MessageDlg("not get state:"+PortName,
                  mtConfirmation,TMsgDlgButtons()<<mbYes<<mbNo,0)!= mrYes)
      {
      CloseHandle(hcom);
      Result=false;
      exit(1);
      }
      else{
      CloseHandle(hcom);
      Result=true;
      exit(1);
      }
      }
    //set dcb state,include baudrate/bytebit/stopbit/parity,
    myDCB = GetDCBParater(myDCB);
    // if(!BuildCommDCB("COM1:baud=1200 parity=N data=8 stop=1",&myDCB));
    // { 以上个的函数用法同下 }
    if(!SetCommState(hcom,&myDCB))
      {
      //unsigned long TTT = GetLastError();
      if(MessageDlg("not set state:"+PortName,
                  mtConfirmation,TMsgDlgButtons()<<mbYes<<mbNo,0)!=mrYes)
      {
      CloseHandle(hcom);
      Result=false;
      exit(1);
      }
      else{
      CloseHandle(hcom);
      Result=true;
      exit(1);
      }
      }
    if(!GetCommTimeouts(hcom,&myTMO))
      {
      if(MessageDlg("not get out time:"+PortName,
                  mtConfirmation,TMsgDlgButtons()<<mbYes<<mbNo,0)!= mrYes)
      {
      CloseHandle(hcom);
      Result=false;
      exit(1);
      }
      else{
      CloseHandle(hcom);
      Result=true;
      exit(1);
      }
      }
    //set out time function and coeff.
      myTMO.ReadIntervalTimeout = MAXDWORD;
      myTMO.ReadTotalTimeoutMultiplier = 0;
      myTMO.ReadTotalTimeoutConstant = 0;
      myTMO.WriteTotalTimeoutMultiplier =0;
      myTMO.WriteTotalTimeoutConstant =1000;
    if(!SetCommTimeouts(hcom,&myTMO))
      {
      if(MessageDlg("not set out time:"+PortName,
                  mtConfirmation,TMsgDlgButtons()<<mbYes<<mbNo,0)!=mrYes)
      {
      CloseHandle(hcom);
      Result=false;
      exit(1);
      }
      else{
      CloseHandle(hcom);
      Result=true;
      exit(1);
      }
      }
  //API_Function: clear send buffer,
    PurgeComm(hcom,PURGE_TXCLEAR);
  //API-Function: clear recvive buffer,
    PurgeComm(hcom,PURGE_RXCLEAR);
    }
  return Result;
}bool __fastcall TForm1::RecvData()
{
  bool Result;
  AnsiString ReadStr;
  unsigned char  ReadBuffer[100];
  unsigned long  ReadNum;  memset(ReadBuffer,0,sizeof(ReadBuffer));
  Result = ReadFile(hcom,ReadBuffer,sizeof(ReadBuffer),&ReadNum,NULL);
  Form1->RECommand->Lines->Add("Receive:\r"+ReadStr );
  if(Result)
    {
    for(int i=0;i<sizeof(ReadBuffer);i++)
      ReadStr = ReadStr + (char)ReadBuffer[i];
    if(sizeof(ReadStr) == 4)
        ReadStr = "0";
    }
RECommand->Lines->Add(ReadStr );
  return 1;
}
//在这里我发送的是字符串。
bool __fastcall TForm1::SendStrToPort(AnsiString ReadStr)
{
bool Result;
unsigned char B[100];
unsigned long  SendNum;
for(int i=1;i<=ReadStr.Length();i++)
  {
    B[i-1]= (int)ReadStr[i];
  }
  SendNum = ReadStr.Length();
  WriteFile(hcom,B,SendNum,&SendNum,NULL);
  if(!WriteFile(hcom,B,SendNum,&SendNum,NULL))
    {
    Result = false;
    if(Application->MessageBox("without write", NULL, MB_OKCANCEL) != IDOK)
      exit(1);
    }
return Result;
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Answer 2

太长了
其实就是：初始化
修改串口的一些参数，比如说波特率之类的然后用writefile，如果读取，请用readfile