tcomm1.pas

串口数据传输,用Tcomm或MSComm控件

     dcb.Flags := 1; //必须指定为1
     dcb.Parity := Ord( FParity );//Parity的指定
     FParityCheck:=False;
     if Ord(FParity)<>0 then FParityCheck:=True;
     if FParityCheck then
        dcb.Flags := dcb.Flags or dcb_ParityCheck;          // Enable parity check
     // 设置硬件流量控制
     Case FHwHandShaking of
      hhNone:;
      hhNoneRTSON:
          dcb.Flags := dcb.Flags or dcb_RTSControlEnable;
      hhRTSCTS:
          dcb.Flags := dcb.Flags or dcb_RTSControlHandShake or dcb_OutxCtsFlow;
     end;
     //设置软件流量控制
     Case FSwHandShaking of
      shNone:;
      shXonXoff:
          dcb.Flags := dcb.Flags or dcb_OutX or dcb_InX;
     end;
     //设置数据位数
     dcb.ByteSize := Ord( FDataBits ) + 5;
     //设置停止位数
     dcb.StopBits := Ord( FStopBits );
     //将设置写入
     SetCommState( hComm, dcb )
end;

procedure TComm.SetPortOpen(b:Boolean);
begin
  if b then //若指定打开通信端口，则…
  begin
   if FPortOpen then
   begin
     MessageDlg('COM Port has been opened!', mtError, [mbOK], 0);
     exit;
   end; //FportOpen loop
   OpenComm; //打开通信端口
   exit;
  end; //b loop
  CloseComm;
end;

//指定传输速度
procedure TComm.SetBaudRate( Rate : TBaudRate );
begin
     if Rate = FBaudRate then
        Exit;
     FBaudRate := Rate;
     if hComm <> 0 then
        _SetCommState
end;

//硬件流量控制
procedure TComm.SetHwHandShaking( c: THwHandShaking);
begin
     if c = FHwHandShaking then
        Exit;
     FHwHandShaking := c;
     if hComm <> 0 then
        _SetCommState
end;

//软件交握指定
procedure TComm.SetSwHandShaking( c : TSwHandShaking );
begin
     if c = FSwHandShaking then
        Exit;
     FSwHandShaking := c;
     if hComm <> 0 then
        _SetCommState
end;

//设置数据位数
procedure TComm.SetDataBits( Size : TDataBits );
begin
     if Size = FDataBits then
        Exit;
     FDataBits := Size;
     if hComm <> 0 then
        _SetCommState
end;

//设置极性检查方式
procedure TComm.SetParity( p : TParity );
begin
     if p = FParity then
        Exit;
     FParity := p;
     if hComm <> 0 then
        _SetCommState
end;

//设置停止位
procedure TComm.SetStopBits( Bits : TStopBits );
begin
     if Bits = FStopBits then
        Exit;
     FStopBits := Bits;
     if hComm <> 0 then
        _SetCommState
end;

//读取CD状态
function TComm.ReadCDHolding():Boolean;
begin
   Result:=FCDHolding;
end;

//读取DSR状态
function TComm.ReadDSRHolding():Boolean;
begin
   Result:=FDSRHolding;
end;

//读取RI状态
function TComm.ReadRIHolding():Boolean;
begin
   Result:=FRIHolding;
end;

//读取CTS状态
function TComm.ReadCTSHolding():Boolean;
begin
   Result:=FCTSHolding;
end;

//设置DTR状态
procedure TComm.SetDTRStatus(b:Boolean);
begin
  if hComm=0 then exit ;
  FDTR:=b;
  if b then
   EscapeCommFunction(hComm,SETDTR) //将DTR升至高电压
  else
   EscapeCommFunction(hComm,CLRDTR);//将DTR降至低电压
end;

//设置RTS状态
procedure TComm.SetRTSStatus(b:Boolean);
begin
  if hComm=0 then
   begin
    ECommError.Create('COM Port is not opened yet!');
    exit ;
   end;
  FRTS:=b;
  if b then
   EscapeCommFunction(hComm,SETRTS) //将RTS升至高电压
  else
   EscapeCommFunction(hComm,CLRRTS); //将RTS降至低电压
end;

//返回数据
function TComm.ReadInputData():String;
begin
  if hComm=0 then
   begin
    ECommError.Create('COM Port is not opened yet!');
   end;
  //决定每一次的指令要返回多少的字符(以Byte为单位)
  ReadProcess;
  Result:=FInputData;
end;

//返回数据
function TComm.ReadInputByte(var AP:PByte):DWORD;
begin
  if hComm=0 then
  begin
    ECommError.Create('COM Port is not opened yet!');
  end;
  ReadProcess;//执行读取函数
  AP:= @FInputByteData[0];//取得数据地址
  Result:=High(FInputByteData);//取得数据数组的最高索引值
end;


//读取数据的字节数
function TComm.ReadInDataCount():DWORD;
var
    CS:         TCOMSTAT;
    dwCommError:DWORD;
begin
  ClearCommError(hComm,dwCommError,@CS);  //取得状态
  Result:=CS.cbInQue;
end;

//清空数据缓冲区
procedure TComm.SetInDataCount(StrNO:DWORD);
begin
 if StrNo<>0 then exit ;
 PurgeComm(hComm, PURGE_RXCLEAR)  // 清除COM 数据
end;

//线路状态的数值
function TComm.ReadCommEvent():DWORD;
begin
  Result:=FCommEvent;
end;

//错误状态值的读取
function TComm.ReadCommError():DWORD;
begin
  Result:=FCommError;
end;


//设置引发接收事件的阀值
procedure TComm.SetRThreshold(RTNo:DWORD);
begin
  FRThreshold:=RTNo;
end;

//以下是实际的读取动作
Procedure TComm.ReadProcess;
var
   nBytesRead:            DWORD;
   dwCommError:           DWORD;
   CS:                    TCOMSTAT;
   i,ReadLen:             DWORD;
begin
     //使用ClearCommError得知有多少的数据在缓冲区中
     //并得知错误种类
     ClearCommError(hComm,dwCommError,@CS);  //取得状态
     FCommError:=dwCommError; //错误数值
     if cs.cbInQue <>0 then //若缓冲区有数据，则读取
     begin
       if InputLen=0 then //指定读取的数据数
         ReadLen:=cs.cbInQue
       else
         ReadLen:=InputLen;
       if cs.cbInQue > sizeof(szInputBuffer) then
         PurgeComm(hComm, PURGE_RXCLEAR)  // 清除COM 数据
       else
         begin
           //读取数据
           if ReadFile(hComm, szInputBuffer,ReadLen,nBytesRead,nil) then // 接收COM 的数据
           begin
             //取出数据
             FInputData:=Copy(szInputBuffer,1,ReadLen);

          // FInputData:=szInputBuffer; //add by hs

             //设置字节数组长度
             SetLength(FInputByteData,ReadLen);
             //将数据搬到数组中
               for i:=0 to ReadLen-1 do
                FInputByteData[i]:=ord(szInputBuffer[i]);
           end;  //ReadFile Loop
         end;//else Loop
     end; //cs.binQue Loop
     
   //  datacount:=0;  //add by hs
end;

//取得线路的状态
procedure TComm.GetModemState;
var
   dwModemState : DWORD;
begin
     if hComm=0 then
     begin
      raise ECommError.Create('COM Port is not opened yet!');
     end;
     //取得线路状态
     FCommEvent:=0;
     if GetCommModemStatus( hComm, dwModemState ) then
      begin
       //判断CD状态
       if (dwModemState and  MS_RLSD_ON)=MS_RLSD_ON then
        begin
          if not FCDHolding then FCommEvent:= EV_RLSD;
          FCDHolding:=True;
        end
       else
        begin
          if FCDHolding then FCommEvent:= EV_RLSD;
          FCDHolding:=False;
        end;
       //判断DSR状态
       if (dwModemState and  MS_DSR_ON)=MS_DSR_ON then
        begin
          if not FDSRHolding then FCommEvent:=FCommEvent + EV_DSR;
          FDSRHolding:=True;
        end
       else
        begin
          if FDSRHolding then FCommEvent:=FCommEvent + EV_DSR;
          FDSRHolding:=False;
        end;
       //判断RI状态
      if (dwModemState and  MS_RING_ON)=MS_RING_ON then
        begin
          if not FRIHolding then FCommEvent:=FCommEvent + EV_RING;
          FRIHolding:=True;
        end
       else
        begin
          if FRIHolding then FCommEvent:=FCommEvent + EV_RING;
          FRIHolding:=False;
        end;
      //判断CTS状态
      if (dwModemState and  MS_CTS_ON)=MS_CTS_ON then
        begin
          if not FCTSHolding then FCommEvent:=FCommEvent + EV_CTS;
          FCTSHolding:=True;
        end
       else
        begin
          if FCTSHolding then FCommEvent:=FCommEvent + EV_CTS;
          FCTSHolding:=False;
        end;
      end;
end;


procedure Register;
begin
     RegisterComponents('System', [TComm])
end;
//组件的定时器程序，在此会决定事件是否被触发
procedure TComm.ProcTimer(Sender: TObject);
var
 tmpValue:   DWORD;
 dwCommError:DWORD;
 CS:         TCOMSTAT;
begin
    if hComm=0 then exit;
    //若设置读取的字符数，检查并触发事件
     ClearCommError(hComm,dwCommError,@CS);  //取得状态
     FCommError:=dwCommError; //错误数值
    if FRThreshold>0 then
    begin
     if cs.cbInQue >=FRthreshold then
       ReceiveData();
    end;
    GetModemState;
    Application.ProcessMessages; //看有无其它的指令需执行，以免锁住
    //检查线路状态是否发生改变，若改变则触发事件
    tmpValue:=ReadCommEvent;
    if tmpValue<>0 then  ModemStateChange(tmpValue);
     Application.ProcessMessages; //看有无其它的指令需执行，以免锁住
    //若发生错误，则引发错误
    tmpValue:=ReadCommError;
    if tmpValue<>0 then ReceiveError(tmpValue);
     Application.ProcessMessages; //看有无其它的指令需执行，以免锁住
end;

end.