نحوه برقراري ارتباط دلفي با پورتهاي com

ميتونيد اونا رو مثل يك فايل باز كنيد و توشون بنويسيد يا ازشون بخونيد
اين كد باز كردن پورت
کد:
procedure TMainForm.OpenPort(i:Integer);
{}
  Procedure InitSerial;
  Var
    DCB: TDCB;
    Config : String;
    CommTimeouts : TCommTimeouts;
  begin
    if not SetupComm(hCom, RxBufferSize, TxBufferSize) then
      showMessage('CanNot Setup Com Port');

    if not GetCommState(hCom, DCB) then
       showmessage('can not read com state')
    Else
    Begin
       Config :=Pchar('baud=19200 parity=n data=8 stop=1'+#0);

       if not BuildCommDCB(@Config[1], DCB) then
         ShowMessage('Can Not build com dcb')
       else
         if not SetCommState(hCom, DCB) then
           ShowMessage('Can Not set com state');
    End;

    with CommTimeouts do
    begin
      ReadIntervalTimeout := 0;
      ReadTotalTimeoutMultiplier := 0;
      ReadTotalTimeoutConstant := 1000;
      WriteTotalTimeoutMultiplier := 0;
      WriteTotalTimeoutConstant := 1000;
    end;

    if not SetCommTimeouts(hCom, CommTimeouts) then
          showMessage('Can not set com timeout');
  End;
begin
   CPN:=i;  //initialize serial Port to Boud=9600 Parity=none startbit=1
   hCom := CreateFile(PChar(ComPort),
                          Generic_Read,// Or GENERIC_WRITE,
                          0,
                          nil,
                          OPEN_EXISTING,
                          FILE_ATTRIBUTE_NORMAL,
                          0);
  if hCom = INVALID_HANDLE_VALUE then
    showMessage('Error Opening File')
  else
  Begin
    InitSerial;
  End;
end;
اينهم كد خواندن

کد:
function TMainForm.read1byteFromPort:byte;
Var
   d: array[1..1] of byte;
   s: String;
   BytesRead, i: cardinal;
Begin
    if not ReadFile (hCom, d, sizeof(d), BytesRead, Nil) then
       read1byteFromPort:=0
    Else
       read1byteFromPort:=d[1];
end;