From: Anthony Walter (sysrpl@hotmail.com)
Subject: Re: Serial Port Baud Rate
Newsgroups: borland.public.delphi.winapi
Date: 1999/11/04


> I need to be able to set the baud rate of the serial port to a weird value
> (~7680 baud) to interface with a piece of 'intelligent' equipment.
>
> With all of the standard software, I appear to be limited to the usual
> values or get an error !!
>
> Any ideas . . . . .
>

It all depends on how you are accessing the COM port. If dealng with the API
and not a wrapper you can get a handle to a COM port like so:

  PortHandle := CreateFile('COM1', GENERIC_READ or GENERIC_WRITE, 0, nil,
   OPEN_EXISTING, 0, 0);

To fill out basic COM device infomation:

  GetCommProperties(PortHandle, ComProp);

To display a COM config dialog:

  CommConfigDialog('COM1', SomeForm.Handle, ComConfig);

In regards to you baud rate question, check out the VERY cool BuildCommDCB
function. It takes and init string such as 'baud=7680 parity=N data=8
stop=1' and converts it into a BCD. You can then bind that data to the COM
device using SetCommState(PortHandle, BCD). To re-initializes a
communications resource use the SetupComm function.

Of course all this stuff is SCREAMING for an object wrapper so I thought
this might help get you started with a class interface declaration ...

type
  TParity = (paEven, paMark, paNone, paOdd);

  TComPort = class
  private
    FDBC: TDBC;
    FHandle: THandle;
    FPort: Integer;
    function GetBaud: Integer;
    procedure SetBaud(const Value: Integer);
    procedure SetHandle(Value: THandle);
    function GetParity: TPariy;
    procedure SetParity(const Value: TPariy);
    procedure SetPort(Value: Integer);
  public
    constructor Create;
    destructor Destroy; override;
    procedure Open;
    procedure Close;
    function Init(const InitStr: string): Boolean;
    property Baud: Integer read GetBaud write SetBaud;
    property Handle: THandle read FHandle write SetHandle;
    property Parity: TPariy read GetParity write SetParity;
    property Port: Integer read FPort write SetPort;
    function Read(var Buffer; Count: Cardinal): Integer;
    function Write(var Buffer; Count: Cardinal): Integer;
  end;

Anthony Walter
sysrpl@hotmail.com