unit1.pas

来自「在delphi中实现windows核心编程.原书光盘代码核心编程.原书光盘代码」· PAS 代码 · 共 57 行

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  StdCtrls;

type
  TForm1 = class(TForm)
    Button1: TButton;
    Button2: TButton;
    Button3: TButton;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
    procedure Button3Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

uses UnitPortTalk;

{$R *.DFM}

procedure Speed(count:word);
begin
  if not OpenPortTalk then exit;
  outportb($43,$34); {写入8253控制寄存器，设置写0号定时器}
  outportb($40,lo(count));  {写定时值低位}
  outportb($40,hi(count));  {写定时值高位}
  ClosePortTalk;
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
   Speed($6000); //慢
end;

procedure TForm1.Button2Click(Sender: TObject);
begin
   Speed($2ea5);   
end;

procedure TForm1.Button3Click(Sender: TObject);
begin
   Speed($500); //快
end;

end.