Задержка в микроседундах

unit TimeDelayManager; 
 
interface 
 
uses Windows, Forms, Classes; 
 
type 
  TTimeDelayManager = class; 
 
  TTimerThread = class(TThread) 
  private 
    FOwner: TTimeDelayManager; 
  protected 
    procedure DoUserEvent; 
  public 
    constructor Create(CreateSuspended: Boolean; AOwner: TTimeDelayManager); 
  protected 
    procedure Execute; override; 
  end; 
 
  TTimeDelayManager = class(TComponent) 
  private 
    FHardTime: Boolean; 
    FDelay: LongWord; 
    FTimerThread: TTimerThread; 
    FOnTimer: TNotifyEvent; 
    procedure WaitPlease; 
  public 
    constructor Create(AOwner: TComponent); override; 
    procedure Start; 
    procedure StartAsThread; 
  published 
    property Delay: LongWord read FDelay write FDelay; 
    property HardTime: Boolean read FHardTime write FHardTime; 
    property OnTimer: TNotifyEvent read FOnTimer write FOnTimer; 
  end; 
 
procedure Register; 
 
implementation 
 
procedure Register; 
begin 
  RegisterComponents('Samples', [TTimeDelayManager]); 
end; 
 
{ TTimeDelayManager } 
 
constructor TTimeDelayManager.Create(AOwner: TComponent); 
begin 
  inherited Create(AOwner); 
  FDelay := 1000; 
  FHardTime := False; 
end; 
 
procedure TTimeDelayManager.WaitPlease; 
var 
  Frequency, EndTime, CurrentTime, WaitTime: Int64; 
begin 
  QueryPerformanceFrequency(Frequency); 
  WaitTime := Trunc((Frequency / 1000) * FDelay); 
  QueryPerformanceCounter(EndTime); 
  EndTime := EndTime + WaitTime; 
  repeat 
    if not FHardTime then 
      Application.ProcessMessages; 
    QueryPerformanceCounter(CurrentTime) 
  until (CurrentTime >= EndTime); 
end; 
 
procedure TTimeDelayManager.Start; 
begin 
  WaitPlease; 
  if Assigned(FOnTimer) then 
    FOnTimer(Self); 
end; 
 
procedure TTimeDelayManager.StartAsThread; 
begin 
  TTimerThread.Create(False, Self); 
end; 
 
{ TTimerThread } 
 
constructor TTimerThread.Create(CreateSuspended: Boolean; AOwner: TTimeDelayManager); 
begin 
  inherited Create(CreateSuspended); 
  FOwner := AOwner; 
end; 
 
procedure TTimerThread.Execute; 
begin 
  FOwner.WaitPlease; 
  Synchronize(DoUserEvent); 
end; 
 
procedure TTimerThread.DoUserEvent; 
begin 
  if Assigned(FOwner.FOnTimer) then 
    FOwner.FOnTimer(FOwner); 
end; 
 
end.