[Karsh]

Попробуйте так:

Код:

function ContinuousReadADCFrame(Chan: Byte; buf: Pointer; len: DWORD): BOOL; stdcall; external 'xxxx' index  6;

procedure TForm1.Button1Click(Sender: TObject);
var
   buf: array of char;
   Len: integer;
begin
   Len:= 512;
   SetLength(Buf, Len + 1);
   StartContinuousReadADC(0);
   ContinuousReadADCFrame(0, @Buf[0], Len);
   while not isADCXferComplete(0) do;
   StopContinuousReadADC(0);

   Finalize(Buf);
end;