Delphi -7段显示

Question

我在试着解决一个问题。我想在7段显示器上显示多个I/O函数(write_byte())。我使用的是PCF8574 iic。我尝试将两个I/O函数添加到一起，但一次只有一个段变为红色。我如何才能让多个数据段同时变红并保持一段时间呢？

以下是我的代码

unit check;

interface

uses
  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
  Vcl.Controls, Vcl.Forms, Vcl.Dialogs, i2cUsb, Vcl.StdCtrls;

type
  TForm1 = class(TForm)
    Button1: TButton;
    Button2: TButton;
    Button3: TButton;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);

  private
    { private-declarationen }
  public
    { public-declarationen }
  end;

var
  Form1: TForm1;
  board, slave : Ti2cUsb;
  var1:integer;
  i: integer;

implementation
{$R *.dfm}

procedure TForm1.Button1Click(Sender: TObject);
begin

board := Ti2cUsb.Create;
slave := Ti2cUsb.Create;
//Comport Number COM4
var1 := board.Init(4);
Sleep(1000);
board.relais_on;
Sleep(1000);
board.relais_off;

end;

procedure TForm1.Button2Click(Sender: TObject);

begin

board.start_iic(False,64,'w');
{
// 7 Segment off:
board.wr_byte_iic($FF);
//all 7 Segments:
board.wr_byte_iic($7F);
board.wr_byte_iic($BF);
board.wr_byte_iic($DF);
board.wr_byte_iic($EF);
board.wr_byte_iic($F7);
board.wr_byte_iic($FB);
board.wr_byte_iic($FD);
board.wr_byte_iic($FE);
}

// Display off
        board.wr_byte_iic($FF);
        sleep(5000);


//number 0:
      board.wr_byte_iic($7F);
      board.wr_byte_iic($BF);
      board.wr_byte_iic($DF);
      board.wr_byte_iic($F7);
      board.wr_byte_iic($FB);
      board.wr_byte_iic($FD);
      sleep(5000);

//number 1:
      board.wr_byte_iic($DF);
      board.wr_byte_iic($F7);
      sleep(5000);


//number 2:
      board.wr_byte_iic($BF);
      board.wr_byte_iic($DF);
      board.wr_byte_iic($FE);
      board.wr_byte_iic($FD);
      board.wr_byte_iic($FB);
      sleep(5000);

//number 3:
      board.wr_byte_iic($BF);
      board.wr_byte_iic($DF);
      board.wr_byte_iic($FE);
      board.wr_byte_iic($F7);
      board.wr_byte_iic($FB);
      sleep(5000);

//number 4:
      board.wr_byte_iic($7F);
      board.wr_byte_iic($FE);
      board.wr_byte_iic($DF);
      board.wr_byte_iic($F7);
      board.wr_byte_iic($EF);
      sleep(5000);

//number 5:
      board.wr_byte_iic($BF);
      board.wr_byte_iic($7F);
      board.wr_byte_iic($FE);
      board.wr_byte_iic($F7);
      board.wr_byte_iic($FB);
      sleep(5000);

//number 6:
      board.wr_byte_iic($EF);
      board.wr_byte_iic($BF);
      board.wr_byte_iic($7F);
      board.wr_byte_iic($FD);
      board.wr_byte_iic($FB);
      board.wr_byte_iic($F7);
      board.wr_byte_iic($FE);
      sleep(5000);

//number 7:
      board.wr_byte_iic($BF);
      board.wr_byte_iic($DF);
      board.wr_byte_iic($F7);
      sleep(5000);

//number 8:
      board.wr_byte_iic($FF);
      board.wr_byte_iic($7F);
      board.wr_byte_iic($BF);
      board.wr_byte_iic($DF);
      board.wr_byte_iic($F7);
      board.wr_byte_iic($FB);
      board.wr_byte_iic($FD);
      board.wr_byte_iic($FE);
      sleep(5000);

//number 9:
      board.wr_byte_iic($EF);
      board.wr_byte_iic($FE);
      board.wr_byte_iic($7F);
      board.wr_byte_iic($BF);
      board.wr_byte_iic($DF);
      board.wr_byte_iic($F7);
      board.wr_byte_iic($FB);
      sleep(5000);

// Display off
      board.wr_byte_iic($FF);



end;

end.

提前感谢！

Answer 1

当您尝试写入多个段时，每次写入都会替换先前写入的内容。你需要计算出与你想要显示的段的组合相对应的数字，然后写一次组合的数字。

有许多方法可以做到这一点。我想我会这样做：

implementation
  const      ALL_OFF   = $ff;
  const      SEGMENT_1 = $20;      // ONE bit only set, the bit that needs to
  const      SEGMENT_2 = $08;      //     turned off for that segment

procedure SetNumberOne();
var
  ByteToWrite: Byte;
begin
  ByteToWrite := ALL_OFF Xor (SEGMENT_1 Or SEGMENT_2);
  board.wr_byte_iic(ByteToWrite);
end;

因此，您可以使用常量标记需要关闭的位，将这些常量Or在一起以获得正确的位组合，然后使用$FF关闭与您要显示的段相对应的位。