unit1.~pas

RS232串口通讯随书源码

unit Unit1;

interface

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

type
  TForm1 = class(TForm)
    rdCOM: TRadioGroup;
    Label1: TLabel;
    mSend: TMemo;
    Label2: TLabel;
    mReceive: TMemo;
    btnOpenPort: TButton;
    btnSend: TButton;
    btnEnd: TButton;
    Timer1: TTimer;
    procedure btnSendClick(Sender: TObject);
    procedure btnOpenPortClick(Sender: TObject);
    procedure btnEndClick(Sender: TObject);
    procedure Timer1Timer(Sender: TObject);
    procedure mSendKeyPress(Sender: TObject; var Key: Char);
  private
    { Private declarations }
  public
    { Public declarations }
    procedure OpenComm;  //打开通信端口
  end;

var
  Form1: TForm1;
  hComm: THandle;


implementation

{$R *.DFM}

procedure TForm1.btnSendClick(Sender: TObject);
var
  Temp:string;
  lrc:LongWord;
begin
  if (hComm=0) then exit;
  Temp:=msend.Text ;
  WriteFile(hComm,Pointer(Temp)^,Length(Temp), lrc, nil); //送出数据
end;

procedure TForm1.btnOpenPortClick(Sender: TObject);

begin
  //若通信端口已打开，则不需要再打开
  if (hComm<>0) then begin
    ShowMessage('通信端口已打开!不需再开!');
    exit;
  end;
  OpenComm;
end;

//以下是打开通信端口的程序
procedure TForm1.OpenComm;
var
  cc:TCOMMCONFIG;
  Temp:string;
begin
  Temp:='COM'+inttostr(rdcom.ItemIndex+1);                          //选择所要打开的COM
  hComm:=CreateFile(PChar(Temp), GENERIC_READ or GENERIC_WRITE,
       0, nil, OPEN_EXISTING, 0, 0);                   //打开COM
  if (hComm = INVALID_HANDLE_VALUE) then begin         //如果COM 未打开
    MessageBox (0, '打开通信端口错误!!','',MB_OK);
    exit;
  end;

  GetCommState(hComm,cc.dcb);                         // 得知目前COM 的状态
  cc.dcb.BaudRate:=CBR_9600;                          // 设置波特率为9600
  cc.dcb.ByteSize:=8;                                 // 字节为 8 bit
  cc.dcb.Parity:=NOPARITY;                            // Parity 为 None
  cc.dcb.StopBits:=ONESTOPBIT;                        // 1 个Stop bit

  if not SetCommState(hComm, cc.dcb) then begin       // 设置COM 的状态
    MessageBox (0, '通信端口设置错误!!!','',MB_OK);
    CloseHandle(hComm);
    exit;
  end;
end;

procedure TForm1.btnEndClick(Sender: TObject);
begin
   CloseHandle(hComm);//关闭通信端口
   close;//结束程序
end;


//定时器事件
procedure TForm1.Timer1Timer(Sender: TObject);
  var
  Temp : string;
  inbuff: array[0..2047] of Char;
  nBytesRead, dwError:LongWORD ;
  cs:TCOMSTAT;
  begin
   ClearCommError(hComm,dwError,@CS);  //取得状态
   if cs.cbInQue =0 then exit;
   if cs.cbInQue > sizeof(inbuff) then begin
     PurgeComm(hComm, PURGE_RXCLEAR);  // 清除COM 数据