高分请教：串口不能发送数据！

Question

串口参数有没有问题？
还有你的硬件是否OK？

Answer 1

没看到有串口初始化的代码
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Answer 2

没看到有串口初始化的代码
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Answer 3

我有一个串口测试小程序，你可以检查一下硬件故障

Answer 4

初始化应该没错，因为读线程是正确的
程序如下：
function TMainFrm.OpenCommPort(Port: string): integer;
begin
        //open comm port;
        try
            hCom := CreateFile(Pchar(Port),
                               GENERIC_READ or GENERIC_WRITE,
                               0,//独占式访问
                               nil,
                               OPEN_EXISTING,
                               FILE_FLAG_OVERLAPPED,
                               0);
            if hCom=INVALID_HANDLE_VALUE then begin
                showmessage('打开串口' + Port + '错误！');
                abort;
            end;
        except
            Showmessage('打开串口失败！');
            abort;
        end;
        //Result := True;        if not SetupParameter() then begin
            CloseHandle(hCom);
            abort;
        end;
        MainFrm.statusBar1.Panels[0].Text := '端口：' + SetupFrm.PortLst.Text;
        EscapeCommFunction(hCom, SETDTR);
        EscapeCommFunction(hCom, SETRTS);        Rt := TReadThread.Create(false);
        Rt.hCom := hCom;        Result := hCom;
end;设置：
function TMainFrm.SetupParameter(): boolean;
var
    cto : TCommTimeOuts;
    dcb : TDCB;
    dcbFlag : integer;
    tmpStr : string;
begin
        //Setup Comm Configration
        try
            SetCommMask(hCom, EV_RXCHAR);
            SetupComm(hCom, 4096, 4096);
            PurgeComm(hCom, PURGE_RXABORT or PURGE_RXCLEAR or PURGE_TXABORT or PURGE_TXCLEAR);
            cto.ReadIntervalTimeout := $ffffffff;
            cto.ReadTotalTimeoutConstant := StrToInt(SetupFrm.TimeOutEdt.Text);
            StatusBar1.Panels[5].text := '超时：' + SetupFrm.TimeOutEdt.Text + '毫秒';
            cto.ReadTotalTimeoutMultiplier := 0;
            cto.WriteTotalTimeoutConstant := 0;
            cto.WriteTotalTimeoutMultiplier := 2*CBR_9600 div CBR_19200;
            SetCommTimeOuts(hCom, cto);
        except
            Beep;
            Showmessage('串口超时设置失败！');
            abort;
        end;
        try
            dcb.DCBlength := sizeof(TDCB);
            GetCommState(hCom,dcb);
            dcb.BaudRate := strToInt(SetupFrm.CBRLst.Text);
            StatusBar1.Panels[1].Text := '波特率：' + SetupFrm.CBRLst.Text;
            dcb.ByteSize := strToInt(SetupFrm.ByteSizeLst.Text);
            StatusBar1.Panels[2].Text := '比特长：' + SetupFrm.ByteSizeLst.Text + '位';
            case SetupFrm.StopBitsLst.ItemIndex of
                0 : dcb.StopBits := ONESTOPBIT;
                1 : dcb.StopBits := ONE5STOPBITS;
                2 : dcb.StopBits := TWOSTOPBITS;
            end;
            //dcb.StopBits := strToInt(SetupFrm.StopBitsLst.Text);
            StatusBar1.Panels[3].Text := '停止位：' + SetupFrm.StopBitsLst.Text + '位';
            case SetupFrm.CheckLst.ItemIndex of
                0:  begin
                    dcb.Parity := NOPARITY;
                    tmpStr := '无校验';
                    end;
                1:  begin
                    dcb.Parity := ODDPARITY;
                    tmpStr := '奇校验';
                    end;
                2:  begin
                    dcb.Parity := EVENPARITY;
                    tmpStr := '偶校验';
                    end;
                3:  begin
                    dcb.Parity := MARKPARITY;
                    tmpStr := '标记校验';
                    end;
            end;
            StatusBar1.Panels[4].Text := '校验：' + tmpStr;
            dcb.XonChar := Chr($11);  //Ctrl_Q
            dcb.XoffChar := Chr($13); //Ctrl_S
            dcb.ErrorChar := Chr(0);
            dcb.XonLim := 100;
            dcb.XoffLim := 100;
            dcbFlag := 1;            //Binary must be True
            dcbFlag := dcbFlag or 2; //Parity Check True
            dcbFlag := dcbFlag or 4; //FOutxCtsFlowCtrl
            dcbFlag := dcbFlag or 8; //FOutxDsrFlowCtrl
            dcbFlag := dcbFlag or $20;   //DtrHandShake
            dcbFlag := dcbFlag or $1000; //RtsEnable
                //     dcbFlag := dcbFlag or $800;  //Ignore NULL Char
            dcb.Flags := dcbFlag;
            SetCommState(hCom, dcb);
            Connected := True;
        except
            Beep;
            Showmessage('串口参数设置失败！');
            abort;
        end;
        Result := True;
end;