Windows CE Programming Serial Port - Getting Garbled Output
- by user576639
I am programming a Windows CE 6 device (Motorola MC3100 scanner Terminal). Using Lazarus FPC to compile it.
After 3 weeks work I reluctantly post here in the hope someone can suggest why I am getting garbled output from the serial port.
The code I am using is posted below. This is the standard code I have found from several places.
The OpenPort works OK.
When I send the string using SendString('ABCDEF') I get garbled input to the PC Serial port such as:
4[#131][#26][#0][#0][#0][#0] (the bracketed data indicates that it is a non-printable character ASCII Code)
Obviously it is connecting to the port OK AND it is sending the correct no of characters (7).
I have tried all combinations of Baud Rate, Data Bits, Parity and Stop Bits without any joy. Also tried changing cable, on a different PC etc.
Could it be I need to set something else in the DCB?
Any help or suggestions would be GREATLY appreciated.
unit Unit1;
{$mode objfpc}{$H+}
interface
uses
Classes, SysUtils, FileUtil, Forms, Controls, Graphics, Dialogs, StdCtrls, ExtCtrls,
Windows, LResources;
type
{ TForm1 }
TForm1 = class(TForm)
Button1: TButton;
Button2: TButton;
Label1: TLabel;
procedure Button1Click(Sender: TObject);
procedure Button2Click(Sender: TObject);
function OpenPort(ComPort:String;BaudRate,ByteSize,Parity,StopBits:integer):String;
procedure SendString(str:String);
private
{ private declarations }
public
{ public declarations }
end;
var
Form1: TForm1;
cc:TCOMMCONFIG;
Connected:Boolean;
implementation
{$R *.lfm}
var F: TextFile;
var hComm: THandle;
str: String;
lrc: LongWord;
{ TForm1 }
function
OpenPort(ComPort:String;BaudRate,ByteSize,Parity,StopBits:integer):String;
var
cc:TCOMMCONFIG;
SWide:WideString;
Port:LPCWSTR;
begin
SWide:=ComPort;
Port:=PWideChar(SWide);
result:='';
if (1=1) then begin
Connected:=False;
hComm:=CreateFile(Port, GENERIC_READ or GENERIC_WRITE,0, nil,OPEN_EXISTING,0,0);
if (hComm = INVALID_HANDLE_VALUE) then begin
ShowMessage('Fail to Open');
exit;
end;
GetCommState(hComm,cc.dcb);
cc.dcb.BaudRate:=BaudRate;
cc.dcb.ByteSize:=ByteSize;
cc.dcb.Parity:=Parity;
cc.dcb.StopBits:=StopBits;
if not SetCommState(hComm, cc.dcb) then begin
result:='SetCommState Error!';
CloseHandle(hComm);
exit;
end;
Connected:=True;
end;
end;
procedure TForm1.Button1Click(Sender: TObject);
begin
OpenPort('COM1:',9600,8,0,0);
end;
procedure TForm1.Button2Click(Sender: TObject);
begin
SendString('ABCDEFG');
end;
procedure TForm1.SendString(str:String);
var
lrc:LongWord;
begin
if (hComm=0) then exit;
try
if not PurgeComm(hComm, PURGE_TXABORT or PURGE_TXCLEAR) then
raise Exception.Create('Unable to purge com: ');
except
Exit;
end;
WriteFile(hComm,str,Length(str), lrc, nil);
end;
end.
