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Posted by jis on September 9, 2007, 3:17 pm
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> jis wrote:
> >> jis wrote:
>
> >>>>> I am using Win32::serialport for reading a data through a scanner
> >>>>> which is connected to the serial port.
> >>>>> I use polling as below.But this consumes 99% of my CPU time. and
> >>>>> slows down the system.
> >>>>> while(!($data=~/\r/))
> >>>>> {
> >>>>> $data=$Scanner->input(); #read the scanner port
> >>>>> $labeldata=$labeldata.$data; #append
> >>>>> }
>
> >>>>> Is there any way I implement interrupts or events using perl. Or
> >>>>> is there any other method to solve this issue.
>
> >>>> Is there any particular reason you couldn't simply use a blocking
> >>>> read rather than a non-blocking one?
>
> >>> I am now trying to use $Scanner->lookfor which is a blocking read i
> >>> believe. But main issue now is I am using a perl tk window in the
> >>> program. The tk window needs continuous update.The call lookfor
> >>> takes me to unknownloop and prevents me from servicing tk window.
>
> >>> Appreciate your help.
>
> >> Do not use $Scanner->lookfor but create "timer" and test
> >> $Scanner->status value. Take a look to Tk::After and repeat()
> >> function. All PCs have 8-16 bytes buffer for COM ports and you can
> >> test $Scanner->status value say every 50 miliseconds and if status
> >> will indicate some bytes in input buffer then you will read this, in
> >> other case you will can to update some Tk widget. --
>
> >> Petr Vileta, Czech republic
> >> (My server rejects all messages from Yahoo and Hotmail. Send me your
> >> mail from another non-spammer site please.)- Hide quoted text -
>
> >> - Show quoted text -
>
> > thanks for tthe info.it was helpful. But is there any problem using
> > $scanner->lookfor?
> > It luks to me even lookfor polls the com port effectively .
>
> I never used lookfor() because I like to have all under my own control ;-)
>
> use Tk;
> use Tk::after
> use Win32::SerialPort;
>
> my $mw = MainWindow->new();
> # create some widgets here
> our $buffer = '';
> our $PortObj = Win32::SerialPort->new ('COM1', 1) or die "Can't open serial
> port COM1: $^E\n";
> $PortObj->baudrate(57600) or die "fail setting baud rate";
> $PortObj->parity("none") or die "fail setting parity";
> $PortObj->databits(8) or die "fail setting databits";
> $PortObj->stopbits(1) or die "fail setting stopbits";
> $PortObj->handshake('none') or die "fail setting handshake";
> $PortObj->write_settings or die "fail write settings";
> my $rpt = $mw->repeat(50, \&checkbuffer);
> # is you want to stop repeater then do $rpt->cancel
> MainLoop;
>
> sub checkbuffer
> {
> ($BlockingFlags, $InBytes, $OutBytes, $LatchErrorFlags) = $PortObj->status;
> return unless(InBytes);
> my ($count, $input) = $PortObj->read($InBytes);
> $buffer .= $input;
>
> }
>
> --
>
> Petr Vileta, Czech republic
> (My server rejects all messages from Yahoo and Hotmail. Send me your mail
> from another non-spammer site please.)- Hide quoted text -
>
> - Show quoted text -
That was cool.
But it wrote in slightly different way.
use Tk;
use Tk::after
use Win32::SerialPort;
my $mw = MainWindow->new();
# create some widgets here
our $buffer = '';
our $PortObj = Win32::SerialPort->new ('COM1', 1) or die "Can't open
serial
port COM1: $^E\n";
$PortObj->baudrate(57600) or die "fail setting baud rate";
$PortObj->parity("none") or die "fail setting parity";
$PortObj->databits(8) or die "fail setting databits";
$PortObj->stopbits(1) or die "fail setting stopbits";
$PortObj->handshake('none') or die "fail setting handshake";
$PortObj->write_settings or die "fail write settings";
my $rpt = $mw->repeat(50, \&checkbuffer);
# is you want to stop repeater then do $rpt->cancel
MainLoop;
sub checkbuffer
{
my($BlockingFlags, $InBytes, $OutBytes, $LatchErrorFlags) =
$Scanner->status;
if($InBytes)
{
my $data= 0;
my $labeldata= undef;
while(!($data=~/\r/))
{
$data=$Scanner->input(); #read the scanner port
$labeldata.= $data; #append
}
}
}
this works for me. any errors in this one?
cheers,
jis
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