Hi Monks, I am trying to use the Device::SerialPort() module from the CPAN perl library & I seem to be having some issue reading the values back for the command I send to serial port. I send some command to the Serial Port & when trying to read the value back, I see some garbage being readout. How can i really tell whether my command did go through OK. As a matter of fact, I know that the Serial Port is being opened by the perl scripts because at the same time when I tried opening up the same port using other application I cannot. Below is the piece of code that I have.

my $PortName = '/dev/ttyS16' ;
my $PortObj = new Device::SerialPort($PortName) || die "Can't open $Po
+rtName: $!\n";

$PortObj->databits(8);
$PortObj->baudrate(19200);
$PortObj->parity("none");
$PortObj->stopbits(1);
#$PortObj->flowcontrol("none");

$PortObj->write('asic_rst 0');
my ($r1, $saw1) = $PortObj->read(255) ;

$PortObj->write("asic_rst 1");
my ($r2, $saw2) = $PortObj->read(255) ;

$PortObj->close || die "failed to close";
undef $PortObj;
[download]

The values of the return variables is as follows.

r1 = 8
$saw1 = a®k}r.\x17‚

r2 = 8
$saw1 = a®k}r.\x17Š
[download]

How do i know what is being read in $saw1/$saw2 is correct ? I know my response to the serial port is not what I am seeing here.Also note that instead of read i tried input() & lookfor() commands as well. Any input is appreciated.

Ok, so now I based on the recommendations from lot of monks, I have switched from Device::SerialPort (cygwin) to Win32::SerialPort. Below is the code. And also the output response. Basically I am still seeing the same scribbled data when trying to read. I am at all lost here.

#!/usr/bin/perl -w
use strict;
use warnings ;
use Win32::SerialPort qw( :STAT ) ;  
# }

 my $PortName = 'COM17' ;
 my $serial_port = new Win32::SerialPort($PortName) || die "Can't open
+ $PortName: $!\n";
 $serial_port->databits( 8 );
 $serial_port->baudrate(19200);
 $serial_port->parity("none");
 $serial_port->stopbits( 1 );
 $serial_port->handshake("rts") ;
 my $response = undef ;
 my $complete = 0 ;

my $command = "12345" ;
$serial_port->write("$command\r") ;
sleep 1 ;
  
my ( $blocking_flags, $in_bytes, $out_bytes, $latch_error_flags ) = $s
+erial_port->status() ;
print("1: $blocking_flags\n") ;
print("2: $in_bytes\n") ;
print("3: $out_bytes\n") ;
print("4: $latch_error_flags\n") ;

$serial_port->lookclear; #clear the buffer 
sleep (2) ;
 
 
if( $in_bytes > 0 )
{
    for( my $i = 0 ; $i < $in_bytes ; $i++ )
    {
            # Get a byte at a time to process.
            $response .= $serial_port->read( 1 ) ;

            if( $response =~ /\r/ )
            {
               $complete = 1 ;
            }
         }
      }

print ("Response is: $response\n") ;
 
$serial_port->close || die "failed to close";
undef $serial_port;                               # frees memory back
[download]

 
1: 0
2: 5
3: 0
4: 0
Response is: 1ªó5├
[download]

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