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Device::SerialPort on debian Buster

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Martin McCormick
July 10, 2019 13:53
Device::SerialPort on debian Buster
Message ID:
	Before I take this too far, I want to make sure I am not
doing something wrong with use of the Device::SerialPort module
in perl.

	The code below talks to what it thinks is a RS-232 serial
port and controlls a radio scanner so that one can program the
scanner's settings and enter frequency and operational data.
Don't worry about all that.  It used to work on debian stretch
which is last year's version of debian.  After an upgrade to
buster which is this year's version, also known as debian 10, all
RS-232 ports appear to be dead.  Interestingly enough, a debian
system running stretch, containing perl was upgraded to buster
and serial communications between that system and a native serial
port on it's mother board are fine.  The very same code ported to
the buster system also fails with
Can't call method "baudrate" on an undefined value at /home/martin/etc/mm line 121.

	It doesn't matter what serial port or whether it is
native mother board hardware or what.  Serial ports are all
broken right now.

	Here is the scanner control code.  I am sending it to see
if I am using some deprecated method that is wrong to set the
serial port or we really do have big trouble.

	Thanks for any and all constructive ideas.  Code follows:

#!/usr/bin/perl -w
use strict;
use warnings::unused;
use File::Basename;
use File::Copy;
use File::Spec;
use Time::Local;
use Device::SerialPort;

sub waitfor {    #Receive from serial port.

    my $received = "";
    our $port;

    until ( "" ne $received ) {
        $received = $port->lookfor;
    return ($received);
}    #Receive from serial port.

#no more sub routine code past this point

#main global variables
our @dbstrings;

#main local variables
my $response;
my $cmd    = "";
my $ONEARG = "";

#my $counter = 1;

#Setup the comm port.
my $dev = "/dev/ttyACM0";
our $instring = "";
our $port     = Device::SerialPort->new("$dev");
$port->read_const_time(500);    # 500 milliseconds = 0.5 seconds
$port->are_match( "\r", "\n", );    # possible end strings

foreach $ONEARG (@ARGV) {           #each argument
    $ONEARG =~ s/^\s+//;
    $ONEARG =~ s/\s+$//;
    $cmd = $cmd . " " . $ONEARG;
    $cmd =~ s/^\s+//;
    $cmd =~ s/\s+$//;
}    #each argument

$cmd = uc $cmd;
$instring = waitfor;
my @chars = split( "", $instring );
foreach my $char (@chars) {    #

    #print ord($char);
    if ( $char =~ /[\,\s\.\-\+\_0-9A-Za-z]/ ) {    #printable
        $response = $response . $char;
    }    #printable
}    #
print "$response\n";
$instring = "";

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