I am not able to read from my serial device. I can successfully write to it and this is verified by watching the status LED on the device. We have a few Ruby programmers in house and, just to verify that the device is definitely working, I had one of them try to do the same in ruby (send "254", "27", print getc), and it works fine. I like perl, so here I am.

The way that this device (an ADSSR4xPROXR, btw) works is, you send a series of commands to it, and it will then send back "85" which acknowledges that it received your commands. For example, sending "254" then "27" will enable reporting mode, to which the device will send back "85".

I have tried all of the following code, and while all of them successfully get my commands to the device, none of them will print the response from the device:

First

#!/usr/bin/perl

use strict;
use warnings;

my $port = "/dev/ttyUSB0";

open (SERIALPORT, "+<", "$port") or die "can't open $port. ";
print SERIALPORT chr(254);
print SERIALPORT chr(27);
my $result = getc(SERIALPORT);
print ord($result) . "\n";

close (SERIALPORT);
[download]

Second

#!/usr/bin/perl

use strict;
use warnings;

my $port = "/dev/ttyUSB0";

open (SERIALPORT, "+<", "$port") or die "can't open $port. ";
select(SERIALPORT), $| = 1;
print SERIALPORT chr(254);
print SERIALPORT chr(27);
my $result = getc(SERIALPORT);
print ord($result) . "\n";

close (SERIALPORT);
[download]

Third

#!/usr/bin/perl

use strict;
use warnings;
use Device::SerialPort;

my $ob = Device::SerialPort->new("/dev/ttyUSB0") || die "Can't open po
+rt: $!";
$ob->baudrate(115200) || die "failed setting baudrate";
$ob->parity("none") || die "failed setting parity";
$ob->databits(8) || die "failed setting databits";
$ob->handshake("none") || die "failed setting handshake";
$ob->stopbits(1) || die "failed setting stopbits";
$ob->write_settings || die "failed writing settings";

my $cmd1 = chr(254);
my $cmd2 = chr(27);
$ob->write($cmd1);
$ob->write($cmd2);

open(LOG, ">>", "test2.txt") || die "can't open log file: $!";

open(DEV, "<", "/dev/ttyUSB0") || die "can't open prt: $_";

select(LOG), $| = 1;

while($_ = <DEV>) {
 print LOG $_;
}

undef $ob;
[download]

Fourth

#!/usr/bin/perl -w

use strict;
use warnings;
use Device::SerialPort;

my $port = Device::SerialPort->new("/dev/ttyUSB0");
$port->databits(8);
$port->baudrate(115200);
$port->parity("none");
$port->stopbits(1);
$port->handshake("on");
$port->write_settings;

$port->write(chr(254));
$port->write(chr(27));

my $char = $port->lookfor();
if ($char) {
 print "$char";
}
[download]

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