PHP-serial.class.php AIUTO!!!!

[Z171]

metti var_dump( $serial ); dopo l'if e vediamo cosa dice la classe su linux

ho inserito il codice così, non sapevo in quale if

<?php 
error_reporting(E_ALL); 
ini_set("display_errors", 1); 
define("PORT","dev/ttyACM0"); 
  
if (isset($_GET['action'])) { 
    var_dump( $serial ); 
        include "php_serial.class.php"; 
    $serial = new phpSerial(); 
    $serial->deviceSet(PORT); 
        $serial->confBaudRate(9600); 
        $serial->confParity("none"); 
        $serial->confCharacterLength(8); 
        $serial->confStopBits(1); 
        $serial->confFlowControl("none"); 
        $serial->deviceOpen(); 
        if ($_GET['action'] == "on") { 
            $serial->sendMessage("a"); 
    } else if ($_GET['action'] == "off") { 
            $serial->sendMessage("s"); 
        } 
    $read = $serial->readPort(); 
    print $read; 
        $serial->deviceClose(); 
} 
  
?>

ho anche reinstallato linux e apache, ora visualizzo tutto, ma il risultato è questo

Notice: Undefined variable: serial in /var/www/index.php on line 7
NULL
Warning: Specified serial port is not valid in /var/www/php_serial.class.php on line 111

Warning: Unable to set the baud rate : the device is either not set or opened in /var/www/php_serial.class.php on line 204

Warning: Unable to set parity : the device is either not set or opened in /var/www/php_serial.class.php on line 254

Warning: Unable to set length of a character : the device is either not set or opened in /var/www/php_serial.class.php on line 298

Warning: Unable to set the length of a stop bit : the device is either not set or opened in /var/www/php_serial.class.php on line 335

Warning: Unable to set flow control mode : the device is either not set or opened in /var/www/php_serial.class.php on line 376

Warning: The device must be set before to be open in /var/www/php_serial.class.php on line 137

Warning: Device must be opened in /var/www/php_serial.class.php on line 541

Warning: Device must be opened to read it in /var/www/php_serial.class.php on line 474