php-linux-gpio/examples/basic.php

<?php

require_once __DIR__."/../vendor/autoload.php";

use NoccyLabs\Gpio\Gpio;
use NoccyLabs\Gpio\GpioMapper\WiringPiMapper;

try {
    $gpio = new Gpio();
} catch (Gpio\Exception $e) {
    error_log("Error: {$e}");
}

// The mapper translates GPIO to logical pins and vice versa
$gpio->setMapper( new WiringPiMapper(2) );

// Access logical pin 0, since we got a mapper assigned. Otherwise this would
// be the actual GPIO0 pin. 
$led = $gpio[0]
    ->export()
    ->setDirection("output")
    ->setValue(0)
    ->dumpStatus(true);

$x = 0;
while(true) {
    $x = (int)(!$x);
    $led->setValue($x);
    usleep(500000);
}