Define the configuration:
<?php $config = [ // ... 'pdo.options' => [ 'dsn' => 'mysql:host=localhost;dbname=sample;charset=UTF8', 'username' => 'user', 'password' => 'pass', 'options' => [], 'attributes' => [], ], // ...
and register the service:
<?php $app->register(new IPC\Silex\Provider\PDOServiceProvider(), ['pdo.options' => $config['pdo.options']]);