/**
   * @defgroup sys_can CAN (Controller Area Network)
   * @ingroup net
   * @brief RIOT CAN stack
   *
   * This module is a full CAN stack integrated to RIOT.
   * It includes a low-level interface, a data link layer, an ISO-TP layer and
   * a user interface.
   *
   * The low-level interface, candev, must be implemented by controler drivers.
   * The optional transceiver support can also be activated. Transceiver drivers must
   * then implement the trx_can interface.
   *
   * The data link layer is built around a device thread (one thread per CAN device),
   * and a common part. The common part is composed of the dll interface, for low-level
   * calls (from the device) and the raw interface for upper-level calls.
   * Internally it also uses the pkt module to allocate frames and the router module
   * to manage CAN filters.
   *
   * The ISO-TP layer uses the data link layer to send and receive CAN frames.
   *
   * Finally, the connection layer is the user interface to send and receive raw
   * CAN frames or ISO-TP datagrams.
   *
   * @see drivers_can
   */