:mod:`watchdog`
===============

.. py:module:: watchdog

.. autoapi-nested-parse::

   Watchdog Timer

   The `watchdog` module provides support for a Watchdog Timer. This timer will reset the device
   if it hasn't been fed after a specified amount of time. This is useful to ensure the board
   has not crashed or locked up. Note that on some platforms the watchdog timer cannot be disabled
   once it has been enabled.

   The `WatchDogTimer` is used to restart the system when the application crashes and ends
   up into a non recoverable state. Once started it cannot be stopped or
   reconfigured in any way. After enabling, the application must "feed" the
   watchdog periodically to prevent it from expiring and resetting the system.

   Example usage::

       from microcontroller import watchdog as w
       from watchdog import WatchDogMode
       w.timeout=2.5 # Set a timeout of 2.5 seconds
       w.mode = WatchDogMode.RAISE
       w.feed()



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.. py:class:: WatchDogMode

   run state of the watchdog timer

   Enum-like class to define the run mode of the watchdog timer.

   .. py:attribute:: RAISE
      :annotation: :WatchDogMode

      Raise an exception when the WatchDogTimer expires.

      :type WatchDogMode:


   .. py:attribute:: RESET
      :annotation: :WatchDogMode

      Reset the system if the WatchDogTimer expires.

      :type WatchDogMode:



.. py:class:: WatchDogTimer

   Timer that is used to detect code lock ups and automatically reset the microcontroller
   when one is detected.

   A lock up is detected when the watchdog hasn't been fed after a given duration. So, make
   sure to call `feed` within the timeout.

   Not currently dynamically supported. Access the sole instance through `microcontroller.watchdog`.

   .. py:attribute:: timeout
      :annotation: :float

      The maximum number of seconds that can elapse between calls
      to feed()


   .. py:attribute:: mode
      :annotation: :WatchDogMode

      The current operating mode of the WatchDogTimer `watchdog.WatchDogMode`.

      Setting a WatchDogMode activates the WatchDog::

        import microcontroller
        import watchdog

        w = microcontroller.watchdog
        w.timeout = 5
        w.mode = watchdog.WatchDogMode.RAISE


      Once set, the WatchDogTimer will perform the specified action if the timer expires.


   .. py:method:: feed() -> None

      Feed the watchdog timer. This must be called regularly, otherwise
      the timer will expire.


   .. py:method:: deinit() -> None

      Stop the watchdog timer. This may raise an error if the watchdog
      timer cannot be disabled on this platform.