.. _faq_watchdog:

Use of Watchdog in Applications
###############################

Zephyr provides watchdog support natively. There are two types of watchdog in a typical system:

i) System Level watchdog using hardware watchdog timer and
ii) Task Watchdog for various individual Application Threads.

System Level Watchdog using Hardware Watchdog Timer
***************************************************

This uses hardware watchdog to monitor kernel, drivers and other system software modules.
The watchdog driver source is in ``zephyr/drivers/watchdog/*cmsdk*`` files, and is included
by default for Atmosic platforms.

Individual Applications in its ``main()`` function is responsible for installing, configuring
and enabling this System watchdog. Look for ``wdt_install_timeout()``, ``wdt_setup()``,
``wdt_feed()`` usages in one of Atmosic Applications source in openair repository
(``openair/applications/ras_rrsp_reflector/src/main.c``, for example).

It is recommended that each application enables and uses System watchdog for healthy operation
of the system.

Task Watchdog for Various Application Threads
*********************************************

This typically uses Zephyr kernel provided software timers, ``task_wdt``. Use of this depends
upon individual applications requirements, depending upon how many application threads exist,
how complex they are and the need for health monitoring within application threads.

Additional Resources
********************

For additional details on Zephyr watchdog support refer to Zephyr documentation:

* `Watchdog Interface <https://docs.zephyrproject.org/4.3.0/doxygen/html/group__watchdog__interface.html>`_
* `Task Watchdog <https://docs.zephyrproject.org/4.3.0/services/task_wdt/index.html>`_