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.. highlight:: c
.. _libmaple-iwdg:
``<libmaple/iwdg.h>``
=====================
Independent Watchdog (IWDG) support. The IWDG peripheral is common
across supported targets, so everything documented here is portable.
.. contents:: Contents
:local:
Usage Note
----------
To use the independent watchdog, first call :ref:`iwdg_init()
<libmaple-iwdg-iwdg_init>` with the appropriate prescaler and IWDG
counter reload values for your application. Afterwards, you must
periodically call :ref:`iwdg_feed() <libmaple-iwdg-iwdg_feed>` before
the IWDG counter reaches zero to reset the counter to its reload
value. If you do not, the chip will reset.
Once started, the independent watchdog cannot be turned off.
Devices
-------
None at this time.
Functions
---------
.. _libmaple-iwdg-iwdg_init:
.. doxygenfunction:: iwdg_init
.. _libmaple-iwdg-iwdg_feed:
.. doxygenfunction:: iwdg_feed
Types
-----
.. doxygenenum:: iwdg_prescaler
Register Maps
-------------
The register map is common on all supported targets. The base pointer
is ``IWDG_BASE``.
.. doxygendefine:: IWDG_BASE
.. doxygenstruct:: iwdg_reg_map
Register Bit Definitions
------------------------
Register bit definitions are common on all supported targets. They are
given as source code.
::
/* Key register */
#define IWDG_KR_UNLOCK 0x5555
#define IWDG_KR_FEED 0xAAAA
#define IWDG_KR_START 0xCCCC
/* Prescaler register */
#define IWDG_PR_DIV_4 0x0
#define IWDG_PR_DIV_8 0x1
#define IWDG_PR_DIV_16 0x2
#define IWDG_PR_DIV_32 0x3
#define IWDG_PR_DIV_64 0x4
#define IWDG_PR_DIV_128 0x5
#define IWDG_PR_DIV_256 0x6
/* Status register */
#define IWDG_SR_RVU_BIT 1
#define IWDG_SR_PVU_BIT 0
#define IWDG_SR_RVU (1U << IWDG_SR_RVU_BIT)
#define IWDG_SR_PVU (1U << IWDG_SR_PVU_BIT)
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