libmaple/libmaple/iwdg.c

/******************************************************************************
 * The MIT License
 *
 * Copyright (c) 2010 Michael Hope.
 *
 * Permission is hereby granted, free of charge, to any person
 * obtaining a copy of this software and associated documentation
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/**
 * @file libmaple/iwdg.c
 * @brief Independent watchdog (IWDG) support
 */

#include <libmaple/iwdg.h>

/**
 * @brief Initialise and start the watchdog
 *
 * The prescaler and reload set the timeout.  For example, a prescaler
 * of IWDG_PRE_32 divides the 40 kHz clock by 32 and gives roughly 1
 * ms per reload.
 *
 * @param prescaler Prescaler for the 40 kHz IWDG clock.
 * @param reload Independent watchdog counter reload value.
 */
void iwdg_init(iwdg_prescaler prescaler, uint16 reload) {
   IWDG_BASE->KR = IWDG_KR_UNLOCK;
   IWDG_BASE->PR = prescaler;
   IWDG_BASE->RLR = reload;

   /* Start things off */
   IWDG_BASE->KR = IWDG_KR_START;
   iwdg_feed();
}

/**
 * @brief Reset the IWDG counter.
 *
 * Calling this function will cause the IWDG counter to be reset to
 * its reload value.
 */
void iwdg_feed(void) {
    IWDG_BASE->KR = IWDG_KR_FEED;
}