stm32f4xx_hal_iwdg.c

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/* Includes ------------------------------------------------------------------*/
#include "stm32f4xx_hal.h"
 
#ifdef HAL_IWDG_MODULE_ENABLED
/* Private typedef -----------------------------------------------------------*/
/* Private define ------------------------------------------------------------*/
/* Status register needs up to 5 LSI clock periods divided by the clock
   prescaler to be updated. The number of LSI clock periods is upper-rounded to
   6 for the timeout value calculation.
   The timeout value is calculated using the highest prescaler (256) and
   the LSI_VALUE constant. The value of this constant can be changed by the user
   to take into account possible LSI clock period variations.
   The timeout value is multiplied by 1000 to be converted in milliseconds.
   LSI startup time is also considered here by adding LSI_STARTUP_TIME
   converted in milliseconds. */
#define HAL_IWDG_DEFAULT_TIMEOUT        (((6UL * 256UL * 1000UL) / LSI_VALUE) + ((LSI_STARTUP_TIME / 1000UL) + 1UL))
#define IWDG_KERNEL_UPDATE_FLAGS        (IWDG_SR_RVU | IWDG_SR_PVU)
/* Private macro -------------------------------------------------------------*/
/* Private variables ---------------------------------------------------------*/
/* Private function prototypes -----------------------------------------------*/
/* Exported functions --------------------------------------------------------*/
 
HAL_StatusTypeDef HAL_IWDG_Init(IWDG_HandleTypeDef *hiwdg)
{
  uint32_t tickstart;
 
  /* Check the IWDG handle allocation */
  if (hiwdg == NULL)
  {
    return HAL_ERROR;
  }
 
  /* Check the parameters */
  assert_param(IS_IWDG_ALL_INSTANCE(hiwdg->Instance));
  assert_param(IS_IWDG_PRESCALER(hiwdg->Init.Prescaler));
  assert_param(IS_IWDG_RELOAD(hiwdg->Init.Reload));
 
  /* Enable IWDG. LSI is turned on automatically */
  __HAL_IWDG_START(hiwdg);
 
  /* Enable write access to IWDG_PR and IWDG_RLR registers by writing
  0x5555 in KR */
  IWDG_ENABLE_WRITE_ACCESS(hiwdg);
 
  /* Write to IWDG registers the Prescaler & Reload values to work with */
  hiwdg->Instance->PR = hiwdg->Init.Prescaler;
  hiwdg->Instance->RLR = hiwdg->Init.Reload;
 
  /* Check pending flag, if previous update not done, return timeout */
  tickstart = HAL_GetTick();
 
  /* Wait for register to be updated */
  while ((hiwdg->Instance->SR & IWDG_KERNEL_UPDATE_FLAGS) != 0x00u)
  {
    if ((HAL_GetTick() - tickstart) > HAL_IWDG_DEFAULT_TIMEOUT)
    {
      if ((hiwdg->Instance->SR & IWDG_KERNEL_UPDATE_FLAGS) != 0x00u)
      {
        return HAL_TIMEOUT;
      }
    }
  }
 
  /* Reload IWDG counter with value defined in the reload register */
  __HAL_IWDG_RELOAD_COUNTER(hiwdg);
 
  /* Return function status */
  return HAL_OK;
}
 
 
HAL_StatusTypeDef HAL_IWDG_Refresh(IWDG_HandleTypeDef *hiwdg)
{
  /* Reload IWDG counter with value defined in the reload register */
  __HAL_IWDG_RELOAD_COUNTER(hiwdg);
 
  /* Return function status */
  return HAL_OK;
}
 
 
#endif /* HAL_IWDG_MODULE_ENABLED */