stm32l4xx_hal_iwdg.c

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/* Includes ------------------------------------------------------------------*/
#include "stm32l4xx_hal.h"

#ifdef HAL_IWDG_MODULE_ENABLED

/* Private typedef -----------------------------------------------------------*/
/* Private define ------------------------------------------------------------*/
/* Status register need 5 RC LSI divided by prescaler clock to be updated. With
   higher prescaler (256), and according to LSI variation, we need to wait at
   least 6 cycles so 48 ms. */
#define HAL_IWDG_DEFAULT_TIMEOUT            48u

/* 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));
  assert_param(IS_IWDG_WINDOW(hiwdg->Init.Window));

  /* Enable IWDG. LSI is turned on automaticaly */
  __HAL_IWDG_START(hiwdg);

  /* Enable write access to IWDG_PR, IWDG_RLR and IWDG_WINR 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 != 0x00u)
  {
    if ((HAL_GetTick() - tickstart) > HAL_IWDG_DEFAULT_TIMEOUT)
    {
      return HAL_TIMEOUT;
    }
  }

  /* If window parameter is different than current value, modify window
  register */
  if (hiwdg->Instance->WINR != hiwdg->Init.Window)
  {
    /* Write to IWDG WINR the IWDG_Window value to compare with. In any case,
    even if window feature is disabled, Watchdog will be reloaded by writing
    windows register */
    hiwdg->Instance->WINR = hiwdg->Init.Window;
  }
  else
  {
    /* 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 */

/************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/