text: /**
    ******************************************************************************
    * @file    stm32g0xx_hal_wwdg.c
    * @author  MCD Application Team
    * @brief   WWDG HAL module driver.
    *          This file provides firmware functions to manage the following
    *          functionalities of the Window Watchdog (WWDG) peripheral:
    *           + Initialization and Configuration functions
    *           + IO operation functions
    ******************************************************************************
    * @attention
    *
    * Copyright (c) 2018 STMicroelectronics.
    * All rights reserved.
    *
    * This software is licensed under terms that can be found in the LICENSE file
    * in the root directory of this software component.
    * If no LICENSE file comes with this software, it is provided AS-IS.
    *
    ******************************************************************************
    @verbatim
    ==============================================================================
                        ##### WWDG Specific features #####
    ==============================================================================
    [..]
      Once enabled the WWDG generates a system reset on expiry of a programmed
      time period, unless the program refreshes the counter (T[6;0] downcounter)
      before reaching 0x3F value (i.e. a reset is generated when the counter
      value rolls down from 0x40 to 0x3F).
  
      (+) An MCU reset is also generated if the counter value is refreshed
          before the counter has reached the refresh window value. This
          implies that the counter must be refreshed in a limited window.
      (+) Once enabled the WWDG cannot be disabled except by a system reset.
      (+) If required by application, an Early Wakeup Interrupt can be triggered
          in order to be warned before WWDG expiration. The Early Wakeup Interrupt
          (EWI) can be used if specific safety operations or data logging must
          be performed before the actual reset is generated. When the downcounter
          reaches 0x40, interrupt occurs. This mechanism requires WWDG interrupt
          line to be enabled in NVIC. Once enabled, EWI interrupt cannot be
          disabled except by a system reset.
      (+) WWDGRST flag in RCC CSR register can be used to inform when a WWDG
          reset occurs.
      (+) The WWDG counter input clock is derived from the APB clock divided
          by a programmable prescaler.
      (+) WWDG clock (Hz) = PCLK1 / (4096 * Prescaler)
      (+) WWDG timeout (mS) = 1000 * (T[5;0] + 1) / WWDG clock (Hz)
          where T[5;0] are the lowest 6 bits of Counter.
      (+) WWDG Counter refresh is allowed between the following limits :
          (++) min time (mS) = 1000 * (Counter - Window) / WWDG clock
          (++) max time (mS) = 1000 * (Counter - 0x40) / WWDG clock
      (+) Typical values:
          (++) Counter min (T[5;0] = 0x00) at 64 MHz (PCLK1) with zero prescaler:
               max timeout before reset: approximately 64us
          (++) Counter max (T[5;0] = 0x3F) at 64 MHz (PCLK1) with prescaler
               dividing by 128:
               max timeout before reset: approximately 524.28ms
  
                       ##### How to use this driver #####
    ==============================================================================
  
      *** Common driver usage ***
      ===========================
  
    [..]
      (+) Enable WWDG APB1 clock using __HAL_RCC_WWDG_CLK_ENABLE().
      (+) Configure the WWDG prescaler, refresh window value, counter value and early
          interrupt status using HAL_WWDG_Init() function. This will automatically
          enable WWDG and start its downcounter. Time reference can be taken from
          function exit. Care must be taken to provide a counter value
          greater than 0x40 to prevent generation of immediate reset.
      (+) If the Early Wakeup Interrupt (EWI) feature is enabled, an interrupt is
          generated when the counter reaches 0x40. When HAL_WWDG_IRQHandler is
          triggered by the interrupt service routine, flag will be automatically
          cleared and HAL_WWDG_WakeupCallback user callback will be executed. User
          can add his own code by customization of callback HAL_WWDG_WakeupCallback.
      (+) Then the application program must refresh the WWDG counter at regular
          intervals during normal operation to prevent an MCU reset, using
          HAL_WWDG_Refresh() function. This operation must occur only when
          the counter is lower than the refresh window value already programmed.
  
      *** Callback registration ***
      =============================
  
    [..]
      The compilation define USE_HAL_WWDG_REGISTER_CALLBACKS when set to 1 allows
      the user to configure dynamically the driver callbacks. Use Functions
      HAL_WWDG_RegisterCallback() to register a user callback.
  
      (+) Function HAL_WWDG_RegisterCallback() allows to register following
          callbacks:
          (++) EwiCallback : callback for Early WakeUp Interrupt.
          (++) MspInitCallback : WWDG MspInit.
      This function takes as parameters the HAL peripheral handle, the Callback ID
      and a pointer to the user callback function.
  
      (+) Use function HAL_WWDG_UnRegisterCallback() to reset a callback to
      the default weak (surcharged) function. HAL_WWDG_UnRegisterCallback()
      takes as parameters the HAL peripheral handle and the Callback ID.
      This function allows to reset following callbacks:
          (++) EwiCallback : callback for  Early WakeUp Interrupt.
          (++) MspInitCallback : WWDG MspInit.
  
      [..]
      When calling HAL_WWDG_Init function, callbacks are reset to the
      corresponding legacy weak (surcharged) functions:
      HAL_WWDG_EarlyWakeupCallback() and HAL_WWDG_MspInit() only if they have
      not been registered before.
  
      [..]
      When compilation define USE_HAL_WWDG_REGISTER_CALLBACKS is set to 0 or
      not defined, the callback registering feature is not available
      and weak (surcharged) callbacks are used.
  
      *** WWDG HAL driver macros list ***
      ===================================
      [..]
        Below the list of available macros in WWDG HAL driver.
        (+) __HAL_WWDG_ENABLE: Enable the WWDG peripheral
        (+) __HAL_WWDG_GET_FLAG: Get the selected WWDG's flag status
        (+) __HAL_WWDG_CLEAR_FLAG: Clear the WWDG's pending flags
        (+) __HAL_WWDG_ENABLE_IT: Enable the WWDG early wakeup interrupt
  
    @endverbatim
    ******************************************************************************
    */
  
  /* Includes ------------------------------------------------------------------*/
  #include "stm32g0xx_hal.h"
  
  /** @addtogroup STM32G0xx_HAL_Driver
    * @{
    */
  
  #ifdef HAL_WWDG_MODULE_ENABLED
  /** @defgroup WWDG WWDG
    * @brief WWDG HAL module driver.
    * @{
    */
  
  /* Private typedef -----------------------------------------------------------*/
  /* Private define ------------------------------------------------------------*/
  /* Private macro -------------------------------------------------------------*/
  /* Private variables ---------------------------------------------------------*/
  /* Private function prototypes -----------------------------------------------*/
  /* Exported functions --------------------------------------------------------*/
  
  /** @defgroup WWDG_Exported_Functions WWDG Exported Functions
    * @{
    */
  
  /** @defgroup WWDG_Exported_Functions_Group1 Initialization and Configuration functions
    *  @brief    Initialization and Configuration functions.
    *
  @verbatim
    ==============================================================================
            ##### Initialization and Configuration functions #####
    ==============================================================================
    [..]
      This section provides functions allowing to:
        (+) Initialize and start the WWDG according to the specified parameters
            in the WWDG_InitTypeDef of associated handle.
        (+) Initialize the WWDG MSP.
  
  @endverbatim
    * @{
    */
  
  /**
    * @brief  Initialize the WWDG according to the specified.
    *         parameters in the WWDG_InitTypeDef of  associated handle.
    * @param  hwwdg  pointer to a WWDG_HandleTypeDef structure that contains
    *                the configuration information for the specified WWDG module.
    * @retval HAL status
    */
  HAL_StatusTypeDef HAL_WWDG_Init(WWDG_HandleTypeDef *hwwdg)
  {
    /* Check the WWDG handle allocation */
    if (hwwdg == NULL)
    {
      return HAL_ERROR;
    }
  
    /* Check the parameters */
    assert_param(IS_WWDG_ALL_INSTANCE(hwwdg->Instance));
    assert_param(IS_WWDG_PRESCALER(hwwdg->Init.Prescaler));
    assert_param(IS_WWDG_WINDOW(hwwdg->Init.Window));
    assert_param(IS_WWDG_COUNTER(hwwdg->Init.Counter));
    assert_param(IS_WWDG_EWI_MODE(hwwdg->Init.EWIMode));
  
  #if (USE_HAL_WWDG_REGISTER_CALLBACKS == 1)
    /* Reset Callback pointers */
    if (hwwdg->EwiCallback == NULL)
    {
      hwwdg->EwiCallback = HAL_WWDG_EarlyWakeupCallback;
    }
  
    if (hwwdg->MspInitCallback == NULL)
    {
      hwwdg->MspInitCallback = HAL_WWDG_MspInit;
    }
  
    /* Init the low level hardware */
    hwwdg->MspInitCallback(hwwdg);
  #else
    /* Init the low level hardware */
    HAL_WWDG_MspInit(hwwdg);
  #endif /* USE_HAL_WWDG_REGISTER_CALLBACKS */
  
    /* Set WWDG Counter */
    WRITE_REG(hwwdg->Instance->CR, (WWDG_CR_WDGA | hwwdg->Init.Counter));
  
    /* Set WWDG Prescaler and Window */
    WRITE_REG(hwwdg->Instance->CFR, (hwwdg->Init.EWIMode | hwwdg->Init.Prescaler | hwwdg->Init.Window));
  
    /* Return function status */
    return HAL_OK;
  }
  
  
  /**
    * @brief  Initialize the WWDG MSP.
    * @param  hwwdg  pointer to a WWDG_HandleTypeDef structure that contains
    *                the configuration information for the specified WWDG module.
    * @note   When rewriting this function in user file, mechanism may be added
    *         to avoid multiple initialize when HAL_WWDG_Init function is called
    *         again to change parameters.
    * @retval None
    */
  __weak void HAL_WWDG_MspInit(WWDG_HandleTypeDef *hwwdg)
  {
    /* Prevent unused argument(s) compilation warning */
    UNUSED(hwwdg);
  
    /* NOTE: This function should not be modified, when the callback is needed,
             the HAL_WWDG_MspInit could be implemented in the user file
     */
  }
  
  
  #if (USE_HAL_WWDG_REGISTER_CALLBACKS == 1)
  /**
    * @brief  Register a User WWDG Callback
    *         To be used instead of the weak (surcharged) predefined callback
    * @param  hwwdg WWDG handle
    * @param  CallbackID ID of the callback to be registered
    *         This parameter can be one of the following values:
    *           @arg @ref HAL_WWDG_EWI_CB_ID Early WakeUp Interrupt Callback ID
    *           @arg @ref HAL_WWDG_MSPINIT_CB_ID MspInit callback ID
    * @param  pCallback pointer to the Callback function
    * @retval status
    */
  HAL_StatusTypeDef HAL_WWDG_RegisterCallback(WWDG_HandleTypeDef *hwwdg, HAL_WWDG_CallbackIDTypeDef CallbackID,
                                              pWWDG_CallbackTypeDef pCallback)
  {
    HAL_StatusTypeDef status = HAL_OK;
  
    if (pCallback == NULL)
    {
      status = HAL_ERROR;
    }
    else
    {
      switch (CallbackID)
      {
        case HAL_WWDG_EWI_CB_ID:
          hwwdg->EwiCallback = pCallback;
          break;
  
        case HAL_WWDG_MSPINIT_CB_ID:
          hwwdg->MspInitCallback = pCallback;
          break;
  
        default:
          status = HAL_ERROR;
          break;
      }
    }
  
    return status;
  }
  
  
  /**
    * @brief  Unregister a WWDG Callback
    *         WWDG Callback is redirected to the weak (surcharged) predefined callback
    * @param  hwwdg WWDG handle
    * @param  CallbackID ID of the callback to be registered
    *         This parameter can be one of the following values:
    *           @arg @ref HAL_WWDG_EWI_CB_ID Early WakeUp Interrupt Callback ID
    *           @arg @ref HAL_WWDG_MSPINIT_CB_ID MspInit callback ID
    * @retval status
    */
  HAL_StatusTypeDef HAL_WWDG_UnRegisterCallback(WWDG_HandleTypeDef *hwwdg, HAL_WWDG_CallbackIDTypeDef CallbackID)
  {
    HAL_StatusTypeDef status = HAL_OK;
  
    switch (CallbackID)
    {
      case HAL_WWDG_EWI_CB_ID:
        hwwdg->EwiCallback = HAL_WWDG_EarlyWakeupCallback;
        break;
  
      case HAL_WWDG_MSPINIT_CB_ID:
        hwwdg->MspInitCallback = HAL_WWDG_MspInit;
        break;
  
      default:
        status = HAL_ERROR;
        break;
    }
  
    return status;
  }
  #endif /* USE_HAL_WWDG_REGISTER_CALLBACKS */
  
  /**
    * @}
    */
  
  /** @defgroup WWDG_Exported_Functions_Group2 IO operation functions
    *  @brief    IO operation functions
    *
  @verbatim
    ==============================================================================
                        ##### IO operation functions #####
    ==============================================================================
    [..]
      This section provides functions allowing to:
      (+) Refresh the WWDG.
      (+) Handle WWDG interrupt request and associated function callback.
  
  @endverbatim
    * @{
    */
  
  /**
    * @brief  Refresh the WWDG.
    * @param  hwwdg  pointer to a WWDG_HandleTypeDef structure that contains
    *                the configuration information for the specified WWDG module.
    * @retval HAL status
    */
  HAL_StatusTypeDef HAL_WWDG_Refresh(WWDG_HandleTypeDef *hwwdg)
  {
    /* Write to WWDG CR the WWDG Counter value to refresh with */
    WRITE_REG(hwwdg->Instance->CR, (hwwdg->Init.Counter));
  
    /* Return function status */
    return HAL_OK;
  }
  
  /**
    * @brief  Handle WWDG interrupt request.
    * @note   The Early Wakeup Interrupt (EWI) can be used if specific safety operations
    *         or data logging must be performed before the actual reset is generated.
    *         The EWI interrupt is enabled by calling HAL_WWDG_Init function with
    *         EWIMode set to WWDG_EWI_ENABLE.
    *         When the downcounter reaches the value 0x40, and EWI interrupt is
    *         generated and the corresponding Interrupt Service Routine (ISR) can
    *         be used to trigger specific actions (such as communications or data
    *         logging), before resetting the device.
    * @param  hwwdg  pointer to a WWDG_HandleTypeDef structure that contains
    *                the configuration information for the specified WWDG module.
    * @retval None
    */
  void HAL_WWDG_IRQHandler(WWDG_HandleTypeDef *hwwdg)
  {
    /* Check if Early Wakeup Interrupt is enable */
    if (__HAL_WWDG_GET_IT_SOURCE(hwwdg, WWDG_IT_EWI) != RESET)
    {
      /* Check if WWDG Early Wakeup Interrupt occurred */
      if (__HAL_WWDG_GET_FLAG(hwwdg, WWDG_FLAG_EWIF) != RESET)
      {
        /* Clear the WWDG Early Wakeup flag */
        __HAL_WWDG_CLEAR_FLAG(hwwdg, WWDG_FLAG_EWIF);
  
  #if (USE_HAL_WWDG_REGISTER_CALLBACKS == 1)
        /* Early Wakeup registered callback */
        hwwdg->EwiCallback(hwwdg);
  #else
        /* Early Wakeup callback */
        HAL_WWDG_EarlyWakeupCallback(hwwdg);
  #endif /* USE_HAL_WWDG_REGISTER_CALLBACKS */
      }
    }
  }
  
  
  /**
    * @brief  WWDG Early Wakeup callback.
    * @param  hwwdg  pointer to a WWDG_HandleTypeDef structure that contains
    *                the configuration information for the specified WWDG module.
    * @retval None
    */
  __weak void HAL_WWDG_EarlyWakeupCallback(WWDG_HandleTypeDef *hwwdg)
  {
    /* Prevent unused argument(s) compilation warning */
    UNUSED(hwwdg);
  
    /* NOTE: This function should not be modified, when the callback is needed,
             the HAL_WWDG_EarlyWakeupCallback could be implemented in the user file
     */
  }
  
  /**
    * @}
    */
  
  /**
    * @}
    */
  
  #endif /* HAL_WWDG_MODULE_ENABLED */
  /**
    * @}
    */
  
  /**
    * @}
    */
  