File content as of revision 205:c41fc65bcfb4:

/**
  ******************************************************************************
  * @file    stm32f0xx_hal_wwdg.c
  * @author  MCD Application Team
  * @version V1.0.0
  * @date    20-May-2014
  * @brief   WWDG HAL module driver.
  *
  *          This file provides firmware functions to manage the following 
  *          functionalities of the Window Watchdog (WWDG) peripheral:
  *           + Initialization/de-initialization function
  *           + I/O operation function
  *           + Peripheral State function
  *         
  @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 (downcounter) 
      before reaching 0x3F value (i.e. a reset is generated when the counter
      value rolls over 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.
      (+) 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 = PCLK1 /(4096 * Prescaler)
          WWDG timeout = (WWDG clock) * (counter value) 
      (+) 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

      (+) Min-max timeout value @24 MHz(PCLK1): ~1.36 ms / ~87.4 ms
   
            ##### How to use this driver #####
  ==============================================================================
           [..]
      (+) Enable WWDG APB1 clock using __WWDG_CLK_ENABLE().
      (+) Set the WWDG prescaler, refresh window and counter value 
          using HAL_WWDG_Init() function.
      (+) Start the WWDG using HAL_WWDG_Start() function.
          When the WWDG is enabled the counter value should be configured to 
          a value greater than 0x40 to prevent generating an immediate reset.
      (+) Optionally you can enable the Early Wakeup Interrupt (EWI) which is 
          generated when the counter reaches 0x40, and then start the WWDG using
          HAL_WWDG_Start_IT().
          Once enabled, EWI interrupt cannot be disabled except by a system reset.          
      (+) 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.
  
  @endverbatim
  ******************************************************************************
  * @attention
  *
  * <h2><center>&copy; COPYRIGHT(c) 2014 STMicroelectronics</center></h2>
  *
  * Redistribution and use in source and binary forms, with or without modification,
  * are permitted provided that the following conditions are met:
  *   1. Redistributions of source code must retain the above copyright notice,
  *      this list of conditions and the following disclaimer.
  *   2. Redistributions in binary form must reproduce the above copyright notice,
  *      this list of conditions and the following disclaimer in the documentation
  *      and/or other materials provided with the distribution.
  *   3. Neither the name of STMicroelectronics nor the names of its contributors
  *      may be used to endorse or promote products derived from this software
  *      without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *
  ******************************************************************************  
  */ 

/* Includes ------------------------------------------------------------------*/
#include "stm32f0xx_hal.h"

/** @addtogroup STM32F0xx_HAL_Driver
  * @{
  */

/** @defgroup WWDG 
  * @brief WWDG HAL module driver.
  * @{
  */

#ifdef HAL_WWDG_MODULE_ENABLED

/* Private typedef -----------------------------------------------------------*/
/* Private define ------------------------------------------------------------*/
/* Private macro -------------------------------------------------------------*/
/* Private variables ---------------------------------------------------------*/
/* Private function prototypes -----------------------------------------------*/
/* Private functions ---------------------------------------------------------*/

/** @defgroup WWDG_Private_Functions
  * @{
  */

/** @defgroup HAL_WWDG_Group1 Initialization/de-initialization function 
 *  @brief    Initialization and Configuration functions. 
 *
@verbatim    
 ===============================================================================
              ##### Initialization/de-initialization function #####
 ===============================================================================
    [..]  This section provides functions allowing to:
      (+) Initialize the WWDG according to the specified parameters 
          in the WWDG_InitTypeDef and create the associated handle
      (+) DeInitialize the WWDG peripheral
      (+) Initialize the WWDG MSP
      (+) DeInitialize the WWDG MSP 
 
@endverbatim
  * @{
  */

/**
  * @brief  Initializes the WWDG according to the specified
  *         parameters in the WWDG_InitTypeDef and creates the associated handle.
  * @param  hwwdg: WWDG handle
  * @retval HAL status
  */
HAL_StatusTypeDef HAL_WWDG_Init(WWDG_HandleTypeDef *hwwdg)
{ 
  uint32_t tmp = 0;

  /* 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)); 
  
  if(hwwdg->State == HAL_WWDG_STATE_RESET)
  {
    /* Init the low level hardware */
    HAL_WWDG_MspInit(hwwdg);
  }
  
  /* Change WWDG peripheral state */
  hwwdg->State = HAL_WWDG_STATE_BUSY;
  
  /* Set WWDG Prescaler and Window */
  /* Get the CFR register value */
  tmp = hwwdg->Instance->CFR;
  
  /* Clear WDGTB[1:0] and W[6:0] bits */
  tmp &= ((uint32_t)~(WWDG_CFR_WDGTB | WWDG_CFR_W));
  
  /* Prepare the WWDG Prescaler and Window parameters */
  tmp |= hwwdg->Init.Prescaler | hwwdg->Init.Window;
  
  /* Write to WWDG CFR */
  hwwdg->Instance->CFR = tmp;   
 
  /* Set WWDG Counter */
  /* Get the CR register value */
  tmp = hwwdg->Instance->CR;
  
  /* Clear T[6:0] bits */
  tmp &= ((uint32_t)~(WWDG_CR_T));
  
  /* Prepare the WWDG Counter parameter */
  tmp |= (hwwdg->Init.Counter);  
  
  /* Write to WWDG CR */
  hwwdg->Instance->CR = tmp;  
   
  /* Change WWDG peripheral state */
  hwwdg->State = HAL_WWDG_STATE_READY;
  
  /* Return function status */
  return HAL_OK;
}

/**
  * @brief  DeInitializes the WWDG peripheral. 
  * @param  hwwdg: WWDG handle
  * @retval HAL status
  */
HAL_StatusTypeDef HAL_WWDG_DeInit(WWDG_HandleTypeDef *hwwdg)
{
  /* Check the parameters */
  assert_param(IS_WWDG_ALL_INSTANCE(hwwdg->Instance));

  /* Change WWDG peripheral state */  
  hwwdg->State = HAL_WWDG_STATE_BUSY;

  /* DeInit the low level hardware */
  HAL_WWDG_MspDeInit(hwwdg);
  
  /* Reset WWDG Control register */
  hwwdg->Instance->CR  = (uint32_t)0x0000007F;
    
  /* Reset WWDG Configuration register */
  hwwdg->Instance->CFR = (uint32_t)0x0000007F;
  
  /* Reset WWDG Status register */
  hwwdg->Instance->SR  = 0; 
  
  /* Change WWDG peripheral state */    
  hwwdg->State = HAL_WWDG_STATE_RESET; 

  /* Return function status */
  return HAL_OK;
}

/**
  * @brief  Initializes the WWDG MSP.
  * @param  hwwdg: WWDG handle
  * @retval None
  */
__weak void HAL_WWDG_MspInit(WWDG_HandleTypeDef *hwwdg)
{
  /* NOTE : This function Should not be modified, when the callback is needed,
            the HAL_WWDG_MspInit could be implemented in the user file
   */
}

/**
  * @brief  DeInitializes the WWDG MSP.
  * @param  hwwdg: WWDG handle
  * @retval None
  */
__weak void HAL_WWDG_MspDeInit(WWDG_HandleTypeDef *hwwdg)
{
  /* NOTE : This function Should not be modified, when the callback is needed,
            the HAL_WWDG_MspDeInit could be implemented in the user file
   */
}

/**
  * @brief  Early Wakeup WWDG callback.
  * @param  hwwdg: WWDG handle
  * @retval None
  */
__weak void HAL_WWDG_WakeupCallback(WWDG_HandleTypeDef* hwwdg)
{
  /* NOTE : This function Should not be modified, when the callback is needed,
            the HAL_WWDG_WakeupCallback could be implemented in the user file
   */
}

/**
  * @}
  */

/** @defgroup HAL_WWDG_Group2 I/O operation function 
 *  @brief    I/O operation function 
 *
@verbatim   
 ===============================================================================
                      ##### IO operation function #####
 ===============================================================================  
    [..]  This section provides functions allowing to:
      (+) Start the WWDG.
      (+) Refresh the WWDG.
      (+) Handle WWDG interrupt request. 

@endverbatim
  * @{
  */

/**
  * @brief  Starts the WWDG
  * @param  hwwdg: WWDG handle
  * @retval HAL status
  */
HAL_StatusTypeDef HAL_WWDG_Start(WWDG_HandleTypeDef *hwwdg)
{
  /* Process locked */
  __HAL_LOCK(hwwdg); 
  
  /* Change WWDG peripheral state */  
  hwwdg->State = HAL_WWDG_STATE_BUSY;
                  
  /* Enable the Peripheral */
  __HAL_WWDG_ENABLE(hwwdg);  

  /* Change WWDG peripheral state */    
  hwwdg->State = HAL_WWDG_STATE_READY; 
                  
  /* Process unlocked */
  __HAL_UNLOCK(hwwdg);
  
  /* Return function status */
  return HAL_OK;
}

/**
  * @brief  Starts the WWDG with interrupt enabled.
  * @param  hwwdg: WWDG handle
  * @retval HAL status
  */
HAL_StatusTypeDef HAL_WWDG_Start_IT(WWDG_HandleTypeDef *hwwdg)
{
  /* Process locked */
  __HAL_LOCK(hwwdg); 
  
  /* Change WWDG peripheral state */  
  hwwdg->State = HAL_WWDG_STATE_BUSY;

  /* Enable the Early Wakeup Interrupt */ 
  __HAL_WWDG_ENABLE_IT(WWDG_IT_EWI);
                  
  /* Enable the Peripheral */
  __HAL_WWDG_ENABLE(hwwdg);  
  
  /* Return function status */
  return HAL_OK;
}

/**
  * @brief  Refreshes the WWDG.
  * @param  hwwdg: WWDG handle
  * @param  Counter: Counter value to refresh WWDG with
  * @retval HAL status
  */
HAL_StatusTypeDef HAL_WWDG_Refresh(WWDG_HandleTypeDef *hwwdg, uint32_t Counter)
{
    /* Process locked */
  __HAL_LOCK(hwwdg); 

  /* Change WWDG peripheral state */  
  hwwdg->State = HAL_WWDG_STATE_BUSY;

  /* Check the parameters */
  assert_param(IS_WWDG_COUNTER(Counter));

  /* Write to WWDG CR the WWDG Counter value to refresh with */
  MODIFY_REG(hwwdg->Instance->CR, WWDG_CR_T, Counter);
  
  /* Change WWDG peripheral state */    
  hwwdg->State = HAL_WWDG_STATE_READY; 
                  
  /* Process unlocked */
  __HAL_UNLOCK(hwwdg);
  
  /* Return function status */
  return HAL_OK;
}

/**
  * @brief  Handles 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 using __HAL_WWDG_ENABLE_IT() macro.
  *         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: WWDG handle
  * @retval None
  */
void HAL_WWDG_IRQHandler(WWDG_HandleTypeDef *hwwdg)
{
  /* WWDG Early Wakeup Interrupt occurred */   
  if(__HAL_WWDG_GET_FLAG(hwwdg, WWDG_FLAG_EWIF) != RESET)
  {
    /* Early Wakeup callback */ 
    HAL_WWDG_WakeupCallback(hwwdg);
  
    /* Change WWDG peripheral state */
    hwwdg->State = HAL_WWDG_STATE_READY; 
                  
    /* Clear the WWDG Data Ready flag */
    __HAL_WWDG_CLEAR_FLAG(hwwdg, WWDG_FLAG_EWIF);
  
    /* Process unlocked */
    __HAL_UNLOCK(hwwdg);
}
  }

/**
  * @}
  */

/** @defgroup HAL_WWDG_Group3 Peripheral State function 
 *  @brief    Peripheral State functions. 
 *
@verbatim   
 ===============================================================================
                      ##### Peripheral State function #####
 ===============================================================================  
    [..]
    This subsection permits to get in run-time the status of the peripheral 
    and the data flow.

@endverbatim
  * @{
  */

/**
  * @brief  Returns the WWDG state.
  * @param  hwwdg: WWDG handle
  * @retval HAL state
  */
HAL_WWDG_StateTypeDef HAL_WWDG_GetState(WWDG_HandleTypeDef *hwwdg)
{
  return hwwdg->State;
}
/**
  * @}
  */

/**
  * @}
  */

#endif /* HAL_WWDG_MODULE_ENABLED */
/**
  * @}
  */

/**
  * @}
  */

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