text: /**
    ******************************************************************************
    * @file    stm32f10x_wwdg.c
    * @author  MCD Application Team
    * @version V3.6.1
    * @date    05-March-2012
    * @brief   This file provides all the WWDG firmware functions.
    ******************************************************************************
    Released into the public domain.
    This work is free: you can redistribute it and/or modify it under the terms of
    Creative Commons Zero license v1.0
  
    This work is licensed under the Creative Commons Zero 1.0 United States License.
    To view a copy of this license, visit http://creativecommons.org/publicdomain/zero/1.0/
    or send a letter to Creative Commons, 171 Second Street, Suite 300, San Francisco,
    California, 94105, USA.
  
    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
    or FITNESS FOR A PARTICULAR PURPOSE.
    ******************************************************************************
    */
  
  /* Includes ------------------------------------------------------------------*/
  #include "stm32f10x_wwdg.h"
  #include "stm32f10x_rcc.h"
  
  /** @addtogroup STM32F10x_StdPeriph_Driver
    * @{
    */
  
  /** @defgroup WWDG
    * @brief WWDG driver modules
    * @{
    */
  
  /** @defgroup WWDG_Private_TypesDefinitions
    * @{
    */
  
  /**
    * @}
    */
  
  /** @defgroup WWDG_Private_Defines
    * @{
    */
  
  /* ----------- WWDG registers bit address in the alias region ----------- */
  #define WWDG_OFFSET       (WWDG_BASE - PERIPH_BASE)
  
  /* Alias word address of EWI bit */
  #define CFR_OFFSET        (WWDG_OFFSET + 0x04)
  #define EWI_BitNumber     0x09
  #define CFR_EWI_BB        (PERIPH_BB_BASE + (CFR_OFFSET * 32) + (EWI_BitNumber * 4))
  
  /* --------------------- WWDG registers bit mask ------------------------ */
  
  /* CR register bit mask */
  #define CR_WDGA_Set       ((uint32_t)0x00000080)
  
  /* CFR register bit mask */
  #define CFR_WDGTB_Mask    ((uint32_t)0xFFFFFE7F)
  #define CFR_W_Mask        ((uint32_t)0xFFFFFF80)
  #define BIT_Mask          ((uint8_t)0x7F)
  
  /**
    * @}
    */
  
  /** @defgroup WWDG_Private_Macros
    * @{
    */
  
  /**
    * @}
    */
  
  /** @defgroup WWDG_Private_Variables
    * @{
    */
  
  /**
    * @}
    */
  
  /** @defgroup WWDG_Private_FunctionPrototypes
    * @{
    */
  
  /**
    * @}
    */
  
  /** @defgroup WWDG_Private_Functions
    * @{
    */
  
  /**
    * @brief  Deinitializes the WWDG peripheral registers to their default reset values.
    * @param  None
    * @retval None
    */
  void WWDG_DeInit(void)
  {
    RCC_APB1PeriphResetCmd(RCC_APB1Periph_WWDG, ENABLE);
    RCC_APB1PeriphResetCmd(RCC_APB1Periph_WWDG, DISABLE);
  }
  
  /**
    * @brief  Sets the WWDG Prescaler.
    * @param  WWDG_Prescaler: specifies the WWDG Prescaler.
    *   This parameter can be one of the following values:
    *     @arg WWDG_Prescaler_1: WWDG counter clock = (PCLK1/4096)/1
    *     @arg WWDG_Prescaler_2: WWDG counter clock = (PCLK1/4096)/2
    *     @arg WWDG_Prescaler_4: WWDG counter clock = (PCLK1/4096)/4
    *     @arg WWDG_Prescaler_8: WWDG counter clock = (PCLK1/4096)/8
    * @retval None
    */
  void WWDG_SetPrescaler(uint32_t WWDG_Prescaler)
  {
    uint32_t tmpreg = 0;
    /* Check the parameters */
    assert_param(IS_WWDG_PRESCALER(WWDG_Prescaler));
    /* Clear WDGTB[1:0] bits */
    tmpreg = WWDG->CFR & CFR_WDGTB_Mask;
    /* Set WDGTB[1:0] bits according to WWDG_Prescaler value */
    tmpreg |= WWDG_Prescaler;
    /* Store the new value */
    WWDG->CFR = tmpreg;
  }
  
  /**
    * @brief  Sets the WWDG window value.
    * @param  WindowValue: specifies the window value to be compared to the downcounter.
    *   This parameter value must be lower than 0x80.
    * @retval None
    */
  void WWDG_SetWindowValue(uint8_t WindowValue)
  {
    __IO uint32_t tmpreg = 0;
  
    /* Check the parameters */
    assert_param(IS_WWDG_WINDOW_VALUE(WindowValue));
    /* Clear W[6:0] bits */
  
    tmpreg = WWDG->CFR & CFR_W_Mask;
  
    /* Set W[6:0] bits according to WindowValue value */
    tmpreg |= WindowValue & (uint32_t) BIT_Mask;
  
    /* Store the new value */
    WWDG->CFR = tmpreg;
  }
  
  /**
    * @brief  Enables the WWDG Early Wakeup interrupt(EWI).
    * @param  None
    * @retval None
    */
  void WWDG_EnableIT(void)
  {
    *(__IO uint32_t *) CFR_EWI_BB = (uint32_t)ENABLE;
  }
  
  /**
    * @brief  Sets the WWDG counter value.
    * @param  Counter: specifies the watchdog counter value.
    *   This parameter must be a number between 0x40 and 0x7F.
    * @retval None
    */
  void WWDG_SetCounter(uint8_t Counter)
  {
    /* Check the parameters */
    assert_param(IS_WWDG_COUNTER(Counter));
    /* Write to T[6:0] bits to configure the counter value, no need to do
       a read-modify-write; writing a 0 to WDGA bit does nothing */
    WWDG->CR = Counter & BIT_Mask;
  }
  
  /**
    * @brief  Enables WWDG and load the counter value.
    * @param  Counter: specifies the watchdog counter value.
    *   This parameter must be a number between 0x40 and 0x7F.
    * @retval None
    */
  void WWDG_Enable(uint8_t Counter)
  {
    /* Check the parameters */
    assert_param(IS_WWDG_COUNTER(Counter));
    WWDG->CR = CR_WDGA_Set | Counter;
  }
  
  /**
    * @brief  Checks whether the Early Wakeup interrupt flag is set or not.
    * @param  None
    * @retval The new state of the Early Wakeup interrupt flag (SET or RESET)
    */
  FlagStatus WWDG_GetFlagStatus(void)
  {
    return (FlagStatus)(WWDG->SR);
  }
  
  /**
    * @brief  Clears Early Wakeup interrupt flag.
    * @param  None
    * @retval None
    */
  void WWDG_ClearFlag(void)
  {
    WWDG->SR = (uint32_t)RESET;
  }
  
  /**
    * @}
    */
  
  /**
    * @}
    */
  
  /**
    * @}
    */
  
  