text: /**
    ******************************************************************************
    * @file    stm32f10x_exti.c
    * @author  MCD Application Team
    * @version V3.6.1
    * @date    05-March-2012
    * @brief   This file provides all the EXTI 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_exti.h"
  
  /** @addtogroup STM32F10x_StdPeriph_Driver
    * @{
    */
  
  /** @defgroup EXTI
    * @brief EXTI driver modules
    * @{
    */
  
  /** @defgroup EXTI_Private_TypesDefinitions
    * @{
    */
  
  /**
    * @}
    */
  
  /** @defgroup EXTI_Private_Defines
    * @{
    */
  
  #define EXTI_LINENONE    ((uint32_t)0x00000)  /* No interrupt selected */
  
  /**
    * @}
    */
  
  /** @defgroup EXTI_Private_Macros
    * @{
    */
  
  /**
    * @}
    */
  
  /** @defgroup EXTI_Private_Variables
    * @{
    */
  
  /**
    * @}
    */
  
  /** @defgroup EXTI_Private_FunctionPrototypes
    * @{
    */
  
  /**
    * @}
    */
  
  /** @defgroup EXTI_Private_Functions
    * @{
    */
  
  /**
    * @brief  Deinitializes the EXTI peripheral registers to their default reset values.
    * @param  None
    * @retval None
    */
  void EXTI_DeInit(void)
  {
    EXTI->IMR = 0x00000000;
    EXTI->EMR = 0x00000000;
    EXTI->RTSR = 0x00000000;
    EXTI->FTSR = 0x00000000;
    EXTI->PR = 0x000FFFFF;
  }
  
  /**
    * @brief  Initializes the EXTI peripheral according to the specified
    *         parameters in the EXTI_InitStruct.
    * @param  EXTI_InitStruct: pointer to a EXTI_InitTypeDef structure
    *         that contains the configuration information for the EXTI peripheral.
    * @retval None
    */
  void EXTI_Init(EXTI_InitTypeDef* EXTI_InitStruct)
  {
    uint32_t tmp = 0;
  
    /* Check the parameters */
    assert_param(IS_EXTI_MODE(EXTI_InitStruct->EXTI_Mode));
    assert_param(IS_EXTI_TRIGGER(EXTI_InitStruct->EXTI_Trigger));
    assert_param(IS_EXTI_LINE(EXTI_InitStruct->EXTI_Line));
    assert_param(IS_FUNCTIONAL_STATE(EXTI_InitStruct->EXTI_LineCmd));
  
    tmp = (uint32_t)EXTI_BASE;
  
    if (EXTI_InitStruct->EXTI_LineCmd != DISABLE)
    {
      /* Clear EXTI line configuration */
      EXTI->IMR &= ~EXTI_InitStruct->EXTI_Line;
      EXTI->EMR &= ~EXTI_InitStruct->EXTI_Line;
  
      tmp += EXTI_InitStruct->EXTI_Mode;
  
      *(__IO uint32_t *) tmp |= EXTI_InitStruct->EXTI_Line;
  
      /* Clear Rising Falling edge configuration */
      EXTI->RTSR &= ~EXTI_InitStruct->EXTI_Line;
      EXTI->FTSR &= ~EXTI_InitStruct->EXTI_Line;
  
      /* Select the trigger for the selected external interrupts */
      if (EXTI_InitStruct->EXTI_Trigger == EXTI_Trigger_Rising_Falling)
      {
        /* Rising Falling edge */
        EXTI->RTSR |= EXTI_InitStruct->EXTI_Line;
        EXTI->FTSR |= EXTI_InitStruct->EXTI_Line;
      }
      else
      {
        tmp = (uint32_t)EXTI_BASE;
        tmp += EXTI_InitStruct->EXTI_Trigger;
  
        *(__IO uint32_t *) tmp |= EXTI_InitStruct->EXTI_Line;
      }
    }
    else
    {
      tmp += EXTI_InitStruct->EXTI_Mode;
  
      /* Disable the selected external lines */
      *(__IO uint32_t *) tmp &= ~EXTI_InitStruct->EXTI_Line;
    }
  }
  
  /**
    * @brief  Fills each EXTI_InitStruct member with its reset value.
    * @param  EXTI_InitStruct: pointer to a EXTI_InitTypeDef structure which will
    *         be initialized.
    * @retval None
    */
  void EXTI_StructInit(EXTI_InitTypeDef* EXTI_InitStruct)
  {
    EXTI_InitStruct->EXTI_Line = EXTI_LINENONE;
    EXTI_InitStruct->EXTI_Mode = EXTI_Mode_Interrupt;
    EXTI_InitStruct->EXTI_Trigger = EXTI_Trigger_Falling;
    EXTI_InitStruct->EXTI_LineCmd = DISABLE;
  }
  
  /**
    * @brief  Generates a Software interrupt.
    * @param  EXTI_Line: specifies the EXTI lines to be enabled or disabled.
    *   This parameter can be any combination of EXTI_Linex where x can be (0..19).
    * @retval None
    */
  void EXTI_GenerateSWInterrupt(uint32_t EXTI_Line)
  {
    /* Check the parameters */
    assert_param(IS_EXTI_LINE(EXTI_Line));
  
    EXTI->SWIER |= EXTI_Line;
  }
  
  /**
    * @brief  Checks whether the specified EXTI line flag is set or not.
    * @param  EXTI_Line: specifies the EXTI line flag to check.
    *   This parameter can be:
    *     @arg EXTI_Linex: External interrupt line x where x(0..19)
    * @retval The new state of EXTI_Line (SET or RESET).
    */
  FlagStatus EXTI_GetFlagStatus(uint32_t EXTI_Line)
  {
    FlagStatus bitstatus = RESET;
    /* Check the parameters */
    assert_param(IS_GET_EXTI_LINE(EXTI_Line));
  
    if ((EXTI->PR & EXTI_Line) != (uint32_t)RESET)
    {
      bitstatus = SET;
    }
    else
    {
      bitstatus = RESET;
    }
    return bitstatus;
  }
  
  /**
    * @brief  Clears the EXTI's line pending flags.
    * @param  EXTI_Line: specifies the EXTI lines flags to clear.
    *   This parameter can be any combination of EXTI_Linex where x can be (0..19).
    * @retval None
    */
  void EXTI_ClearFlag(uint32_t EXTI_Line)
  {
    /* Check the parameters */
    assert_param(IS_EXTI_LINE(EXTI_Line));
  
    EXTI->PR = EXTI_Line;
  }
  
  /**
    * @brief  Checks whether the specified EXTI line is asserted or not.
    * @param  EXTI_Line: specifies the EXTI line to check.
    *   This parameter can be:
    *     @arg EXTI_Linex: External interrupt line x where x(0..19)
    * @retval The new state of EXTI_Line (SET or RESET).
    */
  ITStatus EXTI_GetITStatus(uint32_t EXTI_Line)
  {
    ITStatus bitstatus = RESET;
    uint32_t enablestatus = 0;
    /* Check the parameters */
    assert_param(IS_GET_EXTI_LINE(EXTI_Line));
  
    enablestatus =  EXTI->IMR & EXTI_Line;
    if (((EXTI->PR & EXTI_Line) != (uint32_t)RESET) && (enablestatus != (uint32_t)RESET))
    {
      bitstatus = SET;
    }
    else
    {
      bitstatus = RESET;
    }
    return bitstatus;
  }
  
  /**
    * @brief  Clears the EXTI's line pending bits.
    * @param  EXTI_Line: specifies the EXTI lines to clear.
    *   This parameter can be any combination of EXTI_Linex where x can be (0..19).
    * @retval None
    */
  void EXTI_ClearITPendingBit(uint32_t EXTI_Line)
  {
    /* Check the parameters */
    assert_param(IS_EXTI_LINE(EXTI_Line));
  
    EXTI->PR = EXTI_Line;
  }
  
  /**
    * @}
    */
  
  /**
    * @}
    */
  
  /**
    * @}
    */
  
  
  