/**
  ******************************************************************************
  * @file    stm32l1xx_exti.c
  * @author  MCD Application Team
  * @version V1.0.0
  * @date    31-December-2010
  * @brief   This file provides firmware functions to manage the following 
  *          functionalities of the EXTI peripheral:           
  *           - Initialization and Configuration
  *           - Interrupts and flags management
  *
  *  @verbatim  
  *  
  *          ===================================================================
  *                                     EXTI features
  *          ===================================================================
  *    
  *          External interrupt/event lines are mapped as following:
  *            1- All available GPIO pins are connected to the 16 external 
  *               interrupt/event lines from EXTI0 to EXTI15.
  *            2- EXTI line 16 is connected to the PVD output
  *            3- EXTI line 17 is connected to the RTC Alarm event
  *            4- EXTI line 18 is connected to the USB Device FS wakeup event
  *            5- EXTI line 19 is connected to the RTC Tamper and TimeStamp events
  *            6- EXTI line 20 is connected to the RTC Wakeup event
  *            7- EXTI line 21 is connected to the Comparator 1 wakeup event 
  *            8- EXTI line 22 is connected to the Comparator 2 wakeup event
  *
  *          ===================================================================
  *                                 How to use this driver
  *          ===================================================================  
  *              
  *          In order to use an I/O pin as an external interrupt source, follow
  *          steps below:
  *            1- Configure the I/O in input mode using GPIO_Init()
  *            2- Select the input source pin for the EXTI line using 
  *               SYSCFG_EXTILineConfig()
  *            3- Select the mode(interrupt, event) and configure the trigger 
  *               selection (Rising, falling or both) using EXTI_Init()
  *            4- Configure NVIC IRQ channel mapped to the EXTI line using NVIC_Init()
  *   
  *@note     SYSCFG APB clock must be enabled to get write access to SYSCFG_EXTICRx
  *          registers using RCC_APB2PeriphClockCmd(RCC_APB2Periph_SYSCFG, ENABLE);
  *          
  *  @endverbatim                  
  *
  ******************************************************************************
  * @attention
  *
  * THE PRESENT FIRMWARE WHICH IS FOR GUIDANCE ONLY AIMS AT PROVIDING CUSTOMERS
  * WITH CODING INFORMATION REGARDING THEIR PRODUCTS IN ORDER FOR THEM TO SAVE
  * TIME. AS A RESULT, STMICROELECTRONICS SHALL NOT BE HELD LIABLE FOR ANY
  * DIRECT, INDIRECT OR CONSEQUENTIAL DAMAGES WITH RESPECT TO ANY CLAIMS ARISING
  * FROM THE CONTENT OF SUCH FIRMWARE AND/OR THE USE MADE BY CUSTOMERS OF THE
  * CODING INFORMATION CONTAINED HEREIN IN CONNECTION WITH THEIR PRODUCTS.
  *
  * <h2><center>&copy; COPYRIGHT 2010 STMicroelectronics</center></h2>
  ******************************************************************************  
  */ 

/* Includes ------------------------------------------------------------------*/
#include "stm32l1xx_exti.h"

/** @addtogroup STM32L1xx_StdPeriph_Driver
  * @{
  */

/** @defgroup EXTI 
  * @brief EXTI driver modules
  * @{
  */

/* Private typedef -----------------------------------------------------------*/
/* Private define ------------------------------------------------------------*/
#define EXTI_LINENONE    ((uint32_t)0x00000)  /* No interrupt selected */

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

/** @defgroup EXTI_Private_Functions
  * @{
  */

/** @defgroup EXTI_Group1 Initialization and Configuration functions
 *  @brief   Initialization and Configuration functions 
 *
@verbatim   
 ===============================================================================
                  Initialization and Configuration functions
 ===============================================================================  

@endverbatim
  * @{
  */

/**
  * @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 = 0x007FFFFF;
}

/**
  * @brief  Initializes the EXTI peripheral according to the specified
  *   parameters in the EXTI_InitStruct.
  *    EXTI_Line specifies the EXTI line (EXTI0....EXTI22)  
  *    EXTI_Mode specifies which EXTI line is used as interrupt or an event
  *    EXTI_Trigger selects the trigger. When the trigger occurs, interrupt
  *                 pending bit will be set
  *    EXTI_LineCmd controls (Enable/Disable) the EXTI line
  * @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 on selected EXTI line.
  * @param  EXTI_Line: specifies the EXTI line on which the software interrupt
  *         will be generated.
  *   This parameter can be any combination of EXTI_Linex where x can be (0..22).
  * @retval None
  */
void EXTI_GenerateSWInterrupt(uint32_t EXTI_Line)
{
  /* Check the parameters */
  assert_param(IS_EXTI_LINE(EXTI_Line));
  
  EXTI->SWIER |= EXTI_Line;
}

/**
  * @}
  */

/** @defgroup EXTI_Group2 Interrupts and flags management functions
 *  @brief   Interrupts and flags management functions 
 *
@verbatim   
 ===============================================================================
                  Interrupts and flags management functions
 ===============================================================================  

@endverbatim
  * @{
  */

/**
  * @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..22)
  * @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..22).
  * @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..22)
  * @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..22).
  * @retval None
  */
void EXTI_ClearITPendingBit(uint32_t EXTI_Line)
{
  /* Check the parameters */
  assert_param(IS_EXTI_LINE(EXTI_Line));
  
  EXTI->PR = EXTI_Line;
}

/**
  * @}
  */

/**
  * @}
  */

/**
  * @}
  */

/**
  * @}
  */

/******************* (C) COPYRIGHT 2010 STMicroelectronics *****END OF FILE****/
