/**
  @page EXTI_Example EXTI Configuration Example
  
  @verbatim
  ******************** (C) COPYRIGHT 2012 STMicroelectronics *******************
  * @file    EXTI/EXTI_Example/readme.txt 
  * @author  MCD Application Team
  * @version V1.0.0
  * @date    18-May-2012
  * @brief   Description of the EXTI example.
  ******************************************************************************
  *
  * Licensed under MCD-ST Liberty SW License Agreement V2, (the "License");
  * You may not use this file except in compliance with the License.
  * You may obtain a copy of the License at:
  *
  *        http://www.st.com/software_license_agreement_liberty_v2
  *
  * Unless required by applicable law or agreed to in writing, software 
  * distributed under the License is distributed on an "AS IS" BASIS, 
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  *
  ******************************************************************************
   @endverbatim

@par Example Description 

This example shows how to configure external interrupt lines.
In this example, 4 EXTI lines (EXTI0, EXTI8, EXTI9 and EXTI13) when using the STM320518-EVAL
are configured to generate an interrupt on each falling edge. In the interrupt routine a led
connected to a specific GPIO pin is toggled.

In this example
    - EXTI0  is mapped to PA0
    - EXTI8  is mapped to PC8 
    - EXTI9  is mapped to PC9  
    - EXTI13 is mapped to PC13

After EXTI configuration, a software interrupt is generated on the EXTI8 and LED1 toggles.
After that,
  when falling edge is detected on EXTI0, LED2 toggles
  when falling edge is detected on EXTI8, LED1 toggles
  when falling edge is detected on EXTI9, LED3 toggles
  when falling edge is detected on EXTI13, LED4 toggles

If STM320518-EVAL is used,
  when Joystick Sel push-button is pressed, LED2 toggles
  when Joystick Right push-button is pressed, LED1 toggles
  when Joystick Left push-button is pressed, LED3 toggles
  when Tamper push-button is pressed, LED4 toggles

In this example, EXTI0_Config() function can be substituted by 
STM_EVAL_PBInit(BUTTON_SEL, Mode_EXTI) provided in the STM320518-EVAL driver.


@par Directory contents 

  - EXTI/EXTI_Example/stm32f0xx_conf.h    Library Configuration file
  - EXTI/EXTI_Example/stm32f0xx_it.c      Interrupt handlers
  - EXTI/EXTI_Example/stm32f0xx_it.h      Interrupt handlers header file
  - EXTI/EXTI_Example/main.c              Main program
  - EXTI/EXTI_Example/system_stm32f0xx.c  STM32F0xx system source file
  
@note The "system_stm32f0xx.c" is generated by an automatic clock configuration 
      tool and can be easily customized to meet user application requirements. 
      To select different clock setup, use the "STM32F0xx_Clock_Configuration_VX.Y.Z.xls" 
      provided with the AN4055 package available on <a href="http://www.st.com/internet/mcu/class/1734.jsp">  ST Microcontrollers </a>
         

@par Hardware and Software environment

  - This example runs on STM32F0xx Devices.
  
  - This example has been tested with STMicroelectronics STM320518-EVAL (STM32F0xx)
    evaluation board and can be easily tailored to any other supported device 
    and development board.

  - STM320518-EVAL set-up
     - Use Joystick Right, Left and Sel push-button
     - USe Tamper push-button  


@par How to use it ? 

In order to make the program work, you must do the following :
 - Copy all source files from this example folder to the template folder under
   Project\STM32F0xx_StdPeriph_Templates
 - Open your preferred toolchain 
 - Rebuild all files and load your image into target memory
 - Run the example

 * <h3><center>&copy; COPYRIGHT STMicroelectronics</center></h3>
 */
