/**
  @page RTC_Tamper RTC Tamper example
  
  @verbatim
  ******************** (C) COPYRIGHT 2012 STMicroelectronics *******************
  * @file    RTC/Tamper/readme.txt 
  * @author  MCD Application Team
  * @version V1.1.1
  * @date    13-April-2012
  * @brief   Description of the RTC Tamper 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 write/read data to/from RTC Backup data registers and 
demonstrates the Tamper detection feature.

One from the following clock can be used as RTC clock source (uncomment the
corresponding define in main.c):
  - LSE oscillator clock usually delivered by a 32.768 kHz quartz.
  - LSI oscillator clock

The associated firmware performs the following:
1. It configures the RTC_AF1 pin Tamper to be falling edge, and enables the Tamper 
   interrupt.
2. It writes the data to all RTC Backup data registers, then check whether the 
   data were correctly written. If yes, LED1 turns on, otherwise LED3 turns on.
3. On applying a low level on the RTC_AF1 pin (PC.13), the RTC backup data registers
   are reset and the Tamper interrupt is generated. The corresponding ISR then checks
   whether the RTC Backup data registers are cleared. If yes LED2 turns ON,
   otherwise LED4 turns ON.

 
@par Directory contents 

  - RTC/TimeStamp/stm32l1xx_conf.h    Library Configuration file
  - RTC/TimeStamp/stm32l1xx_it.c      Interrupt handlers
  - RTC/TimeStamp/stm32l1xx_it.h      Interrupt handlers header file
  - RTC/TimeStamp/main.c              Main program
  - RTC/TimeStamp/system_stm32l1xx.c  STM32L1xx system source file
  

@note The "system_stm32l1xx.c" is generated by an automatic clock configuration 
      system and can be easily customized to your own configuration. 
      To select different clock setup, use the "STM32L1xx_Clock_Configuration_V1.1.0.xls" 
      provided with the AN3309 package available on <a href="http://www.st.com/internet/mcu/family/141.jsp">  ST Microcontrollers </a>
         

@par Hardware and Software environment

  - This example runs on STM32L1xx Ultra Low Power High-, Medium-Density and Medium-Density Plus Devices.
  
  - This example has been tested with STMicroelectronics STM32L152D-EVAL (STM32L1xx 
    Ultra Low Power High-Density) and STM32L152-EVAL (STM32L1xx Ultra Low 
    Power Medium-Density) evaluation board and can be easily tailored to any 
    other supported device and development board.


  - STM32L152-EVAL Set-up
    - SEL button connected to PE.08 pin.
    - Connect PC.13 (EXTI Line13) to SEL buttons using a wire.
    - Use LD1, LD2 and LD4 leds connected respectively to PD.00, PD.01 and PD.05 pins.


  - STM32L152D-EVAL Set-up
    - SEL button connected to PG.13 pin.
    - Connect PC.13 (EXTI Line13) to SEL buttons using a wire.
    - Use LD1, LD2 and LD4 leds connected respectively to PD.03, PD.07 and PG.15 pins.


       
@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\STM32L1xx_StdPeriph_Templates
 - Open your preferred toolchain 
 - Rebuild all files and load your image into target memory
 - Run the example

@note
- Ultra Low Power Medium-density devices are STM32L151xx and STM32L152xx 
  microcontrollers where the Flash memory density ranges between 64 and 128 Kbytes.
- Ultra Low Power Medium-density Plus devices are STM32L151xx, STM32L152xx and 
  STM32L162xx microcontrollers where the Flash memory density is 256 Kbytes.
- Ultra Low Power High-density devices are STM32L151xx, STM32L152xx and STM32L162xx 
  microcontrollers where the Flash memory density is 384 Kbytes.
    
 * <h3><center>&copy; COPYRIGHT STMicroelectronics</center></h3>
 */

