/**
  @page RTC_ExitStandbyWithWakeUpTimer RTC example
  
  @verbatim
  ******************** (C) COPYRIGHT 2017 STMicroelectronics *******************
  * @file    Examples_LL/RTC/RTC_ExitStandbyWithWakeUpTimer/readme.txt 
  * @author  MCD Application Team
  * @brief   Description of the RTC example.
  ******************************************************************************
  *
  * Redistribution and use in source and binary forms, with or without modification,
  * are permitted provided that the following conditions are met:
  *   1. Redistributions of source code must retain the above copyright notice,
  *      this list of conditions and the following disclaimer.
  *   2. Redistributions in binary form must reproduce the above copyright notice,
  *      this list of conditions and the following disclaimer in the documentation
  *      and/or other materials provided with the distribution.
  *   3. Neither the name of STMicroelectronics nor the names of its contributors
  *      may be used to endorse or promote products derived from this software
  *      without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *
  ******************************************************************************
  @endverbatim

@par Example Description

This example shows how to configure the RTC in order to wake up from Standby mode
using RTC Wakeup Timer. Peripheral initialization is done using LL unitary services
functions for optimization purpose (performance and size).
  
In this example, after start-up, SYSCLK is configured to the max frequency using 
the PLL with HSI as clock source.

   @note LSI oscillator clock is used as RTC clock source by default.
      The user can use also LSE as RTC clock source. The user uncomment the adequate 
      line on the main.h file.
      The RTC wakup timer would be slowly higher than 5s since the MCU was in 
      standby mode and due to LSI or LSE stabilization time.

      @code
        #define RTC_CLOCK_SOURCE_LSI  
        /* #define RTC_CLOCK_SOURCE_LSE */
      @endcode
      LSI oscillator clock is delivered by a 32 kHz RC.
      LSE (when available on board) is delivered by a 32.768 kHz crystal.

Example execution:
   - 1st execution of the system, LED1 is quickly blinking (every 200ms).
   - RTC wakup timer is configured to 5 seconds
   - Press the user button:
     * System enters in standby mode (LED1 is switched off)
   - After 5 seconds, system resumes from standby mode, then LED1 is slowly blinking (every 500ms).

   - LED1 is toggling every 1 second: This indicates that the system generates an error.

@par Directory contents 

  - RTC/RTC_ExitStandbyWithWakeUpTimer/Inc/stm32f2xx_it.h          Interrupt handlers header file
  - RTC/RTC_ExitStandbyWithWakeUpTimer/Inc/main.h                  Header for main.c module
  - RTC/RTC_ExitStandbyWithWakeUpTimer/Inc/stm32_assert.h          Template file to include assert_failed function
  - RTC/RTC_ExitStandbyWithWakeUpTimer/Src/stm32f2xx_it.c          Interrupt handlers
  - RTC/RTC_ExitStandbyWithWakeUpTimer/Src/main.c                  Main program
  - RTC/RTC_ExitStandbyWithWakeUpTimer/Src/system_stm32f2xx.c      STM32F2xx system source file


@par Hardware and Software environment

  - This example runs on STM32F207xx devices.
    
  - This example has been tested with NUCLEO-F207ZG board and can be
    easily tailored to any other supported device and development board.


@par How to use it ? 

In order to make the program work, you must do the following :
 - Open your preferred toolchain
 - Rebuild all files and load your image into target memory
 - Run the example

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