/**
  @page PWR_STOP PWR Example
  
  @verbatim
  ******************** (C) COPYRIGHT 2017 STMicroelectronics *******************
  * @file    Examples_MIX/PWR/PWR_STOP/readme.txt 
  * @author  MCD Application Team
  * @brief   Description of the PWR_STOP 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 enter the system in STOP with Low power regulator mode and wake-up from this
mode using external RESET or wake-up interrupt (all the RCC functions calls use 
RCC LL API for footprint and performance improvements).

In the associated software, the system clock is set to 120 MHz, an EXTI line
is connected to the user button through PC.13 and configured to generate an 
interrupt on falling edge upon key press.
The SysTick is programmed to generate an interrupt each 1 ms and in the SysTick 
interrupt handler, LED1 is toggled in order to indicate whether the MCU is in STOP with Low power regulator mode 
or RUN mode.

5 seconds after start-up, the system automatically enters STOP with Low power regulator mode and 
LED1 stops toggling.

The Key push-button can be pressed at any time to wake-up the system. 
The software then comes back in RUN mode for 5 sec. before automatically entering STOP with Low power regulator mode again. 

Two leds LED1 and LED2 are used to monitor the system state as following:
 - LED2 ON: configuration failed (system will go to an infinite loop)
 - LED1 toggling: system in RUN mode
 - LED1 off : system in STOP with Low power regulator mode

These steps are repeated in an infinite loop.

@note To measure the current consumption in STOP with Low power regulator mode, remove JP5 jumper 
      and connect an amperemeter to JP5 to measure IDD current.     

@note This example can not be used in DEBUG mode due to the fact 
      that the Cortex-M3 core is no longer clocked during low power mode 
      so debugging features are disabled.

@note Care must be taken when using HAL_Delay(), this function provides accurate delay (in milliseconds)
      based on variable incremented in SysTick ISR. This implies that if HAL_Delay() is called from
      a peripheral ISR process, then the SysTick interrupt must have higher priority (numerically lower)
      than the peripheral interrupt. Otherwise the caller ISR process will be blocked.
      To change the SysTick interrupt priority you have to use HAL_NVIC_SetPriority() function.
      
@note The application needs to ensure that the SysTick time base is always set to 1 millisecond
      to have correct HAL operation.
      

@par Directory contents 

  - Examples_MIX/PWR/PWR_STOP/Inc/stm32f2xx_conf.h         HAL Configuration file
  - Examples_MIX/PWR/PWR_STOP/Inc/stm32f2xx_it.h           Header for stm32f2xx_it.c
  - Examples_MIX/PWR/PWR_STOP/Inc/main.h                   Header file for main.c
  - Examples_MIX/PWR/PWR_STOP/Src/system_stm32f2xx.c       STM32F2xx system clock configuration file
  - Examples_MIX/PWR/PWR_STOP/Src/stm32f2xx_it.c           Interrupt handlers
  - Examples_MIX/PWR/PWR_STOP/Src/main.c                   Main program
  - Examples_MIX/PWR/PWR_STOP/Src/stm32f2xx_hal_msp.c      HAL MSP module

@par Hardware and Software environment

  - This example runs on STM32F2xx devices
    

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

  - NUCLEO-F207ZG set-up:
    - Use LED1 and LED2 connected respectively to PB.0 and PB.07 pins
    - Key push-button connected to pin PC.13 (EXTI Line13)
    
@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>
 */
