/**
  @page PWR_LPRUN Low Power run Mode Example
  
  @verbatim
  ******************** (C) COPYRIGHT 2014 STMicroelectronics *******************
  * @file    PWR/PWR_LPRUN/readme.txt 
  * @author  MCD Application Team
  * @version $VERSION$
  * @date    $DATE$
  * @brief   This example shows how to use STM32L1xx PWR HAL API to enter the
  *          system to Low Power Run mode and exit from this mode using Key 
  *          push button.
  ******************************************************************************
  *
  * 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 enters the system to Low Power Run mode and exit 
from this mode using Key push button.
This example shows also how to configure the STM32L1xx system to measure 
LP Run mode current consumption.

In the associated software, the system clock is set to 32 KHz.

 @note This mode is achieved with the multispeed internal (MSI) RC oscillator set 
       to the lowspeed clock (max 131 kHz), execution from SRAM or Flash memory, 
       and internal regulator in low-power mode to minimize the regulator's 
       operating current.

In the associated software
  - the system clock is set to 32 KHz
  - the External line 15 to 10 (PC.13) is used to enter and exit the Low Power Run mode.

The system enters LP RUN mode by pressing User push-button (PC.13) and will wait 
for the same button to be pressed to exit LP RUN mode. Current consumption could 
be monitored through an amperemeter.

This behavior is repeated in an infinite loop.
 - LED2 ON: HAL configuration failed (system will go to an infinite loop)

    - Low Power Run Mode from FLASH
    ================================
          - Regulator in LP mode
          - System Running at MSI (~32KHz)
          - Flash 0 wait state  
          - MSI Range 0
          - Voltage Range 2
          - Code running from Internal FLASH
          - All peripherals OFF
          - Wakeup using Key Button PC.13

@note This example can not be used in DEBUG mode, this is 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 need to ensure that the SysTick time base is always set to 1 millisecond
      to have correct HAL operation.
      
@par Directory contents 

  - PWR/PWR_LPRUN/Inc/stm32l1xx_conf.h         HAL Configuration file
  - PWR/PWR_LPRUN/Inc/stm32l1xx_it.h           Header for stm32l1xx_it.c
  - PWR/PWR_LPRUN/Inc/main.h                   Header file for main.c
  - PWR/PWR_LPRUN/Src/system_stm32l1xx.c       STM32L1xx system clock configuration file
  - PWR/PWR_LPRUN/Src/stm32l1xx_it.c           Interrupt handlers
  - PWR/PWR_LPRUN/Src/main.c                   Main program

@par Hardware and Software environment

  - This example runs on STM32L152xE devices
    
      
  - This example has been tested with STMicroelectronics STM32L152RE-Nucleo Rev C
    evaluation board and can be easily tailored to any other supported device 
    and development board.

  - STM32L152RE-Nucleo Rev C Set-up
    - Use the User push-button connected to pin PC.13 (External line 15 to 10)
    - Connect an amperemeter to JP6 to measure the IDD current

@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>
 */
