(++) To wake up from the Standby mode with an RTC WakeUp event, it is necessary to:
             (+++) Enable the RTC WakeUp Interrupt using the RTC_ITConfig() function
             (+++) Configure the RTC to generate the RTC WakeUp event using the RTC_WakeUpClockConfig(), 
                   RTC_SetWakeUpCounter() and RTC_WakeUpCmd() functions.

    (+) Comparator auto-wakeup (AWU) from the Stop mode
        (++) To wake up from the Stop mode with an comparator 1 or comparator 2 wakeup
             event, it is necessary to:
             (+++) Configure the EXTI Line 21 for comparator 1 or EXTI Line 22 for comparator 2 
                   to be sensitive to to the selected edges (falling, rising or falling 
                   and rising) (Interrupt or Event modes) using the EXTI_Init() function.
             (+++) Configure the comparator to generate the event.

@endverbatim
  * @{
  */

/**
  * @brief  Enters/Exits the Low Power Run mode.
  * @note   Low power run mode can only be entered when VCORE is in range 2.
  *         In addition, the dynamic voltage scaling must not be used when Low 
  *         power run mode is selected. Only Stop and Sleep modes with regulator 
  *         configured in Low power mode is allowed when Low power run mode is 
  *         selected.  
  * @note   In Low power run mode, all I/O pins keep the same state as in Run mode.
  * @param  NewState: new state of the Low Power Run mode.
  *   This parameter can be: ENABLE or DISABLE.
  * @retval None
  */
void PWR_EnterLowPowerRunMode(FunctionalState NewState)
{
  /* Check the parameters */
  assert_param(IS_FUNCTIONAL_STATE(NewState));

  if (NewState != DISABLE)
  {
    PWR->CR |= PWR_CR_LPSDSR;
    PWR->CR |= PWR_CR_LPRUN;     
  }
  else
  {
    PWR->CR &= (uint32_t)~((uint32_t)PWR_CR_LPRUN); 
    PWR->CR &= (uint32_t)~((uint32_t)PWR_CR_LPSDSR);  
  }  
}

/**
  * @brief  Enters Sleep mode.
  * @note   In Sleep mode, all I/O pins keep the same state as in Run mode.  
  * @param  PWR_Regulator: specifies the regulator state in Sleep mode.
  *   This parameter can be one of the following values:
  *     @arg PWR_Regulator_ON: Sleep mode with regulator ON
  *     @arg PWR_Regulator_LowPower: Sleep mode with regulator in low power mode
  * @note   Low power sleep mode can only be entered when VCORE is in range 2.
  * @note   When the voltage regulator operates in low power mode, an additional 
  *         startup delay is incurred when waking up from Low power sleep mode.
  * @param  PWR_SLEEPEntry: specifies if SLEEP mode in entered with WFI or WFE instruction.
  *   This parameter can be one of the following values:
  *     @arg PWR_SLEEPEntry_WFI: enter SLEEP mode with WFI instruction
  *     @arg PWR_SLEEPEntry_WFE: enter SLEEP mode with WFE instruction
  * @retval None
  */
void PWR_EnterSleepMode(uint32_t PWR_Regulator, uint8_t PWR_SLEEPEntry)
{
  uint32_t tmpreg = 0;

  /* Check the parameters */
  assert_param(IS_PWR_REGULATOR(PWR_Regulator));

  assert_param(IS_PWR_SLEEP_ENTRY(PWR_SLEEPEntry));
  
  /* Select the regulator state in Sleep mode ---------------------------------*/
  tmpreg = PWR->CR;
  
  /* Clear PDDS and LPDSR bits */
  tmpreg &= CR_DS_MASK;
  
  /* Set LPDSR bit according to PWR_Regulator value */
  tmpreg |= PWR_Regulator;
  
  /* Store the new value */
  PWR->CR = tmpreg;

  /* Clear SLEEPDEEP bit of Cortex System Control Register */
  SCB->SCR &= (uint32_t)~((uint32_t)SCB_SCR_SLEEPDEEP);
  
  /* Select SLEEP mode entry -------------------------------------------------*/
  if(PWR_SLEEPEntry == PWR_SLEEPEntry_WFI)
  {   
    /* Request Wait For Interrupt */
    __WFI();
  }
  else
  {
    /* Request Wait For Event */
    __WFE();
  }
}

/**
  * @brief  Enters STOP mode.
  * @note   In Stop mode, all I/O pins keep the same state as in Run mode.
  * @note   When exiting Stop mode by issuing an interrupt or a wakeup event, 
  *         the MSI RC oscillator is selected as system clock.
  * @note   When the voltage regulator operates in low power mode, an additional 
  *         startup delay is incurred when waking up from Stop mode. 
  *         By keeping the internal regulator ON during Stop mode, the consumption 
  *         is higher although the startup time is reduced.
  * @param  PWR_Regulator: specifies the regulator state in STOP mode.
  *   This parameter can be one of the following values:
  *     @arg PWR_Regulator_ON: STOP mode with regulator ON.
  *     @arg PWR_Regulator_LowPower: STOP mode with regulator in low power mode.
  * @param  PWR_STOPEntry: specifies if STOP mode in entered with WFI or WFE instruction.
  *   This parameter can be one of the following values:
  *     @arg PWR_STOPEntry_WFI: enter STOP mode with WFI instruction.
  *     @arg PWR_STOPEntry_WFE: enter STOP mode with WFE instruction.
  * @retval None
  */
void PWR_EnterSTOPMode(uint32_t PWR_Regulator, uint8_t PWR_STOPEntry)
{
  uint32_t tmpreg = 0;
  
  /* Check the parameters */
  assert_param(IS_PWR_REGULATOR(PWR_Regulator));
  assert_param(IS_PWR_STOP_ENTRY(PWR_STOPEntry));
  
  /* Select the regulator state in STOP mode ---------------------------------*/
  tmpreg = PWR->CR;
  /* Clear PDDS and LPDSR bits */
  tmpreg &= CR_DS_MASK;
  
  /* Set LPDSR bit according to PWR_Regulator value */
  tmpreg |= PWR_Regulator;
  
  /* Store the new value */
  PWR->CR = tmpreg;
  
  /* Set SLEEPDEEP bit of Cortex System Control Register */
  SCB->SCR |= SCB_SCR_SLEEPDEEP;
  
  /* Select STOP mode entry --------------------------------------------------*/
  if(PWR_STOPEntry == PWR_STOPEntry_WFI)
  {   
    /* Request Wait For Interrupt */
    __WFI();
  }
  else
  {
    /* Request Wait For Event */
    __WFE();
  }
  /* Reset SLEEPDEEP bit of Cortex System Control Register */
  SCB->SCR &= (uint32_t)~((uint32_t)SCB_SCR_SLEEPDEEP);  
}

/**
  * @brief  Enters STANDBY mode.
  * @note   In Standby mode, all I/O pins are high impedance except for:
  *         Reset pad (still available) 
  *         RTC_AF1 pin (PC13) if configured for Wakeup pin 2 (WKUP2), tamper, 
  *         time-stamp, RTC Alarm out, or RTC clock calibration out.
  *         WKUP pin 1 (PA0) and WKUP pin 3 (PE6), if enabled.       
  * @param  None
  * @retval None
  */
void PWR_EnterSTANDBYMode(void)
{
  /* Clear Wakeup flag */
  PWR->CR |= PWR_CR_CWUF;
  
  /* Select STANDBY mode */
  PWR->CR |= PWR_CR_PDDS;
  
  /* Set SLEEPDEEP bit of Cortex System Control Register */
  SCB->SCR |= SCB_SCR_SLEEPDEEP;
  
/* This option is used to ensure that store operations are completed */
#if defined ( __CC_ARM   )
  __force_stores();
#endif
  /* Request Wait For Interrupt */
  __WFI();
}

/**
  * @}
  */

/** @defgroup PWR_Group7 Flags management functions
 *  @brief   Flags management functions 
 *
@verbatim   
  ==============================================================================
                       ##### Flags management functions #####
  ==============================================================================   

@endverbatim
  * @{
  */

/**
  * @brief  Checks whether the specified PWR flag is set or not.
  * @param  PWR_FLAG: specifies the flag to check.
  *   This parameter can be one of the following values:
  *     @arg PWR_FLAG_WU: Wake Up flag. This flag indicates that a wakeup event 
  *       was received from the WKUP pin or from the RTC alarm (Alarm A or Alarm B), 
  *       RTC Tamper event, RTC TimeStamp event or RTC Wakeup.
  *     @arg PWR_FLAG_SB: StandBy flag. This flag indicates that the system was
  *                       resumed from StandBy mode.    
  *     @arg PWR_FLAG_PVDO: PVD Output. This flag is valid only if PVD is enabled 
  *       by the PWR_PVDCmd() function.
  *     @arg PWR_FLAG_VREFINTRDY: Internal Voltage Reference Ready flag. This 
  *       flag indicates the state of the internal voltage reference, VREFINT.
  *     @arg PWR_FLAG_VOS: Voltage Scaling select flag. A delay is required for 
  *       the internal regulator to be ready after the voltage range is changed.
  *       The VOSF flag indicates that the regulator has reached the voltage level 
  *       defined with bits VOS[1:0] of PWR_CR register.
  *     @arg PWR_FLAG_REGLP: Regulator LP flag. This flag is set by hardware 
  *       when the MCU is in Low power run mode.
  *       When the MCU exits from Low power run mode, this flag stays SET until 
  *       the regulator is ready in main mode. A polling on this flag is 
  *       recommended to wait for the regulator main mode. 
  *       This flag is RESET by hardware when the regulator is ready.       
  * @retval The new state of PWR_FLAG (SET or RESET).
  */
FlagStatus PWR_GetFlagStatus(uint32_t PWR_FLAG)
{
  FlagStatus bitstatus = RESET;
  /* Check the parameters */
  assert_param(IS_PWR_GET_FLAG(PWR_FLAG));
  
  if ((PWR->CSR & PWR_FLAG) != (uint32_t)RESET)
  {
    bitstatus = SET;
  }
  else
  {
    bitstatus = RESET;
  }
  /* Return the flag status */
  return bitstatus;
}

/**
  * @brief  Clears the PWR's pending flags.
  * @param  PWR_FLAG: specifies the flag to clear.
  *   This parameter can be one of the following values:
  *     @arg PWR_FLAG_WU: Wake Up flag
  *     @arg PWR_FLAG_SB: StandBy flag
  * @retval None
  */
void PWR_ClearFlag(uint32_t PWR_FLAG)
{
  /* Check the parameters */
  assert_param(IS_PWR_CLEAR_FLAG(PWR_FLAG));
         
  PWR->CR |=  PWR_FLAG << 2;
}

/**
  * @}
  */

/**
  * @}
  */

/**
  * @}
  */

/**
  * @}
  */

/******************* (C) COPYRIGHT 2012 STMicroelectronics *****END OF FILE****/