/**
  ******************************************************************************
  * @file    Examples_LL/RTC/RTC_ExitStandbyWithWakeUpTimer/Src/main.c
  * @author  MCD Application Team
  * @brief   This code example shows how to configure the RTC in order to work 
  *          with the WUT through the STM32F4xx RTC LL API.
  *          Peripheral initialization done using LL unitary services functions.
  ******************************************************************************
  * @attention
  *
  * <h2><center>&copy; COPYRIGHT(c) 2017 STMicroelectronics</center></h2>
  *
  * 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.
  *
  ******************************************************************************
  */

/* Includes ------------------------------------------------------------------*/
#include "main.h"

/** @addtogroup STM32F4xx_LL_Examples
  * @{
  */

/** @addtogroup RTC_ExitStandbyWithWakeUpTimer
  * @{
  */

/* Private typedef -----------------------------------------------------------*/
/* Private define ------------------------------------------------------------*/
/* Value defined for WUT */
#define RTC_WUT_TIME               ((uint32_t)5)     /* 5 s */

/* Oscillator time-out values */
#define LSI_TIMEOUT_VALUE          ((uint32_t)100)   /* 100 ms */
#define LSE_TIMEOUT_VALUE          ((uint32_t)5000)  /* 5 s */
#define RTC_TIMEOUT_VALUE          ((uint32_t)1000)  /* 1 s */

/* Defines related to Clock configuration */
/* Uncomment to enable the adequate Clock Source */
#define RTC_CLOCK_SOURCE_LSI
/*#define RTC_CLOCK_SOURCE_LSE*/

#ifdef RTC_CLOCK_SOURCE_LSI
/* ck_apre=LSIFreq/(ASYNC prediv + 1) = 256Hz with LSIFreq=32 kHz RC */
#define RTC_ASYNCH_PREDIV          ((uint32_t)0x7F)
/* ck_spre=ck_apre/(SYNC prediv + 1) = 1 Hz */
#define RTC_SYNCH_PREDIV           ((uint32_t)0x00F9)
#endif

#ifdef RTC_CLOCK_SOURCE_LSE
/* ck_apre=LSEFreq/(ASYNC prediv + 1) = 256Hz with LSEFreq=32768Hz */
#define RTC_ASYNCH_PREDIV          ((uint32_t)0x7F)
/* ck_spre=ck_apre/(SYNC prediv + 1) = 1 Hz */
#define RTC_SYNCH_PREDIV           ((uint32_t)0x00FF)
#endif

/* Private macro -------------------------------------------------------------*/
/* Private variables ---------------------------------------------------------*/
__IO uint8_t ubButtonPress = 0;

#if (USE_TIMEOUT == 1)
uint32_t Timeout = 0; /* Variable used for Timeout management */
#endif /* USE_TIMEOUT */

/* Private function prototypes -----------------------------------------------*/
void     SystemClock_Config(void);
void     Configure_RTC(void);
void     EnterStandbyMode(void);
void     LED_Init(void);
void     LED_Blinking(uint32_t Period);
void     UserButton_Init(void);
void     WaitForUserButtonPress(void);

/* Private functions ---------------------------------------------------------*/

/**
  * @brief  Main program
  * @param  None
  * @retval None
  */
int main(void)
{
  /* Configure the system clock to 100 MHz */
  SystemClock_Config();

  /* Initialize LED2 */
  LED_Init();

  /* Initialize button in EXTI mode */
  UserButton_Init();
  
  /* Configure RTC to use WUT */
  Configure_RTC();
  
  /* Check and handle if the system was resumed from StandBy mode */ 
  if(LL_PWR_IsActiveFlag_SB() != 1)
  {
    /* ##### Run after normal reset ##### */
    /* Fast Toggle LED in waiting for user-button press */
    WaitForUserButtonPress();
    
    /* Enable wake-up timer and enter in standby mode */
    EnterStandbyMode();
  }
  else
  {
    /* ##### Run after standby mode ##### */
    /* Clear Standby flag*/
    LL_PWR_ClearFlag_SB();
    
    /* Reset RTC Internal Wake up flag */
    LL_RTC_ClearFlag_WUT(RTC); 
    
    /* Slow Toggle LED */
    LED_Blinking(LED_BLINK_SLOW);
  }

  /* Infinite loop */
  while (1)
  {
  }
}

/**
  * Brief   This function configures RTC.
  * Param   None
  * Retval  None
  */
void Configure_RTC(void)
{
  /*##-1- Enables the PWR Clock and Enables access to the backup domain #######*/
  /* To change the source clock of the RTC feature (LSE, LSI), you have to:
     - Enable the power clock
     - Enable write access to configure the RTC clock source (to be done once after reset).
     - Reset the Back up Domain
     - Configure the needed RTC clock source */
  LL_APB1_GRP1_EnableClock(LL_APB1_GRP1_PERIPH_PWR);
  LL_PWR_EnableBkUpAccess();
  
  /*##-2- Configure LSE/LSI as RTC clock source ###############################*/
#ifdef RTC_CLOCK_SOURCE_LSE
  /* Enable LSE only if disabled.*/
  if (LL_RCC_LSE_IsReady() == 0)
  {
    LL_RCC_ForceBackupDomainReset();
    LL_RCC_ReleaseBackupDomainReset();
    LL_RCC_LSE_Enable();
#if (USE_TIMEOUT == 1)
    Timeout = LSE_TIMEOUT_VALUE;
#endif /* USE_TIMEOUT */
    while (LL_RCC_LSE_IsReady() != 1)
    {
#if (USE_TIMEOUT == 1)
      if (LL_SYSTICK_IsActiveCounterFlag()) 
      {
        Timeout --;
      }
      if (Timeout == 0)
      {
        /* LSE activation error */
        LED_Blinking(LED_BLINK_ERROR);
      }  
#endif /* USE_TIMEOUT */
    }
    LL_RCC_SetRTCClockSource(LL_RCC_RTC_CLKSOURCE_LSE);
    
    /*##-3- Enable RTC peripheral Clocks #######################################*/
    /* Enable RTC Clock */ 
    LL_RCC_EnableRTC();
  }
#elif defined(RTC_CLOCK_SOURCE_LSI)
  /* Enable LSI */
  LL_RCC_LSI_Enable();
#if (USE_TIMEOUT == 1)
  Timeout = LSI_TIMEOUT_VALUE;
#endif /* USE_TIMEOUT */
  while (LL_RCC_LSI_IsReady() != 1)
  {
#if (USE_TIMEOUT == 1)
    if (LL_SYSTICK_IsActiveCounterFlag()) 
    {
      Timeout --;
    }
    if (Timeout == 0)
    {
      /* LSI activation error */
      LED_Blinking(LED_BLINK_ERROR);
    }  
#endif /* USE_TIMEOUT */
  }
  LL_RCC_ForceBackupDomainReset();
  LL_RCC_ReleaseBackupDomainReset();
  LL_RCC_SetRTCClockSource(LL_RCC_RTC_CLKSOURCE_LSI);
  
  /*##-3- Enable RTC peripheral Clocks #######################################*/
  /* Enable RTC Clock */ 
  LL_RCC_EnableRTC();

#else
#error "configure clock for RTC"
#endif

  /*##-4- Configure RTC ######################################################*/
  /* Disable RTC registers write protection */
  LL_RTC_DisableWriteProtection(RTC);
  
  /* Set prescaler according to source clock */
  LL_RTC_SetAsynchPrescaler(RTC, RTC_ASYNCH_PREDIV);
  LL_RTC_SetSynchPrescaler(RTC, RTC_SYNCH_PREDIV);

  /* Disable wake up timer to modify it */
  LL_RTC_WAKEUP_Disable(RTC);
  
  /* Wait until it is allow to modify wake up reload value */
#if (USE_TIMEOUT == 1)
  Timeout = RTC_TIMEOUT_VALUE;
#endif /* USE_TIMEOUT */

  while (LL_RTC_IsActiveFlag_WUTW(RTC) != 1)
  {
#if (USE_TIMEOUT == 1)
    if (LL_SYSTICK_IsActiveCounterFlag())
    {
      Timeout --;
    }
    if (Timeout == 0)
    {
      /* LSI activation error */
      LED_Blinking(LED_BLINK_ERROR);
    }  
#endif /* USE_TIMEOUT */
  }
  
  /* Setting the Wakeup time to RTC_WUT_TIME s
       If LL_RTC_WAKEUPCLOCK_CKSPRE is selected, the frequency is 1Hz, 
       this allows to get a wakeup time equal to RTC_WUT_TIME s 
       if the counter is RTC_WUT_TIME */
  LL_RTC_WAKEUP_SetAutoReload(RTC, RTC_WUT_TIME);
  LL_RTC_WAKEUP_SetClock(RTC, LL_RTC_WAKEUPCLOCK_CKSPRE);
  
  /* Enable RTC registers write protection */
  LL_RTC_EnableWriteProtection(RTC);
  
}

/**
  * @brief  Function to configure and enter in STANDBY Mode.
  * @param  None
  * @retval None
  */
void EnterStandbyMode(void)
{
  /* ######## ENABLE WUT #################################################*/
  /* Disable RTC registers write protection */
  LL_RTC_DisableWriteProtection(RTC);
 
  /* Enable wake up counter and wake up interrupt */
  /* Note: Periodic wakeup interrupt should be enabled to exit the device 
     from low-power modes.*/
  LL_RTC_EnableIT_WUT(RTC);
  LL_RTC_WAKEUP_Enable(RTC);
  
  /* Enable RTC registers write protection */
  LL_RTC_EnableWriteProtection(RTC);
  
  /* ######## ENTER IN STANDBY MODE ######################################*/
  /** Request to enter STANDBY mode
    * Following procedure describe in STM32F4xx Reference Manual
    * See PWR part, section Low-power modes, Standby mode
    */
  /* Reset Internal Wake up flag */
  LL_RTC_ClearFlag_WUT(RTC); 
  
  /* Set Stand-by mode */
  LL_PWR_SetPowerMode(LL_PWR_MODE_STANDBY);
  
  /* Set SLEEPDEEP bit of Cortex System Control Register */
  LL_LPM_EnableDeepSleep();
  
  /* This option is used to ensure that store operations are completed */
#if defined ( __CC_ARM)
  __force_stores();
#endif

  /* Request Wait For Interrupt */
  __WFI();
}

/**
  * @brief  Initialize LED2.
  * @param  None
  * @retval None
  */
void LED_Init(void)
{
  /* Enable the LED2 Clock */
  LED2_GPIO_CLK_ENABLE();

  /* Configure IO in output push-pull mode to drive external LED2 */
  LL_GPIO_SetPinMode(LED2_GPIO_PORT, LED2_PIN, LL_GPIO_MODE_OUTPUT);
  /* Reset value is LL_GPIO_OUTPUT_PUSHPULL */
  //LL_GPIO_SetPinOutputType(LED2_GPIO_PORT, LED2_PIN, LL_GPIO_OUTPUT_PUSHPULL);
  /* Reset value is LL_GPIO_SPEED_FREQ_LOW */
  //LL_GPIO_SetPinSpeed(LED2_GPIO_PORT, LED2_PIN, LL_GPIO_SPEED_FREQ_LOW);
  /* Reset value is LL_GPIO_PULL_NO */
  //LL_GPIO_SetPinPull(LED2_GPIO_PORT, LED2_PIN, LL_GPIO_PULL_NO);
}

/**
  * @brief  Set LED2 to Blinking mode for an infinite loop (toggle period based on value provided as input parameter).
  * @param  Period : Period of time (in ms) between each toggling of LED
  *   This parameter can be user defined values. Pre-defined values used in that example are :
  *     @arg LED_BLINK_FAST : Fast Blinking
  *     @arg LED_BLINK_SLOW : Slow Blinking
  *     @arg LED_BLINK_ERROR : Error specific Blinking
  * @retval None
  */
void LED_Blinking(uint32_t Period)
{
  /* Toggle IO in an infinite loop */
  while (1)
  {
    LL_GPIO_TogglePin(LED2_GPIO_PORT, LED2_PIN);  
    LL_mDelay(Period);
  }
}

/**
  * @brief  Configures User push-button in EXTI mode.
  * @param  None  
  * @retval None
  */
void UserButton_Init(void)
{
  /* Enable the BUTTON Clock */
  USER_BUTTON_GPIO_CLK_ENABLE();
  
  /* Configure GPIO for BUTTON */
  LL_GPIO_SetPinMode(USER_BUTTON_GPIO_PORT, USER_BUTTON_PIN, LL_GPIO_MODE_INPUT);
  LL_GPIO_SetPinPull(USER_BUTTON_GPIO_PORT, USER_BUTTON_PIN, LL_GPIO_PULL_NO);
  /* Connect External Line to the GPIO*/
  USER_BUTTON_SYSCFG_SET_EXTI();
  
  /* Enable a rising trigger EXTI line 13 Interrupt */
  USER_BUTTON_EXTI_LINE_ENABLE();
  USER_BUTTON_EXTI_FALLING_TRIG_ENABLE();
  
  /* Configure NVIC for USER_BUTTON_EXTI_IRQn */
  NVIC_EnableIRQ(USER_BUTTON_EXTI_IRQn); 
  NVIC_SetPriority(USER_BUTTON_EXTI_IRQn,0x03);  
}

/**
  * @brief  Wait for User push-button press to start transfer.
  * @param  None 
  * @retval None
  */
  /*  */
void WaitForUserButtonPress(void)
{
  while (ubButtonPress == 0)
  {
    LL_GPIO_TogglePin(LED2_GPIO_PORT, LED2_PIN);
    LL_mDelay(LED_BLINK_FAST);
  }
}

/**
  * @brief  System Clock Configuration
  *         The system Clock is configured as follow :
  *            System Clock source            = PLL (HSE)
  *            SYSCLK(Hz)                     = 100000000
  *            HCLK(Hz)                       = 100000000
  *            AHB Prescaler                  = 1
  *            APB1 Prescaler                 = 2
  *            APB2 Prescaler                 = 1
  *            HSE Frequency(Hz)              = 8000000
  *            PLL_M                          = 8
  *            PLL_N                          = 400
  *            PLL_P                          = 4
  *            VDD(V)                         = 3.3
  *            Main regulator output voltage  = Scale1 mode
  *            Flash Latency(WS)              = 3
  * @param  None
  * @retval None
  */
void SystemClock_Config(void)
{
  /* Enable HSE oscillator */
  LL_RCC_HSE_EnableBypass();
  LL_RCC_HSE_Enable();
  while(LL_RCC_HSE_IsReady() != 1)
  {
  };

  /* Set FLASH latency */
  LL_FLASH_SetLatency(LL_FLASH_LATENCY_3);

  /* Main PLL configuration and activation */
  LL_RCC_PLL_ConfigDomain_SYS(LL_RCC_PLLSOURCE_HSE, LL_RCC_PLLM_DIV_8, 400, LL_RCC_PLLP_DIV_4);
  LL_RCC_PLL_Enable();
  while(LL_RCC_PLL_IsReady() != 1)
  {
  };

  /* Sysclk activation on the main PLL */
  LL_RCC_SetAHBPrescaler(LL_RCC_SYSCLK_DIV_1);
  LL_RCC_SetSysClkSource(LL_RCC_SYS_CLKSOURCE_PLL);
  while(LL_RCC_GetSysClkSource() != LL_RCC_SYS_CLKSOURCE_STATUS_PLL)
  {
  };

  /* Set APB1 & APB2 prescaler */
  LL_RCC_SetAPB1Prescaler(LL_RCC_APB1_DIV_2);
  LL_RCC_SetAPB2Prescaler(LL_RCC_APB2_DIV_1);

  /* Set systick to 1ms */
  SysTick_Config(100000000 / 1000);

  /* Update CMSIS variable (which can be updated also through SystemCoreClockUpdate function) */
  SystemCoreClock = 100000000;
}

/******************************************************************************/
/*   USER IRQ HANDLER TREATMENT                                               */
/******************************************************************************/
/**
  * @brief  Function to manage User button
  * @param  None
  * @retval None
  */
void UserButton_Callback(void)
{
  /* Update User push-button variable : to be checked in waiting loop in main function */
  ubButtonPress = 1;
}

#ifdef  USE_FULL_ASSERT

/**
  * @brief  Reports the name of the source file and the source line number
  *         where the assert_param error has occurred.
  * @param  file: pointer to the source file name
  * @param  line: assert_param error line source number
  * @retval None
  */
void assert_failed(uint8_t *file, uint32_t line)
{
  /* User can add his own implementation to report the file name and line number,
     ex: printf("Wrong parameters value: file %s on line %d", file, line) */

  /* Infinite loop */
  while (1)
  {
  }
}
#endif

/**
  * @}
  */

/**
  * @}
  */

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