/**
  ******************************************************************************
  * @file    stm32f0xx_hal_timebase_rtc_wakeup.c 
  * @brief   HAL time base based on the hardware RTC_WAKEUP.
  *    
  *          This file overrides the native HAL time base functions (defined as weak)
  *          to use the RTC WAKEUP for the time base generation:
  *           + Intializes the RTC peripheral and configures the wakeup timer to be
  *             incremented each 1ms
  *           + The wakeup feature is configured to assert an interrupt each 1ms 
  *           + HAL_IncTick is called inside the HAL_RTCEx_WakeUpTimerEventCallback
  *           + HSE (default), LSE or LSI can be selected as RTC clock source
 @verbatim
  ==============================================================================
                        ##### How to use this driver #####
  ==============================================================================
    [..]
    This file must be copied to the application folder and modified as follows:
    (#) Rename it to 'stm32f0xx_hal_timebase_rtc_wakeup.c'
    (#) Add this file and the RTC HAL drivers to your project and uncomment
       HAL_RTC_MODULE_ENABLED define in stm32f0xx_hal_conf.h 

    [..]
    (@) HAL RTC alarm and HAL RTC wakeup drivers can’t be used with low power modes:
        The wake up capability of the RTC may be intrusive in case of prior low power mode
        configuration requiring different wake up sources.
        Application/Example behavior is no more guaranteed 
    (@) The stm32f0xx_hal_timebase_tim use is recommended for the Applications/Examples
          requiring low power modes

  @endverbatim
  ******************************************************************************
  * @attention
  *
  * <h2><center>&copy; Copyright (c) 2016 STMicroelectronics.
  * All rights reserved.</center></h2>
  *
  * This software component is licensed by ST under BSD 3-Clause license,
  * the "License"; You may not use this file except in compliance with the
  * License. You may obtain a copy of the License at:
  *                        opensource.org/licenses/BSD-3-Clause
  *
  ******************************************************************************
  */

/* Includes ------------------------------------------------------------------*/
#include "stm32f0xx_hal.h"
/** @addtogroup STM32F0xx_HAL_Driver
  * @{
  */

/** @defgroup HAL_TimeBase_RTC_WakeUp  HAL TimeBase RTC WakeUp 
  * @{
  */ 

/* Private typedef -----------------------------------------------------------*/
/* Private define ------------------------------------------------------------*/

/* Uncomment the line below to select the appropriate RTC Clock source for your application: 
  + RTC_CLOCK_SOURCE_HSE: can be selected for applications requiring timing precision.
  + RTC_CLOCK_SOURCE_LSE: can be selected for applications with low constraint on timing
                          precision.
  + RTC_CLOCK_SOURCE_LSI: can be selected for applications with low constraint on timing
                          precision.
  */
#define RTC_CLOCK_SOURCE_HSE 
/* #define RTC_CLOCK_SOURCE_LSE */
/* #define RTC_CLOCK_SOURCE_LSI */

#if defined(RTC_CLOCK_SOURCE_HSE)
  #define RTC_ASYNCH_PREDIV       49U
  #define RTC_SYNCH_PREDIV        4U
#elif defined(RTC_CLOCK_SOURCE_LSE)
  #define RTC_ASYNCH_PREDIV       0U
  #define RTC_SYNCH_PREDIV        31U
#else        /* CLOCK_SOURCE_LSI */
  #define RTC_ASYNCH_PREDIV       0U
  #define RTC_SYNCH_PREDIV        39U
#endif       /* RTC_CLOCK_SOURCE_HSE */

/* Private macro -------------------------------------------------------------*/
/* Private variables ---------------------------------------------------------*/
RTC_HandleTypeDef        hRTC_Handle;

/* Private function prototypes -----------------------------------------------*/
void RTC_IRQHandler(void);

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

/**
  * @brief  This function configures the RTC_WKUP as a time base source. 
  *         The time source is configured  to have 1ms time base with a dedicated 
  *         Tick interrupt priority. 
  *         Wakeup Time base = ((RTC_ASYNCH_PREDIV + 1) * (RTC_SYNCH_PREDIV + 1)) / RTC_CLOCK 
                             = 1ms
  *         Wakeup Time = WakeupTimebase * WakeUpCounter (0 + 1) 
                        = 1 ms
  * @note   This function is called  automatically at the beginning of program after
  *         reset by HAL_Init() or at any time when clock is configured, by HAL_RCC_ClockConfig(). 
  * @param  TickPriority: Tick interrupt priority.
  * @retval HAL status
  */
HAL_StatusTypeDef HAL_InitTick (uint32_t TickPriority)
{
  __IO uint32_t counter = 0U;

  RCC_OscInitTypeDef        RCC_OscInitStruct;
  RCC_PeriphCLKInitTypeDef  PeriphClkInitStruct;

#ifdef RTC_CLOCK_SOURCE_LSE
  /* Configue LSE as RTC clock soucre */
  RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_LSE;
  RCC_OscInitStruct.PLL.PLLState = RCC_PLL_NONE;
  RCC_OscInitStruct.LSEState = RCC_LSE_ON;
  PeriphClkInitStruct.RTCClockSelection = RCC_RTCCLKSOURCE_LSE;
#elif defined (RTC_CLOCK_SOURCE_LSI)
  /* Configue LSI as RTC clock soucre */
  RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_LSI;
  RCC_OscInitStruct.PLL.PLLState = RCC_PLL_NONE;
  RCC_OscInitStruct.LSIState = RCC_LSI_ON;
  PeriphClkInitStruct.RTCClockSelection = RCC_RTCCLKSOURCE_LSI;
#elif defined (RTC_CLOCK_SOURCE_HSE)
  /* Configue HSE as RTC clock soucre */
  RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE;
  RCC_OscInitStruct.PLL.PLLState = RCC_PLL_NONE;
  RCC_OscInitStruct.HSEState = RCC_HSE_ON;
  PeriphClkInitStruct.RTCClockSelection = RCC_RTCCLKSOURCE_HSE_DIV32;
#else
#error Please select the RTC Clock source
#endif /* RTC_CLOCK_SOURCE_LSE */

  if(HAL_RCC_OscConfig(&RCC_OscInitStruct) == HAL_OK)
  { 
    PeriphClkInitStruct.PeriphClockSelection = RCC_PERIPHCLK_RTC;
    if(HAL_RCCEx_PeriphCLKConfig(&PeriphClkInitStruct) == HAL_OK)
    {
      /* Enable RTC Clock */
      __HAL_RCC_RTC_ENABLE();
      /* The time base should be 1ms 
         Time base = ((RTC_ASYNCH_PREDIV + 1) * (RTC_SYNCH_PREDIV + 1)) / RTC_CLOCK 
         HSE/32 as RTC clock and HSE 8MHz
           Time base = ((49 + 1) * (4 + 1)) / 250kHz
                     = 1ms
         LSE as RTC clock 
           Time base = ((31 + 1) * (0 + 1)) / 32.768Khz
                     = ~1ms
         LSI as RTC clock 
           Time base = ((39 + 1) * (0 + 1)) / 40Khz
                     = 1ms
      */
      hRTC_Handle.Instance = RTC;
      hRTC_Handle.Init.HourFormat = RTC_HOURFORMAT_24;
      hRTC_Handle.Init.AsynchPrediv = RTC_ASYNCH_PREDIV;
      hRTC_Handle.Init.SynchPrediv = RTC_SYNCH_PREDIV;
      hRTC_Handle.Init.OutPut = RTC_OUTPUT_DISABLE;
      hRTC_Handle.Init.OutPutPolarity = RTC_OUTPUT_POLARITY_HIGH;
      hRTC_Handle.Init.OutPutType = RTC_OUTPUT_TYPE_OPENDRAIN;
      HAL_RTC_Init(&hRTC_Handle);

      /* Disable the write protection for RTC registers */
      __HAL_RTC_WRITEPROTECTION_DISABLE(&hRTC_Handle);

      /* Disable the Wake-up Timer */
      __HAL_RTC_WAKEUPTIMER_DISABLE(&hRTC_Handle);

      /* In case of interrupt mode is used, the interrupt source must disabled */ 
      __HAL_RTC_WAKEUPTIMER_DISABLE_IT(&hRTC_Handle,RTC_IT_WUT);

      /* Wait till RTC WUTWF flag is set  */
      while(__HAL_RTC_WAKEUPTIMER_GET_FLAG(&hRTC_Handle, RTC_FLAG_WUTWF) == RESET)
      {
        if(counter++ == (SystemCoreClock /48U)) 
        {
          return HAL_ERROR;
        }
      }

      /* Clear PWR wake up Flag */
      __HAL_PWR_CLEAR_FLAG(PWR_FLAG_WU);

      /* Clear RTC Wake Up timer Flag */
      __HAL_RTC_WAKEUPTIMER_CLEAR_FLAG(&hRTC_Handle, RTC_FLAG_WUTF);

      /* Configure the Wake-up Timer counter */
      hRTC_Handle.Instance->WUTR = 0U;

      /* Clear the Wake-up Timer clock source bits in CR register */
      hRTC_Handle.Instance->CR &= (uint32_t)~RTC_CR_WUCKSEL;

      /* Configure the clock source */
      hRTC_Handle.Instance->CR |= (uint32_t)RTC_WAKEUPCLOCK_CK_SPRE_16BITS;

      /* RTC WakeUpTimer Interrupt Configuration: EXTI configuration */
      __HAL_RTC_WAKEUPTIMER_EXTI_ENABLE_IT();

      __HAL_RTC_WAKEUPTIMER_EXTI_ENABLE_RISING_EDGE();

      /* Configure the Interrupt in the RTC_CR register */
      __HAL_RTC_WAKEUPTIMER_ENABLE_IT(&hRTC_Handle,RTC_IT_WUT);

      /* Enable the Wake-up Timer */
      __HAL_RTC_WAKEUPTIMER_ENABLE(&hRTC_Handle);

      /* Enable the write protection for RTC registers */
      __HAL_RTC_WRITEPROTECTION_ENABLE(&hRTC_Handle);

      HAL_NVIC_SetPriority(RTC_IRQn, TickPriority, 0U);
      HAL_NVIC_EnableIRQ(RTC_IRQn); 
      return HAL_OK;
    }
  }
  return HAL_ERROR;
}

/**
  * @brief  Suspend Tick increment.
  * @note   Disable the tick increment by disabling RTC_WKUP interrupt.
  * @param  None
  * @retval None
  */
void HAL_SuspendTick(void)
{
  /* Disable the write protection for RTC registers */
  __HAL_RTC_WRITEPROTECTION_DISABLE(&hRTC_Handle);
  /* Disable WAKE UP TIMER Interrupt */
  __HAL_RTC_WAKEUPTIMER_DISABLE_IT(&hRTC_Handle, RTC_IT_WUT);
  /* Enable the write protection for RTC registers */
  __HAL_RTC_WRITEPROTECTION_ENABLE(&hRTC_Handle);
}

/**
  * @brief  Resume Tick increment.
  * @note   Enable the tick increment by Enabling RTC_WKUP interrupt.
  * @param  None
  * @retval None
  */
void HAL_ResumeTick(void)
{
  /* Disable the write protection for RTC registers */
  __HAL_RTC_WRITEPROTECTION_DISABLE(&hRTC_Handle);
  /* Enable  WAKE UP TIMER  interrupt */
  __HAL_RTC_WAKEUPTIMER_ENABLE_IT(&hRTC_Handle, RTC_IT_WUT);
  /* Enable the write protection for RTC registers */
  __HAL_RTC_WRITEPROTECTION_ENABLE(&hRTC_Handle);
}

/**
  * @brief  Wake Up Timer Event Callback in non blocking mode
  * @note   This function is called  when RTC_WKUP interrupt took place, inside
  * RTC_IRQHandler(). It makes a direct call to HAL_IncTick() to increment
  * a global variable "uwTick" used as application time base.
  * @param  hrtc : RTC handle
  * @retval None
  */
void HAL_RTCEx_WakeUpTimerEventCallback(RTC_HandleTypeDef *hrtc)
{
  HAL_IncTick();
}

/**
  * @brief  This function handles  WAKE UP TIMER  interrupt request.
  * @param  None
  * @retval None
  */
void RTC_IRQHandler(void)
{
  HAL_RTCEx_WakeUpTimerIRQHandler(&hRTC_Handle);
}

/**
  * @}
  */

/**
  * @}
  */

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