drivers/src/stm32l0xx_ll_utils.c

/**
  ******************************************************************************
  * @file    stm32l0xx_ll_utils.c
  * @author  MCD Application Team
  * @brief   UTILS LL module driver.
  ******************************************************************************
  * @attention
  *
  * Copyright (c) 2016 STMicroelectronics.
  * All rights reserved.
  *
  * This software is licensed under terms that can be found in the LICENSE file
  * in the root directory of this software component.
  * If no LICENSE file comes with this software, it is provided AS-IS.
  *
  ******************************************************************************
  */
/* Includes ------------------------------------------------------------------*/
#include "stm32l0xx_ll_rcc.h"
#include "stm32l0xx_ll_utils.h"
#include "stm32l0xx_ll_system.h"
#include "stm32l0xx_ll_pwr.h"
#ifdef  USE_FULL_ASSERT
#include "stm32_assert.h"
#else
#define assert_param(expr) ((void)0U)
#endif

/** @addtogroup STM32L0xx_LL_Driver
  * @{
  */

/** @addtogroup UTILS_LL
  * @{
  */

/* Private types -------------------------------------------------------------*/
/* Private variables ---------------------------------------------------------*/
/* Private constants ---------------------------------------------------------*/
/** @addtogroup UTILS_LL_Private_Constants
  * @{
  */
#define UTILS_MAX_FREQUENCY_SCALE1  (32000000U)        /*!< Maximum frequency for system clock at power scale1, in Hz */
#define UTILS_MAX_FREQUENCY_SCALE2  (16000000U)        /*!< Maximum frequency for system clock at power scale2, in Hz */
#define UTILS_MAX_FREQUENCY_SCALE3  (4194304U)         /*!< Maximum frequency for system clock at power scale3, in Hz */

/* Defines used for PLL range */
#define UTILS_PLLVCO_OUTPUT_SCALE1  (96000000U)        /*!< Frequency max for PLLVCO output at power scale1, in Hz  */
#define UTILS_PLLVCO_OUTPUT_SCALE2  (48000000U)        /*!< Frequency max for PLLVCO output at power scale2, in Hz  */
#define UTILS_PLLVCO_OUTPUT_SCALE3  (24000000U)        /*!< Frequency max for PLLVCO output at power scale3, in Hz  */

/* Defines used for HSE range */
#define UTILS_HSE_FREQUENCY_MIN     (1000000U)         /*!< Frequency min for HSE frequency, in Hz   */
#define UTILS_HSE_FREQUENCY_MAX     (24000000U)        /*!< Frequency max for HSE frequency, in Hz   */

/* Defines used for FLASH latency according to HCLK Frequency */
#define UTILS_SCALE1_LATENCY1_FREQ  (16000000U)        /*!< HCLK frequency to set FLASH latency 1 in power scale 1 */
#define UTILS_SCALE2_LATENCY1_FREQ  (8000000U)         /*!< HCLK frequency to set FLASH latency 1 in power scale 2 */
#define UTILS_SCALE3_LATENCY1_FREQ  (2000000U)         /*!< HCLK frequency to set FLASH latency 1 in power scale 3 */
/**
  * @}
  */
/* Private macros ------------------------------------------------------------*/
/** @addtogroup UTILS_LL_Private_Macros
  * @{
  */
#define IS_LL_UTILS_SYSCLK_DIV(__VALUE__) (((__VALUE__) == LL_RCC_SYSCLK_DIV_1)   \
                                        || ((__VALUE__) == LL_RCC_SYSCLK_DIV_2)   \
                                        || ((__VALUE__) == LL_RCC_SYSCLK_DIV_4)   \
                                        || ((__VALUE__) == LL_RCC_SYSCLK_DIV_8)   \
                                        || ((__VALUE__) == LL_RCC_SYSCLK_DIV_16)  \
                                        || ((__VALUE__) == LL_RCC_SYSCLK_DIV_64)  \
                                        || ((__VALUE__) == LL_RCC_SYSCLK_DIV_128) \
                                        || ((__VALUE__) == LL_RCC_SYSCLK_DIV_256) \
                                        || ((__VALUE__) == LL_RCC_SYSCLK_DIV_512))

#define IS_LL_UTILS_APB1_DIV(__VALUE__) (((__VALUE__) == LL_RCC_APB1_DIV_1) \
                                      || ((__VALUE__) == LL_RCC_APB1_DIV_2) \
                                      || ((__VALUE__) == LL_RCC_APB1_DIV_4) \
                                      || ((__VALUE__) == LL_RCC_APB1_DIV_8) \
                                      || ((__VALUE__) == LL_RCC_APB1_DIV_16))

#define IS_LL_UTILS_APB2_DIV(__VALUE__) (((__VALUE__) == LL_RCC_APB2_DIV_1) \
                                      || ((__VALUE__) == LL_RCC_APB2_DIV_2) \
                                      || ((__VALUE__) == LL_RCC_APB2_DIV_4) \
                                      || ((__VALUE__) == LL_RCC_APB2_DIV_8) \
                                      || ((__VALUE__) == LL_RCC_APB2_DIV_16))

#define IS_LL_UTILS_PLLMUL_VALUE(__VALUE__) (((__VALUE__) == LL_RCC_PLL_MUL_3) \
                                          || ((__VALUE__) == LL_RCC_PLL_MUL_4) \
                                          || ((__VALUE__) == LL_RCC_PLL_MUL_6) \
                                          || ((__VALUE__) == LL_RCC_PLL_MUL_8) \
                                          || ((__VALUE__) == LL_RCC_PLL_MUL_12) \
                                          || ((__VALUE__) == LL_RCC_PLL_MUL_16) \
                                          || ((__VALUE__) == LL_RCC_PLL_MUL_24) \
                                          || ((__VALUE__) == LL_RCC_PLL_MUL_32) \
                                          || ((__VALUE__) == LL_RCC_PLL_MUL_48))

#define IS_LL_UTILS_PLLDIV_VALUE(__VALUE__) (((__VALUE__) == LL_RCC_PLL_DIV_2) || ((__VALUE__) == LL_RCC_PLL_DIV_3) || \
                                             ((__VALUE__) == LL_RCC_PLL_DIV_4))

#define IS_LL_UTILS_PLLVCO_OUTPUT(__VALUE__) ((LL_PWR_GetRegulVoltageScaling() == LL_PWR_REGU_VOLTAGE_SCALE1) ? ((__VALUE__) <= UTILS_PLLVCO_OUTPUT_SCALE1) : \
                                             ((LL_PWR_GetRegulVoltageScaling() == LL_PWR_REGU_VOLTAGE_SCALE2) ? ((__VALUE__) <= UTILS_PLLVCO_OUTPUT_SCALE2) : \
                                             ((__VALUE__) <= UTILS_PLLVCO_OUTPUT_SCALE3)))

#define IS_LL_UTILS_PLL_FREQUENCY(__VALUE__) ((LL_PWR_GetRegulVoltageScaling() == LL_PWR_REGU_VOLTAGE_SCALE1) ? ((__VALUE__) <= UTILS_MAX_FREQUENCY_SCALE1) : \
                                             ((LL_PWR_GetRegulVoltageScaling() == LL_PWR_REGU_VOLTAGE_SCALE2) ? ((__VALUE__) <= UTILS_MAX_FREQUENCY_SCALE2) : \
                                             ((__VALUE__) <= UTILS_MAX_FREQUENCY_SCALE3)))

#define IS_LL_UTILS_HSE_BYPASS(__STATE__) (((__STATE__) == LL_UTILS_HSEBYPASS_ON) \
                                        || ((__STATE__) == LL_UTILS_HSEBYPASS_OFF))

#define IS_LL_UTILS_HSE_FREQUENCY(__FREQUENCY__) (((__FREQUENCY__) >= UTILS_HSE_FREQUENCY_MIN) && ((__FREQUENCY__) <= UTILS_HSE_FREQUENCY_MAX))
/**
  * @}
  */
/* Private function prototypes -----------------------------------------------*/
/** @defgroup UTILS_LL_Private_Functions UTILS Private functions
  * @{
  */
static uint32_t    UTILS_GetPLLOutputFrequency(uint32_t PLL_InputFrequency,
                                               LL_UTILS_PLLInitTypeDef *UTILS_PLLInitStruct);
static ErrorStatus UTILS_EnablePLLAndSwitchSystem(uint32_t SYSCLK_Frequency, LL_UTILS_ClkInitTypeDef *UTILS_ClkInitStruct);
static ErrorStatus UTILS_PLL_IsBusy(void);
/**
  * @}
  */

/* Exported functions --------------------------------------------------------*/
/** @addtogroup UTILS_LL_Exported_Functions
  * @{
  */

/** @addtogroup UTILS_LL_EF_DELAY
  * @{
  */

/**
  * @brief  This function configures the Cortex-M SysTick source to have 1ms time base.
  * @note   When a RTOS is used, it is recommended to avoid changing the Systick
  *         configuration by calling this function, for a delay use rather osDelay RTOS service.
  * @param  HCLKFrequency HCLK frequency in Hz
  * @note   HCLK frequency can be calculated thanks to RCC helper macro or function @ref LL_RCC_GetSystemClocksFreq
  * @retval None
  */
void LL_Init1msTick(uint32_t HCLKFrequency)
{
  /* Use frequency provided in argument */
  LL_InitTick(HCLKFrequency, 1000U);
}

/**
  * @brief  This function provides accurate delay (in milliseconds) based
  *         on SysTick counter flag
  * @note   When a RTOS is used, it is recommended to avoid using blocking delay
  *         and use rather osDelay service.
  * @note   To respect 1ms timebase, user should call @ref LL_Init1msTick function which
  *         will configure Systick to 1ms
  * @param  Delay specifies the delay time length, in milliseconds.
  * @retval None
  */
void LL_mDelay(uint32_t Delay)
{
  __IO uint32_t  tmp = SysTick->CTRL;  /* Clear the COUNTFLAG first */
  /* Add this code to indicate that local variable is not used */
  ((void)tmp);

  /* Add a period to guaranty minimum wait */
  if (Delay < LL_MAX_DELAY)
  {
    Delay++;
  }

  while (Delay)
  {
    if ((SysTick->CTRL & SysTick_CTRL_COUNTFLAG_Msk) != 0U)
    {
      Delay--;
    }
  }
}

/**
  * @}
  */

/** @addtogroup UTILS_EF_SYSTEM
  *  @brief    System Configuration functions
  *
  @verbatim
 ===============================================================================
           ##### System Configuration functions #####
 ===============================================================================
    [..]
         System, AHB and APB buses clocks configuration

         (+) The maximum frequency of the SYSCLK, HCLK, PCLK1 and PCLK2 is 32000000 Hz.
  @endverbatim
  @internal
             Depending on the device voltage range, the maximum frequency should be
             adapted accordingly:
             (++) +----------------------------------------------------------------+
             (++) |  Wait states  |                HCLK clock frequency (MHz)      |
             (++) |               |------------------------------------------------|
             (++) |   (Latency)   |            voltage range       | voltage range |
             (++) |               |            1.65 V - 3.6 V      | 2.0 V - 3.6 V |
             (++) |               |----------------|---------------|---------------|
             (++) |               |  VCORE = 1.2 V | VCORE = 1.5 V | VCORE = 1.8 V |
             (++) |-------------- |----------------|---------------|---------------|
             (++) |0WS(1CPU cycle)|0 < HCLK <= 2   |0 < HCLK <= 8  |0 < HCLK <= 16 |
             (++) |---------------|----------------|---------------|---------------|
             (++) |1WS(2CPU cycle)|2 < HCLK <= 4   |8 < HCLK <= 16 |16 < HCLK <= 32|
             (++) +----------------------------------------------------------------+
  @endinternal
  * @{
  */

/**
  * @brief  This function sets directly SystemCoreClock CMSIS variable.
  * @note   Variable can be calculated also through SystemCoreClockUpdate function.
  * @param  HCLKFrequency HCLK frequency in Hz (can be calculated thanks to RCC helper macro)
  * @retval None
  */
void LL_SetSystemCoreClock(uint32_t HCLKFrequency)
{
  /* HCLK clock frequency */
  SystemCoreClock = HCLKFrequency;
}

/**
  * @brief  Update number of Flash wait states in line with new frequency and current
            voltage range.
  * @param  Frequency  HCLK frequency
  * @retval An ErrorStatus enumeration value:
  *          - SUCCESS: Latency has been modified
  *          - ERROR: Latency cannot be modified
  */
ErrorStatus LL_SetFlashLatency(uint32_t Frequency)
{
  uint32_t timeout;
  uint32_t getlatency;
  uint32_t latency;
  ErrorStatus status = SUCCESS;

  /* Frequency cannot be equal to 0 */
  if ((Frequency == 0U) || (Frequency > UTILS_MAX_FREQUENCY_SCALE1))
  {
    status = ERROR;
  }
  else
  {
    if (LL_PWR_GetRegulVoltageScaling() == LL_PWR_REGU_VOLTAGE_SCALE1)
    {
      if (Frequency > UTILS_SCALE1_LATENCY1_FREQ)
      {
        /* 16 < HCLK <= 32 => 1WS (2 CPU cycles) */
        latency = LL_FLASH_LATENCY_1;
      }
      else
      {
        /* else HCLK < 16MHz default LL_FLASH_LATENCY_0 0WS */
        latency = LL_FLASH_LATENCY_0;
      }
    }
    else if (LL_PWR_GetRegulVoltageScaling() == LL_PWR_REGU_VOLTAGE_SCALE2)
    {
      if (Frequency > UTILS_SCALE2_LATENCY1_FREQ)
      {
        /* 8 < HCLK <= 16 => 1WS (2 CPU cycles) */
        latency = LL_FLASH_LATENCY_1;
      }
      else
      {
        /* else HCLK < 8MHz default LL_FLASH_LATENCY_0 0WS */
        latency = LL_FLASH_LATENCY_0;
      }
    }
    else
    {
      if (Frequency > UTILS_SCALE3_LATENCY1_FREQ)
      {
        /* 2 < HCLK <= 4 => 1WS (2 CPU cycles) */
        latency = LL_FLASH_LATENCY_1;
      }
      else
      {
        /* else HCLK < 2MHz default LL_FLASH_LATENCY_0 0WS */
        latency = LL_FLASH_LATENCY_0;
      }
    }

    if (status != ERROR)
    {
      LL_FLASH_SetLatency(latency);

      /* Check that the new number of wait states is taken into account to access the Flash
           memory by reading the FLASH_ACR register */
      timeout = 2;
      do
      {
      /* Wait for Flash latency to be updated */
      getlatency = LL_FLASH_GetLatency();
      timeout--;
      } while ((getlatency != latency) && (timeout > 0));

      if(getlatency != latency)
      {
        status = ERROR;
      }
    }
  }
  return status;
}

/**
  * @brief  This function configures system clock with HSI as clock source of the PLL
  * @note   The application need to ensure that PLL is disabled.
  * @note   Function is based on the following formula:
  *         - PLL output frequency = ((HSI frequency * PLLMul) / PLLDiv)
  *         - PLLMul: The application software must set correctly the PLL multiplication factor to ensure
  *           - PLLVCO does not exceed 96 MHz when the product is in range 1,
  *           - PLLVCO does not exceed 48 MHz when the product is in range 2,
  *           - PLLVCO does not exceed 24 MHz when the product is in range 3
  * @note   FLASH latency can be modified through this function.
  * @param  UTILS_PLLInitStruct pointer to a @ref LL_UTILS_PLLInitTypeDef structure that contains
  *                             the configuration information for the PLL.
  * @param  UTILS_ClkInitStruct pointer to a @ref LL_UTILS_ClkInitTypeDef structure that contains
  *                             the configuration information for the BUS prescalers.
  * @retval An ErrorStatus enumeration value:
  *          - SUCCESS: Max frequency configuration done
  *          - ERROR: Max frequency configuration not done
  */
ErrorStatus LL_PLL_ConfigSystemClock_HSI(LL_UTILS_PLLInitTypeDef *UTILS_PLLInitStruct,
                                         LL_UTILS_ClkInitTypeDef *UTILS_ClkInitStruct)
{
  ErrorStatus status = SUCCESS;
  uint32_t pllfreq = 0U;

  /* Check if one of the PLL is enabled */
  if (UTILS_PLL_IsBusy() == SUCCESS)
  {
    /* Calculate the new PLL output frequency */
    pllfreq = UTILS_GetPLLOutputFrequency(HSI_VALUE, UTILS_PLLInitStruct);

    /* Enable HSI if not enabled */
    if (LL_RCC_HSI_IsReady() != 1U)
    {
      LL_RCC_HSI_Enable();
      while (LL_RCC_HSI_IsReady() != 1U)
      {
        /* Wait for HSI ready */
      }
    }

    /* Configure PLL */
    LL_RCC_PLL_ConfigDomain_SYS(LL_RCC_PLLSOURCE_HSI, UTILS_PLLInitStruct->PLLMul, UTILS_PLLInitStruct->PLLDiv);

    /* Enable PLL and switch system clock to PLL */
    status = UTILS_EnablePLLAndSwitchSystem(pllfreq, UTILS_ClkInitStruct);
  }
  else
  {
    /* Current PLL configuration cannot be modified */
    status = ERROR;
  }

  return status;
}

/**
  * @brief  This function configures system clock with HSE as clock source of the PLL
  * @note   The application need to ensure that PLL is disabled.
  * @note   Function is based on the following formula:
  *         - PLL output frequency = ((HSE frequency * PLLMul) / PLLDiv)
  *         - PLLMul: The application software must set correctly the PLL multiplication factor to to ensure
  *           - PLLVCO does not exceed 96 MHz when the product is in range 1,
  *           - PLLVCO does not exceed 48 MHz when the product is in range 2,
  *           - PLLVCO does not exceed 24 MHz when the product is in range 3
  * @note   FLASH latency can be modified through this function.
  * @param  HSEFrequency Value between Min_Data = 1000000 and Max_Data = 24000000
  * @param  HSEBypass This parameter can be one of the following values:
  *         @arg @ref LL_UTILS_HSEBYPASS_ON
  *         @arg @ref LL_UTILS_HSEBYPASS_OFF
  * @param  UTILS_PLLInitStruct pointer to a @ref LL_UTILS_PLLInitTypeDef structure that contains
  *                             the configuration information for the PLL.
  * @param  UTILS_ClkInitStruct pointer to a @ref LL_UTILS_ClkInitTypeDef structure that contains
  *                             the configuration information for the BUS prescalers.
  * @retval An ErrorStatus enumeration value:
  *          - SUCCESS: Max frequency configuration done
  *          - ERROR: Max frequency configuration not done
  */
ErrorStatus LL_PLL_ConfigSystemClock_HSE(uint32_t HSEFrequency, uint32_t HSEBypass,
                                         LL_UTILS_PLLInitTypeDef *UTILS_PLLInitStruct, LL_UTILS_ClkInitTypeDef *UTILS_ClkInitStruct)
{
  ErrorStatus status = SUCCESS;
  uint32_t pllfreq = 0U;

  /* Check the parameters */
  assert_param(IS_LL_UTILS_HSE_FREQUENCY(HSEFrequency));
  assert_param(IS_LL_UTILS_HSE_BYPASS(HSEBypass));

  /* Check if one of the PLL is enabled */
  if (UTILS_PLL_IsBusy() == SUCCESS)
  {
    /* Calculate the new PLL output frequency */
    pllfreq = UTILS_GetPLLOutputFrequency(HSEFrequency, UTILS_PLLInitStruct);

    /* Enable HSE if not enabled */
    if (LL_RCC_HSE_IsReady() != 1U)
    {
      /* Check if need to enable HSE bypass feature or not */
      if (HSEBypass == LL_UTILS_HSEBYPASS_ON)
      {
        LL_RCC_HSE_EnableBypass();
      }
      else
      {
        LL_RCC_HSE_DisableBypass();
      }

      /* Enable HSE */
      LL_RCC_HSE_Enable();
      while (LL_RCC_HSE_IsReady() != 1U)
      {
        /* Wait for HSE ready */
      }
    }

      /* Configure PLL */
      LL_RCC_PLL_ConfigDomain_SYS(LL_RCC_PLLSOURCE_HSE, UTILS_PLLInitStruct->PLLMul, UTILS_PLLInitStruct->PLLDiv);

    /* Enable PLL and switch system clock to PLL */
    status = UTILS_EnablePLLAndSwitchSystem(pllfreq, UTILS_ClkInitStruct);
  }
  else
  {
    /* Current PLL configuration cannot be modified */
    status = ERROR;
  }

  return status;
}

/**
  * @}
  */

/**
  * @}
  */

/** @addtogroup UTILS_LL_Private_Functions
  * @{
  */
/**
  * @brief  Function to check that PLL can be modified
  * @param  PLL_InputFrequency  PLL input frequency (in Hz)
  * @param  UTILS_PLLInitStruct pointer to a @ref LL_UTILS_PLLInitTypeDef structure that contains
  *                             the configuration information for the PLL.
  * @retval PLL output frequency (in Hz)
  */
static uint32_t UTILS_GetPLLOutputFrequency(uint32_t PLL_InputFrequency, LL_UTILS_PLLInitTypeDef *UTILS_PLLInitStruct)
{
  uint32_t pllfreq = 0U;

  /* Check the parameters */
  assert_param(IS_LL_UTILS_PLLMUL_VALUE(UTILS_PLLInitStruct->PLLMul));
  assert_param(IS_LL_UTILS_PLLDIV_VALUE(UTILS_PLLInitStruct->PLLDiv));

  /* Check different PLL parameters according to RM                          */
  /* The application software must set correctly the PLL multiplication factor to avoid exceeding
     96 MHz as PLLVCO when the product is in range 1,
     48 MHz as PLLVCO when the product is in range 2,
     24 MHz when the product is in range 3. */
  pllfreq = PLL_InputFrequency * (PLLMulTable[UTILS_PLLInitStruct->PLLMul >> RCC_CFGR_PLLMUL_Pos]);
  assert_param(IS_LL_UTILS_PLLVCO_OUTPUT(pllfreq));

  /* The application software must set correctly the PLL multiplication factor to avoid exceeding
     maximum frequency 32000000 in range 1 */
  pllfreq = pllfreq / ((UTILS_PLLInitStruct->PLLDiv >> RCC_CFGR_PLLDIV_Pos)+1U);
  assert_param(IS_LL_UTILS_PLL_FREQUENCY(pllfreq));

  return pllfreq;
}

/**
  * @brief  Function to check that PLL can be modified
  * @retval An ErrorStatus enumeration value:
  *          - SUCCESS: PLL modification can be done
  *          - ERROR: PLL is busy
  */
static ErrorStatus UTILS_PLL_IsBusy(void)
{
  ErrorStatus status = SUCCESS;

  /* Check if PLL is busy*/
  if (LL_RCC_PLL_IsReady() != 0U)
  {
    /* PLL configuration cannot be modified */
    status = ERROR;
  }


  return status;
}

/**
  * @brief  Function to enable PLL and switch system clock to PLL
  * @param  SYSCLK_Frequency SYSCLK frequency
  * @param  UTILS_ClkInitStruct pointer to a @ref LL_UTILS_ClkInitTypeDef structure that contains
  *                             the configuration information for the BUS prescalers.
  * @retval An ErrorStatus enumeration value:
  *          - SUCCESS: No problem to switch system to PLL
  *          - ERROR: Problem to switch system to PLL
  */
static ErrorStatus UTILS_EnablePLLAndSwitchSystem(uint32_t SYSCLK_Frequency, LL_UTILS_ClkInitTypeDef *UTILS_ClkInitStruct)
{
  ErrorStatus status = SUCCESS;
  uint32_t hclk_frequency = 0U;

  assert_param(IS_LL_UTILS_SYSCLK_DIV(UTILS_ClkInitStruct->AHBCLKDivider));
  assert_param(IS_LL_UTILS_APB1_DIV(UTILS_ClkInitStruct->APB1CLKDivider));
  assert_param(IS_LL_UTILS_APB2_DIV(UTILS_ClkInitStruct->APB2CLKDivider));

  /* Calculate HCLK frequency */
  hclk_frequency = __LL_RCC_CALC_HCLK_FREQ(SYSCLK_Frequency, UTILS_ClkInitStruct->AHBCLKDivider);

  /* Increasing the number of wait states because of higher CPU frequency */
  if (SystemCoreClock < hclk_frequency)
  {
    /* Set FLASH latency to highest latency */
    status = LL_SetFlashLatency(hclk_frequency);
  }

  /* Update system clock configuration */
  if (status == SUCCESS)
  {
    /* Enable PLL */
    LL_RCC_PLL_Enable();
    while (LL_RCC_PLL_IsReady() != 1U)
    {
      /* Wait for PLL ready */
    }

    /* Sysclk activation on the main PLL */
    LL_RCC_SetAHBPrescaler(UTILS_ClkInitStruct->AHBCLKDivider);
    LL_RCC_SetSysClkSource(LL_RCC_SYS_CLKSOURCE_PLL);
    while (LL_RCC_GetSysClkSource() != LL_RCC_SYS_CLKSOURCE_STATUS_PLL)
    {
      /* Wait for system clock switch to PLL */
    }

    /* Set APB1 & APB2 prescaler*/
    LL_RCC_SetAPB1Prescaler(UTILS_ClkInitStruct->APB1CLKDivider);
    LL_RCC_SetAPB2Prescaler(UTILS_ClkInitStruct->APB2CLKDivider);
  }

  /* Decreasing the number of wait states because of lower CPU frequency */
  if (SystemCoreClock > hclk_frequency)
  {
    /* Set FLASH latency to lowest latency */
    status = LL_SetFlashLatency(hclk_frequency);
  }

  /* Update SystemCoreClock variable */
  if (status == SUCCESS)
  {
    LL_SetSystemCoreClock(hclk_frequency);
  }

  return status;
}

/**
  * @}
  */

/**
  * @}
  */

/**
  * @}
  */