/**
  ******************************************************************************
  * @file    system_stm32f7xx.c
  * @author  MCD Application Team
  * @brief   CMSIS Cortex-M7 Device Peripheral Access Layer System Source File.
  *
  *   This file provides two functions and one global variable to be called from
  *   user application:
  *      - SystemInit(): This function is called at startup just after reset and
  *                      before branch to main program. This call is made inside
  *                      the "startup_stm32f7xx.s" file.
  *
  *      - SystemCoreClock variable: Contains the core clock (HCLK), it can be used
  *                                  by the user application to setup the SysTick
  *                                  timer or configure other parameters.
  *
  *      - SystemCoreClockUpdate(): Updates the variable SystemCoreClock and must
  *                                 be called whenever the core clock is changed
  *                                 during program execution.
  *
  *
  ******************************************************************************
  * @attention
  *
  * <h2><center>&copy; COPYRIGHT 2016 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.
  *
  ******************************************************************************
  */

/** @addtogroup CMSIS
  * @{
  */

/** @addtogroup stm32f7xx_system
  * @{
  */

/** @addtogroup STM32F7xx_System_Private_Includes
  * @{
  */

#include "stm32f7xx.h"

#if !defined  (HSE_VALUE)
#define HSE_VALUE    ((uint32_t)25000000) /*!< Default value of the External oscillator in Hz */
#endif /* HSE_VALUE */

#if !defined  (HSI_VALUE)
#define HSI_VALUE    ((uint32_t)16000000) /*!< Value of the Internal oscillator in Hz*/
#endif /* HSI_VALUE */

/**
  * @}
  */

/** @addtogroup STM32F7xx_System_Private_TypesDefinitions
  * @{
  */

/**
  * @}
  */

/** @addtogroup STM32F7xx_System_Private_Defines
  * @{
  */

/************************* Miscellaneous Configuration ************************/

/*!< Uncomment the following line if you need to relocate your vector Table in
     Internal SRAM. */
/* #define VECT_TAB_SRAM */
#ifndef VECT_TAB_OFFSET
#define VECT_TAB_OFFSET  0x0 /*!< Vector Table base offset field.
                                   This value must be a multiple of 0x200. */
#endif
/******************************************************************************/

/**
  * @}
  */

/** @addtogroup STM32F7xx_System_Private_Macros
  * @{
  */

/**
  * @}
  */

/** @addtogroup STM32F7xx_System_Private_Variables
  * @{
  */

/* This variable is updated in three ways:
    1) by calling CMSIS function SystemCoreClockUpdate()
    2) by calling HAL API function HAL_RCC_GetHCLKFreq()
    3) each time HAL_RCC_ClockConfig() is called to configure the system clock frequency
       Note: If you use this function to configure the system clock; then there
             is no need to call the 2 first functions listed above, since SystemCoreClock
             variable is updated automatically.
*/
uint32_t SystemCoreClock = 16000000;
const uint8_t AHBPrescTable[16] = {0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 6, 7, 8, 9};
const uint8_t APBPrescTable[8] = {0, 0, 0, 0, 1, 2, 3, 4};

/**
  * @}
  */

/** @addtogroup STM32F7xx_System_Private_FunctionPrototypes
  * @{
  */

/**
  * @}
  */

/** @addtogroup STM32F7xx_System_Private_Functions
  * @{
  */

/**
  * @brief  Setup the microcontroller system
  *         Initialize the Embedded Flash Interface, the PLL and update the
  *         SystemFrequency variable.
  * @param  None
  * @retval None
  */
void SystemInit(void)
{
	/* FPU settings ------------------------------------------------------------*/
#if (__FPU_PRESENT == 1) && (__FPU_USED == 1)
	SCB->CPACR |= ((3UL << 10*2)|(3UL << 11*2));  /* set CP10 and CP11 Full Access */
#endif
	/* Reset the RCC clock configuration to the default reset state ------------*/
	/* Set HSION bit */
	RCC->CR |= (uint32_t)0x00000001;

	/* Reset CFGR register */
	RCC->CFGR = 0x00000000;

	/* Reset HSEON, CSSON and PLLON bits */
	RCC->CR &= (uint32_t)0xFEF6FFFF;

	/* Reset PLLCFGR register */
	RCC->PLLCFGR = 0x24003010;

	/* Reset HSEBYP bit */
	RCC->CR &= (uint32_t)0xFFFBFFFF;

	/* Disable all interrupts */
	RCC->CIR = 0x00000000;

	/* Configure the Vector Table location add offset address ------------------*/
#ifdef VECT_TAB_SRAM
	SCB->VTOR = RAMDTCM_BASE | VECT_TAB_OFFSET; /* Vector Table Relocation in Internal SRAM */
#else
	SCB->VTOR = FLASH_BASE | VECT_TAB_OFFSET; /* Vector Table Relocation in Internal FLASH */
#endif
}

/**
   * @brief  Update SystemCoreClock variable according to Clock Register Values.
  *         The SystemCoreClock variable contains the core clock (HCLK), it can
  *         be used by the user application to setup the SysTick timer or configure
  *         other parameters.
  *
  * @note   Each time the core clock (HCLK) changes, this function must be called
  *         to update SystemCoreClock variable value. Otherwise, any configuration
  *         based on this variable will be incorrect.
  *
  * @note   - The system frequency computed by this function is not the real
  *           frequency in the chip. It is calculated based on the predefined
  *           constant and the selected clock source:
  *
  *           - If SYSCLK source is HSI, SystemCoreClock will contain the HSI_VALUE(*)
  *
  *           - If SYSCLK source is HSE, SystemCoreClock will contain the HSE_VALUE(**)
  *
  *           - If SYSCLK source is PLL, SystemCoreClock will contain the HSE_VALUE(**)
  *             or HSI_VALUE(*) multiplied/divided by the PLL factors.
  *
  *         (*) HSI_VALUE is a constant defined in stm32f7xx_hal_conf.h file (default value
  *             16 MHz) but the real value may vary depending on the variations
  *             in voltage and temperature.
  *
  *         (**) HSE_VALUE is a constant defined in stm32f7xx_hal_conf.h file (default value
  *              25 MHz), user has to ensure that HSE_VALUE is same as the real
  *              frequency of the crystal used. Otherwise, this function may
  *              have wrong result.
  *
  *         - The result of this function could be not correct when using fractional
  *           value for HSE crystal.
  *
  * @param  None
  * @retval None
  */
void SystemCoreClockUpdate(void)
{
	uint32_t tmp = 0, pllvco = 0, pllp = 2, pllsource = 0, pllm = 2;

	/* Get SYSCLK source -------------------------------------------------------*/
	tmp = RCC->CFGR & RCC_CFGR_SWS;

	switch (tmp) {
	case 0x00:  /* HSI used as system clock source */
		SystemCoreClock = HSI_VALUE;
		break;
	case 0x04:  /* HSE used as system clock source */
		SystemCoreClock = HSE_VALUE;
		break;
	case 0x08:  /* PLL used as system clock source */

		/* PLL_VCO = (HSE_VALUE or HSI_VALUE / PLL_M) * PLL_N
		   SYSCLK = PLL_VCO / PLL_P
		   */
		pllsource = (RCC->PLLCFGR & RCC_PLLCFGR_PLLSRC) >> 22;
		pllm = RCC->PLLCFGR & RCC_PLLCFGR_PLLM;

		if (pllsource != 0) {
			/* HSE used as PLL clock source */
			pllvco = (HSE_VALUE / pllm) * ((RCC->PLLCFGR & RCC_PLLCFGR_PLLN) >> 6);
		} else {
			/* HSI used as PLL clock source */
			pllvco = (HSI_VALUE / pllm) * ((RCC->PLLCFGR & RCC_PLLCFGR_PLLN) >> 6);
		}

		pllp = (((RCC->PLLCFGR & RCC_PLLCFGR_PLLP) >>16) + 1 ) *2;
		SystemCoreClock = pllvco/pllp;
		break;
	default:
		SystemCoreClock = HSI_VALUE;
		break;
	}
	/* Compute HCLK frequency --------------------------------------------------*/
	/* Get HCLK prescaler */
	tmp = AHBPrescTable[((RCC->CFGR & RCC_CFGR_HPRE) >> 4)];
	/* HCLK frequency */
	SystemCoreClock >>= tmp;
}

/**
  * @}
  */

/**
  * @}
  */

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