system_stm32h7xx.c

/**
  ******************************************************************************
  * @file    system_stm32h7xx.c
  * @author  MCD Application Team
  * @version V1.2.0
  * @date    29-December-2017
  * @brief   CMSIS Cortex-M 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_stm32h7xx.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(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.
  *
  ******************************************************************************
  */

/** @addtogroup CMSIS
  * @{
  */

/** @addtogroup stm32h7xx_system
  * @{
  */  
  
/** @addtogroup STM32H7xx_System_Private_Includes
  * @{
  */

#include "stm32h7xx_hal.h"

/**
  * @}
  */

/** @addtogroup STM32H7xx_System_Private_TypesDefinitions
  * @{
  */

/**
  * @}
  */

/** @addtogroup STM32H7xx_System_Private_Defines
  * @{
  */

/************************* Miscellaneous Configuration ************************/
/*!< Uncomment the following line if you need to relocate your vector Table in
     Internal SRAM. */
/* #define VECT_TAB_SRAM */
#define VECT_TAB_OFFSET  0x00       /*!< Vector Table base offset field. 
                                      This value must be a multiple of 0x200. */
/******************************************************************************/

/**
  * @}
  */

/** @addtogroup STM32H7xx_System_Private_Macros
  * @{
  */

/**
  * @}
  */

/** @addtogroup STM32H7xx_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 = 64000000;
  uint32_t SystemD2Clock = 64000000;
  const  uint8_t D1CorePrescTable[16] = {0, 0, 0, 0, 1, 2, 3, 4, 1, 2, 3, 4, 6, 7, 8, 9};

/**
  * @}
  */

/** @addtogroup STM32H7xx_System_Private_Functions
  * @{
  */

/**
  * @brief  Setup the microcontroller system
  *         Initialize the FPU setting, vector table location.
  * @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 |= RCC_CR_HSION;
  
  /* Reset CFGR register */
  RCC->CFGR = 0x00000000;

  /* Reset HSEON, CSSON , CSION,RC48ON, CSIKERON PLL1ON, PLL2ON and PLL3ON bits */
  RCC->CR &= (uint32_t)0xEAF6ED7F;

  /* Reset D1CFGR register */
  RCC->D1CFGR = 0x00000000;

  /* Reset D2CFGR register */
  RCC->D2CFGR = 0x00000000;
  
  /* Reset D3CFGR register */
  RCC->D3CFGR = 0x00000000;

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

  /* Reset PLLCFGR register */
  RCC->PLLCFGR = 0x00000000;
  /* Reset PLL1DIVR register */
  RCC->PLL1DIVR = 0x00000000;
  /* Reset PLL1FRACR register */
  RCC->PLL1FRACR = 0x00000000;

  /* Reset PLL2DIVR register */
  RCC->PLL2DIVR = 0x00000000;

  /* Reset PLL2FRACR register */
  
  RCC->PLL2FRACR = 0x00000000;
  /* Reset PLL3DIVR register */
  RCC->PLL3DIVR = 0x00000000;

  /* Reset PLL3FRACR register */
  RCC->PLL3FRACR = 0x00000000;
  
  /* Reset HSEBYP bit */
  RCC->CR &= (uint32_t)0xFFFBFFFF;

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

  /* Change  the switch matrix read issuing capability to 1 for the AXI SRAM target (Target 7) */
  *((__IO uint32_t*)0x51008108) = 0x00000001;

  /* Configure the Vector Table location add offset address ------------------*/
#ifdef VECT_TAB_SRAM
  SCB->VTOR = D1_AXISRAM_BASE  | VECT_TAB_OFFSET;       /* Vector Table Relocation in Internal SRAM */
#else
  SCB->VTOR = FLASH_BANK1_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 , it can
  *         be used by the user application to setup the SysTick timer or configure
  *         other parameters.
  *           
  * @note   Each time the core clock 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 CSI, SystemCoreClock will contain the CSI_VALUE(*)                                 
  *           - 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 CSI_VALUE(*),
  *             HSI_VALUE(**) or HSE_VALUE(***) multiplied/divided by the PLL factors.
  *
  *         (*) CSI_VALUE is a constant defined in stm32h7xx_hal.h file (default value
  *             4 MHz) but the real value may vary depending on the variations
  *             in voltage and temperature.        
  *         (**) HSI_VALUE is a constant defined in stm32h7xx_hal.h file (default value
  *             64 MHz) but the real value may vary depending on the variations
  *             in voltage and temperature.   
  *    
  *         (***)HSE_VALUE is a constant defined in stm32h7xx_hal.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 pllp = 2, pllsource = 0, pllm = 2 ,tmp, pllfracen  =0 , hsivalue = 0;
float fracn1, pllvco = 0 ;

  /* Get SYSCLK source -------------------------------------------------------*/

  switch (RCC->CFGR & RCC_CFGR_SWS)
  {
  case 0x00:  /* HSI used as system clock source */

   SystemCoreClock = (uint32_t) (HSI_VALUE >> ((RCC->CR & RCC_CR_HSIDIV)>> 3));

    break;

  case 0x08:  /* CSI used as system clock  source */
    SystemCoreClock = CSI_VALUE;
    break;

  case 0x10:  /* HSE used as system clock  source */
    SystemCoreClock = HSE_VALUE;
    break;

  case 0x18:  /* PLL1 used as system clock  source */

    /* PLL_VCO = (HSE_VALUE or HSI_VALUE or CSI_VALUE/ PLLM) * PLLN
    SYSCLK = PLL_VCO / PLLR
    */
    pllsource = (RCC->PLLCKSELR & RCC_PLLCKSELR_PLLSRC);
    pllm = ((RCC->PLLCKSELR & RCC_PLLCKSELR_DIVM1)>> 4)  ;
    pllfracen = RCC->PLLCFGR & RCC_PLLCFGR_PLL1FRACEN;
    fracn1 = (pllfracen* ((RCC->PLL1FRACR & RCC_PLL1FRACR_FRACN1)>> 3));
    switch (pllsource)
    {

    case 0x00:  /* HSI used as PLL clock source */
      hsivalue = (HSI_VALUE >> ((RCC->CR & RCC_CR_HSIDIV)>> 3)) ;
      pllvco = (hsivalue/ pllm) * ((RCC->PLL1DIVR & RCC_PLL1DIVR_N1) + (fracn1/0x2000) +1 );
      break;

    case 0x01:  /* CSI used as PLL clock source */
      pllvco = (CSI_VALUE / pllm) * ((RCC->PLL1DIVR & RCC_PLL1DIVR_N1) + (fracn1/0x2000) +1 );
      break;

    case 0x02:  /* HSE used as PLL clock source */
      pllvco = (HSE_VALUE / pllm) * ((RCC->PLL1DIVR & RCC_PLL1DIVR_N1) + (fracn1/0x2000) +1 );
      break;

    default:
      pllvco = (CSI_VALUE / pllm) * ((RCC->PLL1DIVR & RCC_PLL1DIVR_N1) + (fracn1/0x2000) +1 );
      break;
    }
    pllp = (((RCC->PLL1DIVR & RCC_PLL1DIVR_P1) >>9) + 1 ) ;
    SystemCoreClock = (uint32_t) (pllvco/pllp);
    break;

  default:
    SystemCoreClock = CSI_VALUE;
    break;
  }
  
  /* Compute HCLK frequency --------------------------------------------------*/
  /* Get HCLK prescaler */
  tmp = D1CorePrescTable[(RCC->D1CFGR & RCC_D1CFGR_D1CPRE)>> POSITION_VAL(RCC_D1CFGR_D1CPRE_0)];
  /* HCLK frequency */
  SystemCoreClock >>= tmp;
}
  
/**
  * @}
  */

/**
  * @}
  */

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