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259 lines
8.9 KiB
259 lines
8.9 KiB
/** |
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****************************************************************************** |
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* @file system_stm32f7xx.c |
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* @author MCD Application Team |
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* @brief CMSIS Cortex-M7 Device Peripheral Access Layer System Source File. |
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* |
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* This file provides two functions and one global variable to be called from |
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* user application: |
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* - SystemInit(): This function is called at startup just after reset and |
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* before branch to main program. This call is made inside |
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* the "startup_stm32f7xx.s" file. |
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* |
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* - SystemCoreClock variable: Contains the core clock (HCLK), it can be used |
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* by the user application to setup the SysTick |
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* timer or configure other parameters. |
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* |
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* - SystemCoreClockUpdate(): Updates the variable SystemCoreClock and must |
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* be called whenever the core clock is changed |
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* during program execution. |
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* |
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* |
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****************************************************************************** |
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* @attention |
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* |
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* Copyright (c) 2016 STMicroelectronics. |
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* All rights reserved. |
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* |
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* This software is licensed under terms that can be found in the LICENSE file |
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* in the root directory of this software component. |
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* If no LICENSE file comes with this software, it is provided AS-IS. |
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* |
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****************************************************************************** |
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*/ |
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/** @addtogroup CMSIS |
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* @{ |
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*/ |
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/** @addtogroup stm32f7xx_system |
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* @{ |
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*/ |
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/** @addtogroup STM32F7xx_System_Private_Includes |
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* @{ |
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*/ |
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#include "stm32f7xx.h" |
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#if !defined (HSE_VALUE) |
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#define HSE_VALUE ((uint32_t)25000000) /*!< Default value of the External oscillator in Hz */ |
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#endif /* HSE_VALUE */ |
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#if !defined (HSI_VALUE) |
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#define HSI_VALUE ((uint32_t)16000000) /*!< Value of the Internal oscillator in Hz*/ |
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#endif /* HSI_VALUE */ |
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/** |
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* @} |
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*/ |
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/** @addtogroup STM32F7xx_System_Private_TypesDefinitions |
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* @{ |
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*/ |
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/** |
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* @} |
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*/ |
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/** @addtogroup STM32F7xx_System_Private_Defines |
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* @{ |
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*/ |
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/************************* Miscellaneous Configuration ************************/ |
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/* Note: Following vector table addresses must be defined in line with linker |
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configuration. */ |
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/*!< Uncomment the following line if you need to relocate the vector table |
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anywhere in Flash or Sram, else the vector table is kept at the automatic |
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remap of boot address selected */ |
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/* #define USER_VECT_TAB_ADDRESS */ |
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#if defined(USER_VECT_TAB_ADDRESS) |
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/*!< Uncomment the following line if you need to relocate your vector Table |
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in Sram else user remap will be done in Flash. */ |
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/* #define VECT_TAB_SRAM */ |
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#if defined(VECT_TAB_SRAM) |
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#define VECT_TAB_BASE_ADDRESS RAMDTCM_BASE /*!< Vector Table base address field. |
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This value must be a multiple of 0x200. */ |
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#define VECT_TAB_OFFSET 0x00000000U /*!< Vector Table base offset field. |
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This value must be a multiple of 0x200. */ |
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#else |
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#define VECT_TAB_BASE_ADDRESS FLASH_BASE /*!< Vector Table base address field. |
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This value must be a multiple of 0x200. */ |
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#define VECT_TAB_OFFSET 0x00000000U /*!< Vector Table base offset field. |
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This value must be a multiple of 0x200. */ |
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#endif /* VECT_TAB_SRAM */ |
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#endif /* USER_VECT_TAB_ADDRESS */ |
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/******************************************************************************/ |
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/** |
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* @} |
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*/ |
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/** @addtogroup STM32F7xx_System_Private_Macros |
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* @{ |
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*/ |
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/** |
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* @} |
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*/ |
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/** @addtogroup STM32F7xx_System_Private_Variables |
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* @{ |
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*/ |
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/* This variable is updated in three ways: |
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1) by calling CMSIS function SystemCoreClockUpdate() |
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2) by calling HAL API function HAL_RCC_GetHCLKFreq() |
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3) each time HAL_RCC_ClockConfig() is called to configure the system clock frequency |
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Note: If you use this function to configure the system clock; then there |
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is no need to call the 2 first functions listed above, since SystemCoreClock |
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variable is updated automatically. |
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*/ |
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uint32_t SystemCoreClock = 16000000; |
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const uint8_t AHBPrescTable[16] = {0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 6, 7, 8, 9}; |
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const uint8_t APBPrescTable[8] = {0, 0, 0, 0, 1, 2, 3, 4}; |
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/** |
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* @} |
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*/ |
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/** @addtogroup STM32F7xx_System_Private_FunctionPrototypes |
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* @{ |
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*/ |
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/** |
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* @} |
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*/ |
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/** @addtogroup STM32F7xx_System_Private_Functions |
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* @{ |
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*/ |
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/** |
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* @brief Setup the microcontroller system |
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* Initialize the Embedded Flash Interface, the PLL and update the |
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* SystemFrequency variable. |
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* @param None |
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* @retval None |
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*/ |
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void SystemInit(void) |
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{ |
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/* FPU settings ------------------------------------------------------------*/ |
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#if (__FPU_PRESENT == 1) && (__FPU_USED == 1) |
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SCB->CPACR |= ((3UL << 10*2)|(3UL << 11*2)); /* set CP10 and CP11 Full Access */ |
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#endif |
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/* Configure the Vector Table location -------------------------------------*/ |
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#if defined(USER_VECT_TAB_ADDRESS) |
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SCB->VTOR = VECT_TAB_BASE_ADDRESS | VECT_TAB_OFFSET; /* Vector Table Relocation in Internal SRAM */ |
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#endif /* USER_VECT_TAB_ADDRESS */ |
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} |
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/** |
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* @brief Update SystemCoreClock variable according to Clock Register Values. |
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* The SystemCoreClock variable contains the core clock (HCLK), it can |
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* be used by the user application to setup the SysTick timer or configure |
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* other parameters. |
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* |
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* @note Each time the core clock (HCLK) changes, this function must be called |
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* to update SystemCoreClock variable value. Otherwise, any configuration |
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* based on this variable will be incorrect. |
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* |
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* @note - The system frequency computed by this function is not the real |
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* frequency in the chip. It is calculated based on the predefined |
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* constant and the selected clock source: |
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* |
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* - If SYSCLK source is HSI, SystemCoreClock will contain the HSI_VALUE(*) |
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* |
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* - If SYSCLK source is HSE, SystemCoreClock will contain the HSE_VALUE(**) |
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* |
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* - If SYSCLK source is PLL, SystemCoreClock will contain the HSE_VALUE(**) |
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* or HSI_VALUE(*) multiplied/divided by the PLL factors. |
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* |
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* (*) HSI_VALUE is a constant defined in stm32f7xx_hal_conf.h file (default value |
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* 16 MHz) but the real value may vary depending on the variations |
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* in voltage and temperature. |
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* |
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* (**) HSE_VALUE is a constant defined in stm32f7xx_hal_conf.h file (default value |
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* 25 MHz), user has to ensure that HSE_VALUE is same as the real |
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* frequency of the crystal used. Otherwise, this function may |
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* have wrong result. |
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* |
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* - The result of this function could be not correct when using fractional |
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* value for HSE crystal. |
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* |
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* @param None |
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* @retval None |
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*/ |
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void SystemCoreClockUpdate(void) |
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{ |
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uint32_t tmp = 0, pllvco = 0, pllp = 2, pllsource = 0, pllm = 2; |
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/* Get SYSCLK source -------------------------------------------------------*/ |
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tmp = RCC->CFGR & RCC_CFGR_SWS; |
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switch (tmp) |
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{ |
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case 0x00: /* HSI used as system clock source */ |
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SystemCoreClock = HSI_VALUE; |
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break; |
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case 0x04: /* HSE used as system clock source */ |
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SystemCoreClock = HSE_VALUE; |
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break; |
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case 0x08: /* PLL used as system clock source */ |
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/* PLL_VCO = (HSE_VALUE or HSI_VALUE / PLL_M) * PLL_N |
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SYSCLK = PLL_VCO / PLL_P |
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*/ |
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pllsource = (RCC->PLLCFGR & RCC_PLLCFGR_PLLSRC) >> 22; |
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pllm = RCC->PLLCFGR & RCC_PLLCFGR_PLLM; |
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if (pllsource != 0) |
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{ |
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/* HSE used as PLL clock source */ |
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pllvco = (HSE_VALUE / pllm) * ((RCC->PLLCFGR & RCC_PLLCFGR_PLLN) >> 6); |
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} |
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else |
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{ |
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/* HSI used as PLL clock source */ |
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pllvco = (HSI_VALUE / pllm) * ((RCC->PLLCFGR & RCC_PLLCFGR_PLLN) >> 6); |
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} |
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pllp = (((RCC->PLLCFGR & RCC_PLLCFGR_PLLP) >>16) + 1 ) *2; |
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SystemCoreClock = pllvco/pllp; |
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break; |
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default: |
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SystemCoreClock = HSI_VALUE; |
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break; |
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} |
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/* Compute HCLK frequency --------------------------------------------------*/ |
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/* Get HCLK prescaler */ |
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tmp = AHBPrescTable[((RCC->CFGR & RCC_CFGR_HPRE) >> 4)]; |
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/* HCLK frequency */ |
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SystemCoreClock >>= tmp; |
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} |
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/** |
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* @} |
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*/ |
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/** |
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* @} |
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*/ |
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/** |
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* @} |
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*/ |
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/************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/
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