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/** ****************************************************************************** * @file system_stm32f1xx.c * @author MCD Application Team * @brief CMSIS Cortex-M3 Device Peripheral Access Layer System Source File. * * 1. This file provides two functions and one global variable to be called from * user application: * - SystemInit(): Setups the system clock (System clock source, PLL Multiplier * factors, AHB/APBx prescalers and Flash settings). * This function is called at startup just after reset and * before branch to main program. This call is made inside * the "startup_stm32f1xx_xx.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. * * 2. After each device reset the HSI (8 MHz) is used as system clock source. * Then SystemInit() function is called, in "startup_stm32f1xx_xx.s" file, to * configure the system clock before to branch to main program. * * 4. The default value of HSE crystal is set to 8 MHz (or 25 MHz, depending on * the product used), refer to "HSE_VALUE". * When HSE is used as system clock source, directly or through PLL, and you * are using different crystal you have to adapt the HSE value to your own * configuration. * ****************************************************************************** * @attention * * <h2><center>&copy; Copyright (c) 2017 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 * ****************************************************************************** */ /** @addtogroup CMSIS * @{ */ /** @addtogroup stm32f1xx_system * @{ */ /** @addtogroup STM32F1xx_System_Private_Includes * @{ */ #include "stm32f1xx.h" /** * @} */ /** @addtogroup STM32F1xx_System_Private_TypesDefinitions * @{ */ /** * @} */ /** @addtogroup STM32F1xx_System_Private_Defines * @{ */ #if !defined (HSE_VALUE) #define HSE_VALUE 8000000U /*!< Default value of the External oscillator in Hz. This value can be provided and adapted by the user application. */ #endif /* HSE_VALUE */ #if !defined (HSI_VALUE) #define HSI_VALUE 8000000U /*!< Default value of the Internal oscillator in Hz. This value can be provided and adapted by the user application. */ #endif /* HSI_VALUE */ /*!< Uncomment the following line if you need to use external SRAM */ #if defined(STM32F100xE) || defined(STM32F101xE) || defined(STM32F101xG) || defined(STM32F103xE) || defined(STM32F103xG) /* #define DATA_IN_ExtSRAM */ #endif /* STM32F100xE || STM32F101xE || STM32F101xG || STM32F103xE || STM32F103xG */ /* Note: Following vector table addresses must be defined in line with linker configuration. */ /*!< Uncomment the following line if you need to relocate the vector table anywhere in Flash or Sram, else the vector table is kept at the automatic remap of boot address selected */ /* #define USER_VECT_TAB_ADDRESS */ #if defined(USER_VECT_TAB_ADDRESS) /*!< Uncomment the following line if you need to relocate your vector Table in Sram else user remap will be done in Flash. */ /* #define VECT_TAB_SRAM */ #if defined(VECT_TAB_SRAM) #define VECT_TAB_BASE_ADDRESS SRAM_BASE /*!< Vector Table base address field. This value must be a multiple of 0x200. */ #define VECT_TAB_OFFSET 0x00000000U /*!< Vector Table base offset field. This value must be a multiple of 0x200. */ #else #define VECT_TAB_BASE_ADDRESS FLASH_BASE /*!< Vector Table base address field. This value must be a multiple of 0x200. */ #define VECT_TAB_OFFSET 0x00000000U /*!< Vector Table base offset field. This value must be a multiple of 0x200. */ #endif /* VECT_TAB_SRAM */ #endif /* USER_VECT_TAB_ADDRESS */ /******************************************************************************/ /** * @} */ /** @addtogroup STM32F1xx_System_Private_Macros * @{ */ /** * @} */ /** @addtogroup STM32F1xx_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[16U] = {0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 6, 7, 8, 9}; const uint8_t APBPrescTable[8U] = {0, 0, 0, 0, 1, 2, 3, 4}; /** * @} */ /** @addtogroup STM32F1xx_System_Private_FunctionPrototypes * @{ */ #if defined(STM32F100xE) || defined(STM32F101xE) || defined(STM32F101xG) || defined(STM32F103xE) || defined(STM32F103xG) #ifdef DATA_IN_ExtSRAM static void SystemInit_ExtMemCtl(void); #endif /* DATA_IN_ExtSRAM */ #endif /* STM32F100xE || STM32F101xE || STM32F101xG || STM32F103xE || STM32F103xG */ /** * @} */ /** @addtogroup STM32F1xx_System_Private_Functions * @{ */ /** * @brief Setup the microcontroller system * Initialize the Embedded Flash Interface, the PLL and update the * SystemCoreClock variable. * @note This function should be used only after reset. * @param None * @retval None */ void SystemInit (void) { #if defined(STM32F100xE) || defined(STM32F101xE) || defined(STM32F101xG) || defined(STM32F103xE) || defined(STM32F103xG) #ifdef DATA_IN_ExtSRAM SystemInit_ExtMemCtl(); #endif /* DATA_IN_ExtSRAM */ #endif /* Configure the Vector Table location -------------------------------------*/ #if defined(USER_VECT_TAB_ADDRESS) SCB->VTOR = VECT_TAB_BASE_ADDRESS | VECT_TAB_OFFSET; /* Vector Table Relocation in Internal SRAM. */ #endif /* USER_VECT_TAB_ADDRESS */ } /** * @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: * *