/** | |
****************************************************************************** | |
* @file system_stm32f3xx.c | |
* @author MCD Application Team | |
* @brief CMSIS Cortex-M4 Device Peripheral Access Layer System Source File. | |
* | |
* 1. 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_stm32f3xx.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_stm32f3xx.s" file, to | |
* configure the system clock before to branch to main program. | |
* | |
* 3. This file configures the system clock as follows: | |
*============================================================================= | |
* Supported STM32F3xx device | |
*----------------------------------------------------------------------------- | |
* System Clock source | HSI | |
*----------------------------------------------------------------------------- | |
* SYSCLK(Hz) | 8000000 | |
*----------------------------------------------------------------------------- | |
* HCLK(Hz) | 8000000 | |
*----------------------------------------------------------------------------- | |
* AHB Prescaler | 1 | |
*----------------------------------------------------------------------------- | |
* APB2 Prescaler | 1 | |
*----------------------------------------------------------------------------- | |
* APB1 Prescaler | 1 | |
*----------------------------------------------------------------------------- | |
* USB Clock | DISABLE | |
*----------------------------------------------------------------------------- | |
*============================================================================= | |
****************************************************************************** | |
* @attention | |
* | |
* <h2><center>© COPYRIGHT(c) 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 stm32f3xx_system | |
* @{ | |
*/ | |
/** @addtogroup STM32F3xx_System_Private_Includes | |
* @{ | |
*/ | |
#include "stm32f3xx.h" | |
/** | |
* @} | |
*/ | |
/** @addtogroup STM32F3xx_System_Private_TypesDefinitions | |
* @{ | |
*/ | |
/** | |
* @} | |
*/ | |
/** @addtogroup STM32F3xx_System_Private_Defines | |
* @{ | |
*/ | |
#if !defined (HSE_VALUE) | |
#define HSE_VALUE ((uint32_t)8000000) /*!< 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 ((uint32_t)8000000) /*!< 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 relocate your vector Table in | |
Internal SRAM. */ | |
/* #define VECT_TAB_SRAM */ | |
#define VECT_TAB_OFFSET 0x0 /*!< Vector Table base offset field. | |
This value must be a multiple of 0x200. */ | |
/** | |
* @} | |
*/ | |
/** @addtogroup STM32F3xx_System_Private_Macros | |
* @{ | |
*/ | |
/** | |
* @} | |
*/ | |
/** @addtogroup STM32F3xx_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 there is no need to | |
call the 2 first functions listed above, since SystemCoreClock variable is | |
updated automatically. | |
*/ | |
uint32_t SystemCoreClock = 8000000; | |
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 STM32F3xx_System_Private_FunctionPrototypes | |
* @{ | |
*/ | |
/** | |
* @} | |
*/ | |
/** @addtogroup STM32F3xx_System_Private_Functions | |
* @{ | |
*/ | |
/** | |
* @brief Setup the microcontroller system | |
* Initialize the FPU setting, vector table location and the PLL configuration is reset. | |
* @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 |= 0x00000001U; | |
/* Reset CFGR register */ | |
RCC->CFGR &= 0xF87FC00CU; | |
/* Reset HSEON, CSSON and PLLON bits */ | |
RCC->CR &= 0xFEF6FFFFU; | |
/* Reset HSEBYP bit */ | |
RCC->CR &= 0xFFFBFFFFU; | |
/* Reset PLLSRC, PLLXTPRE, PLLMUL and USBPRE bits */ | |
RCC->CFGR &= 0xFF80FFFFU; | |
/* Reset PREDIV1[3:0] bits */ | |
RCC->CFGR2 &= 0xFFFFFFF0U; | |
/* Reset USARTSW[1:0], I2CSW and TIMs bits */ | |
RCC->CFGR3 &= 0xFF00FCCCU; | |
/* Disable all interrupts */ | |
RCC->CIR = 0x00000000U; | |
#ifdef VECT_TAB_SRAM | |
SCB->VTOR = SRAM_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 stm32f3xx_hal.h file (default value | |
* 8 MHz) but the real value may vary depending on the variations | |
* in voltage and temperature. | |
* | |
* (**) HSE_VALUE is a constant defined in stm32f3xx_hal.h file (default value | |
* 8 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, pllmull = 0, pllsource = 0, predivfactor = 0; | |
/* Get SYSCLK source -------------------------------------------------------*/ | |
tmp = RCC->CFGR & RCC_CFGR_SWS; | |
switch (tmp) | |
{ | |
case RCC_CFGR_SWS_HSI: /* HSI used as system clock */ | |
SystemCoreClock = HSI_VALUE; | |
break; | |
case RCC_CFGR_SWS_HSE: /* HSE used as system clock */ | |
SystemCoreClock = HSE_VALUE; | |
break; | |
case RCC_CFGR_SWS_PLL: /* PLL used as system clock */ | |
/* Get PLL clock source and multiplication factor ----------------------*/ | |
pllmull = RCC->CFGR & RCC_CFGR_PLLMUL; | |
pllsource = RCC->CFGR & RCC_CFGR_PLLSRC; | |
pllmull = ( pllmull >> 18) + 2; | |
#if defined (STM32F302xE) || defined (STM32F303xE) || defined (STM32F398xx) | |
predivfactor = (RCC->CFGR2 & RCC_CFGR2_PREDIV) + 1; | |
if (pllsource == RCC_CFGR_PLLSRC_HSE_PREDIV) | |
{ | |
/* HSE oscillator clock selected as PREDIV1 clock entry */ | |
SystemCoreClock = (HSE_VALUE / predivfactor) * pllmull; | |
} | |
else | |
{ | |
/* HSI oscillator clock selected as PREDIV1 clock entry */ | |
SystemCoreClock = (HSI_VALUE / predivfactor) * pllmull; | |
} | |
#else | |
if (pllsource == RCC_CFGR_PLLSRC_HSI_DIV2) | |
{ | |
/* HSI oscillator clock divided by 2 selected as PLL clock entry */ | |
SystemCoreClock = (HSI_VALUE >> 1) * pllmull; | |
} | |
else | |
{ | |
predivfactor = (RCC->CFGR2 & RCC_CFGR2_PREDIV) + 1; | |
/* HSE oscillator clock selected as PREDIV1 clock entry */ | |
SystemCoreClock = (HSE_VALUE / predivfactor) * pllmull; | |
} | |
#endif /* STM32F302xE || STM32F303xE || STM32F398xx */ | |
break; | |
default: /* HSI used as system clock */ | |
SystemCoreClock = HSI_VALUE; | |
break; | |
} | |
/* Compute HCLK clock frequency ----------------*/ | |
/* Get HCLK prescaler */ | |
tmp = AHBPrescTable[((RCC->CFGR & RCC_CFGR_HPRE) >> 4)]; | |
/* HCLK clock frequency */ | |
SystemCoreClock >>= tmp; | |
} | |
/** | |
* @} | |
*/ | |
/** | |
* @} | |
*/ | |
/** | |
* @} | |
*/ | |
/************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/ | |