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Outline
#include "stm32f4xx.h"
#define HSE_VALUE
#define HSI_VALUE
Miscellaneous Configuration
SystemCoreClock
AHBPrescTable
APBPrescTable
SystemInit()
SystemCoreClockUpdate()
Files
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CodeScopeSTM32 Libraries and SamplesTouchGFXCore/Src/system_stm32f4xx.c
 
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/** ****************************************************************************** * @file system_stm32f4xx.c * @author MCD Application Team * @brief CMSIS Cortex-M4 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_stm32f4xx.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 * * Copyright (c) 2017 STMicroelectronics. * All rights reserved. * * This software is licensed under terms that can be found in the LICENSE file * in the root directory of this software component. * If no LICENSE file comes with this software, it is provided AS-IS. * ****************************************************************************** *//* ... */ /** @addtogroup CMSIS * @{ *//* ... */ /** @addtogroup stm32f4xx_system * @{ *//* ... */ /** @addtogroup STM32F4xx_System_Private_Includes * @{ *//* ... */ #include "stm32f4xx.h" #if !defined (HSE_VALUE) #define HSE_VALUE ((uint32_t)8000000) /*!< 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 STM32F4xx_System_Private_TypesDefinitions * @{ *//* ... */ /** * @} *//* ... */ /** @addtogroup STM32F4xx_System_Private_Defines * @{ *//* ... */ /************************* Miscellaneous Configuration ************************/ /*!< Uncomment the following line if you need to use external SDRAM mounted on DK as data memory *//* ... */ /* #define DATA_IN_ExtSDRAM */ /*!< 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. *//* ... */ Miscellaneous Configuration /******************************************************************************/ /** * @} *//* ... */ /** @addtogroup STM32F4xx_System_Private_Macros * @{ *//* ... */ /** * @} *//* ... */ /** @addtogroup STM32F4xx_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 STM32F4xx_System_Private_FunctionPrototypes * @{ *//* ... */ #if defined (DATA_IN_ExtSDRAM) static void SystemInit_ExtMemCtl(void); #endif /* DATA_IN_ExtSDRAM */ /** @addtogroup STM32F4xx_System_Private_FunctionPrototypes * @{ *//* ... */ /** * @} *//* ... */ /** @addtogroup STM32F4xx_System_Private_Functions * @{ *//* ... */ /** * @brief Setup the microcontroller system * Initialize the FPU setting, vector table location and External memory * configuration. * @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 */ #endifFPU settings /* 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; #if defined (DATA_IN_ExtSDRAM) SystemInit_ExtMemCtl(); #endif /* DATA_IN_ExtSDRAM */ Reset the RCC clock configuration to the default reset state /* Configure the Vector Table location add offset address ------------------*/ #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 stm32f4xx_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 stm32f4xx_hal_conf.h file (its value * depends on the application requirements), 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 0x00: case 0x04: /* HSE used as system clock source */ SystemCoreClock = HSE_VALUE; break;case 0x04: 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); }if (pllsource != 0) { ... } else { /* HSI used as PLL clock source */ pllvco = (HSI_VALUE / pllm) * ((RCC->PLLCFGR & RCC_PLLCFGR_PLLN) >> 6); }else { ... } pllp = (((RCC->PLLCFGR & RCC_PLLCFGR_PLLP) >>16) + 1 ) *2; SystemCoreClock = pllvco/pllp; break;case 0x08: default: SystemCoreClock = HSI_VALUE; break;default }switch (tmp) { ... } Get SYSCLK source /* Compute HCLK frequency --------------------------------------------------*/ /* Get HCLK prescaler */ tmp = AHBPrescTable[((RCC->CFGR & RCC_CFGR_HPRE) >> 4)]; /* HCLK frequency */ SystemCoreClock >>= tmp; }{ ... } #if defined (DATA_IN_ExtSDRAM) /** * @brief Setup the external memory controller. * Called in startup_stm32f4xx.s before jump to main. * This function configures the external memories (SDRAM) * This SDRAM will be used as program data memory (including heap and stack). * @param None * @retval None *//* ... */ void SystemInit_ExtMemCtl(void) { register uint32_t tmpreg = 0, timeout = 0xFFFF; register __IO uint32_t index; /* Enable GPIOB, GPIOC, GPIOD, GPIOE, GPIOF and GPIOG interface clock *//* ... */ RCC->AHB1ENR |= 0x0000007E; /* Connect PBx pins to FMC Alternate function */ GPIOB->AFR[0] = 0x0CC00000; GPIOB->AFR[1] = 0x00000000; /* Configure PBx pins in Alternate function mode */ GPIOB->MODER = 0x00002A80; /* Configure PBx pins speed to 100 MHz */ GPIOB->OSPEEDR = 0x00003CC0; /* Configure PBx pins Output type to push-pull */ GPIOB->OTYPER = 0x00000000; /* No pull-up, pull-down for PBx pins */ GPIOB->PUPDR = 0x00000100; /* Connect PCx pins to FMC Alternate function */ GPIOC->AFR[0] = 0x0000000C; GPIOC->AFR[1] = 0x00000000; /* Configure PCx pins in Alternate function mode */ GPIOC->MODER = 0x00000002; /* Configure PCx pins speed to 100 MHz */ GPIOC->OSPEEDR = 0x00000003; /* Configure PCx pins Output type to push-pull */ GPIOC->OTYPER = 0x00000000; /* No pull-up, pull-down for PCx pins */ GPIOC->PUPDR = 0x00000000; /* Connect PDx pins to FMC Alternate function */ GPIOD->AFR[0] = 0x000000CC; GPIOD->AFR[1] = 0xCC000CCC; /* Configure PDx pins in Alternate function mode */ GPIOD->MODER = 0xA02A000A; /* Configure PDx pins speed to 100 MHz */ GPIOD->OSPEEDR = 0xF03F000F; /* Configure PDx pins Output type to push-pull */ GPIOD->OTYPER = 0x00000000; /* No pull-up, pull-down for PDx pins */ GPIOD->PUPDR = 0x00000000; /* Connect PEx pins to FMC Alternate function */ GPIOE->AFR[0] = 0xC00000CC; GPIOE->AFR[1] = 0xCCCCCCCC; /* Configure PEx pins in Alternate function mode */ GPIOE->MODER = 0xAAAA800A; /* Configure PEx pins speed to 100 MHz */ GPIOE->OSPEEDR = 0xFFFFC00F; /* Configure PEx pins Output type to push-pull */ GPIOE->OTYPER = 0x00000000; /* No pull-up, pull-down for PEx pins */ GPIOE->PUPDR = 0x00000000; /* Connect PFx pins to FMC Alternate function */ GPIOF->AFR[0] = 0x00CCCCCC; GPIOF->AFR[1] = 0xCCCCC000; /* Configure PFx pins in Alternate function mode */ GPIOF->MODER = 0xAA800AAA; /* Configure PFx pins speed to 100 MHz */ GPIOF->OSPEEDR = 0xFFC00FFF; /* Configure PFx pins Output type to push-pull */ GPIOF->OTYPER = 0x00000000; /* No pull-up, pull-down for PFx pins */ GPIOF->PUPDR = 0x00000000; /* Connect PGx pins to FMC Alternate function */ GPIOG->AFR[0] = 0x00CC00CC; GPIOG->AFR[1] = 0xC000000C; /* Configure PGx pins in Alternate function mode */ GPIOG->MODER = 0x80020A0A; /* Configure PGx pins speed to 100 MHz */ GPIOG->OSPEEDR = 0xC0030F0F; /* Configure PGx pins Output type to push-pull */ GPIOG->OTYPER = 0x00000000; /* No pull-up, pull-down for PGx pins */ GPIOG->PUPDR = 0x00000000; /* FMC Configuration */ /* Enable the FMC interface clock */ RCC->AHB3ENR |= 0x00000001; /* Configure and enable SDRAM bank2 */ FMC_Bank5_6->SDCR[0] = 0x00002ED0; FMC_Bank5_6->SDCR[1] = 0x000001D4; FMC_Bank5_6->SDTR[0] = 0x0F1F6FFF; FMC_Bank5_6->SDTR[1] = 0x01010361; /* SDRAM initialization sequence */ /* Clock enable command */ FMC_Bank5_6->SDCMR = 0x00000009; tmpreg = FMC_Bank5_6->SDSR & 0x00000020; while((tmpreg != 0) && (timeout-- > 0)) { tmpreg = FMC_Bank5_6->SDSR & 0x00000020; }while ((tmpreg != 0) && (timeout-- > 0)) { ... } /* Delay */ for (index = 0; index<1000; index++); /* PALL command */ FMC_Bank5_6->SDCMR = 0x0000000A; tmpreg = FMC_Bank5_6->SDSR & 0x00000020; timeout = 0xFFFF; while((tmpreg != 0) && (timeout-- > 0)) { tmpreg = FMC_Bank5_6->SDSR & 0x00000020; }while ((tmpreg != 0) && (timeout-- > 0)) { ... } /* Auto refresh command */ FMC_Bank5_6->SDCMR = 0x0000006B; tmpreg = FMC_Bank5_6->SDSR & 0x00000020; timeout = 0xFFFF; while((tmpreg != 0) && (timeout-- > 0)) { tmpreg = FMC_Bank5_6->SDSR & 0x00000020; }while ((tmpreg != 0) && (timeout-- > 0)) { ... } /* MRD register program */ FMC_Bank5_6->SDCMR = 0x0004620C; tmpreg = FMC_Bank5_6->SDSR & 0x00000020; timeout = 0xFFFF; while((tmpreg != 0) && (timeout-- > 0)) { tmpreg = FMC_Bank5_6->SDSR & 0x00000020; }while ((tmpreg != 0) && (timeout-- > 0)) { ... } /* Set refresh count */ tmpreg = FMC_Bank5_6->SDRTR; FMC_Bank5_6->SDRTR = (tmpreg | (0x0000056A<<1)); /* Disable write protection */ tmpreg = FMC_Bank5_6->SDCR[1]; FMC_Bank5_6->SDCR[1] = (tmpreg & 0xFFFFFDFF); }SystemInit_ExtMemCtl (void) { ... } /* ... */#endif /* DATA_IN_ExtSDRAM */ /** * @} *//* ... */ /** * @} *//* ... */ /** * @} *//* ... */