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Diffstat (limited to 'lib/stm32g4/system_stm32g4xx.c')
| -rw-r--r-- | lib/stm32g4/system_stm32g4xx.c | 287 |
1 files changed, 287 insertions, 0 deletions
diff --git a/lib/stm32g4/system_stm32g4xx.c b/lib/stm32g4/system_stm32g4xx.c new file mode 100644 index 00000000..92fc662a --- /dev/null +++ b/lib/stm32g4/system_stm32g4xx.c @@ -0,0 +1,287 @@ +/** + ****************************************************************************** + * @file system_stm32g4xx.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_stm32g4xx.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. + * + * After each device reset the HSI (16 MHz) is used as system clock source. + * Then SystemInit() function is called, in "startup_stm32g4xx.s" file, to + * configure the system clock before to branch to main program. + * + * This file configures the system clock as follows: + *============================================================================= + *----------------------------------------------------------------------------- + * System Clock source | HSI + *----------------------------------------------------------------------------- + * SYSCLK(Hz) | 16000000 + *----------------------------------------------------------------------------- + * HCLK(Hz) | 16000000 + *----------------------------------------------------------------------------- + * AHB Prescaler | 1 + *----------------------------------------------------------------------------- + * APB1 Prescaler | 1 + *----------------------------------------------------------------------------- + * APB2 Prescaler | 1 + *----------------------------------------------------------------------------- + * PLL_M | 1 + *----------------------------------------------------------------------------- + * PLL_N | 16 + *----------------------------------------------------------------------------- + * PLL_P | 7 + *----------------------------------------------------------------------------- + * PLL_Q | 2 + *----------------------------------------------------------------------------- + * PLL_R | 2 + *----------------------------------------------------------------------------- + * Require 48MHz for RNG | Disabled + *----------------------------------------------------------------------------- + *============================================================================= + ****************************************************************************** + * @attention + * + * <h2><center>© Copyright (c) 2019 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 stm32g4xx_system + * @{ + */ + +/** @addtogroup STM32G4xx_System_Private_Includes + * @{ + */ + +#include "stm32g4xx.h" + +#if !defined (HSE_VALUE) + #define HSE_VALUE 24000000U /*!< Value of the External oscillator in Hz */ +#endif /* HSE_VALUE */ + +#if !defined (HSI_VALUE) + #define HSI_VALUE 16000000U /*!< Value of the Internal oscillator in Hz*/ +#endif /* HSI_VALUE */ + +/** + * @} + */ + +/** @addtogroup STM32G4xx_System_Private_TypesDefinitions + * @{ + */ + +/** + * @} + */ + +/** @addtogroup STM32G4xx_System_Private_Defines + * @{ + */ + +/************************* Miscellaneous Configuration ************************/ +/* 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 STM32G4xx_System_Private_Macros + * @{ + */ + +/** + * @} + */ + +/** @addtogroup STM32G4xx_System_Private_Variables + * @{ + */ + /* The SystemCoreClock 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 = HSI_VALUE; + + const uint8_t AHBPrescTable[16] = {0U, 0U, 0U, 0U, 0U, 0U, 0U, 0U, 1U, 2U, 3U, 4U, 6U, 7U, 8U, 9U}; + const uint8_t APBPrescTable[8] = {0U, 0U, 0U, 0U, 1U, 2U, 3U, 4U}; + +/** + * @} + */ + +/** @addtogroup STM32G4xx_System_Private_FunctionPrototypes + * @{ + */ + +/** + * @} + */ + +/** @addtogroup STM32G4xx_System_Private_Functions + * @{ + */ + +/** + * @brief Setup the microcontroller system. + * @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 + + /* Configure the Vector Table location add offset address ------------------*/ +#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: + * + * - 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 stm32g4xx_hal.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 stm32g4xx_hal.h file (default value + * 24 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, pllvco, pllr, pllsource, pllm; + + /* Get SYSCLK source -------------------------------------------------------*/ + switch (RCC->CFGR & RCC_CFGR_SWS) + { + case 0x04: /* HSI used as system clock source */ + SystemCoreClock = HSI_VALUE; + break; + + case 0x08: /* HSE used as system clock source */ + SystemCoreClock = HSE_VALUE; + break; + + case 0x0C: /* PLL used as system clock source */ + /* PLL_VCO = (HSE_VALUE or HSI_VALUE / PLLM) * PLLN + SYSCLK = PLL_VCO / PLLR + */ + pllsource = (RCC->PLLCFGR & RCC_PLLCFGR_PLLSRC); + pllm = ((RCC->PLLCFGR & RCC_PLLCFGR_PLLM) >> 4) + 1U ; + if (pllsource == 0x02UL) /* HSI used as PLL clock source */ + { + pllvco = (HSI_VALUE / pllm); + } + else /* HSE used as PLL clock source */ + { + pllvco = (HSE_VALUE / pllm); + } + pllvco = pllvco * ((RCC->PLLCFGR & RCC_PLLCFGR_PLLN) >> 8); + pllr = (((RCC->PLLCFGR & RCC_PLLCFGR_PLLR) >> 25) + 1U) * 2U; + SystemCoreClock = pllvco/pllr; + break; + + default: + 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****/ + |