keniti akiba
f303_h_p1 1
Diff: stm32g031_lpusrt1_1/system_stm32g0xx.c
- Revision:
- 13:3defea0d9a9e
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/stm32g031_lpusrt1_1/system_stm32g0xx.c Sun Nov 28 01:28:50 2021 +0000
@@ -0,0 +1,291 @@
+/**
+ ******************************************************************************
+ * @file system_stm32g0xx.c
+ * @author MCD Application Team
+ * @brief CMSIS Cortex-M0+ 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_stm32g0xx.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 (8 MHz then 16 MHz) is used as system clock source.
+ * Then SystemInit() function is called, in "startup_stm32g0xx.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
+ *-----------------------------------------------------------------------------
+ * APB Prescaler | 1
+ *-----------------------------------------------------------------------------
+ * HSI Division factor | 1
+ *-----------------------------------------------------------------------------
+ * PLL_M | 1
+ *-----------------------------------------------------------------------------
+ * PLL_N | 8
+ *-----------------------------------------------------------------------------
+ * PLL_P | 7
+ *-----------------------------------------------------------------------------
+ * PLL_Q | 2
+ *-----------------------------------------------------------------------------
+ * PLL_R | 2
+ *-----------------------------------------------------------------------------
+ * Require 48MHz for RNG | Disabled
+ *-----------------------------------------------------------------------------
+ *=============================================================================
+ ******************************************************************************
+ * @attention
+ *
+ * <h2><center>© Copyright (c) 2018 STMicroelectronics.
+ * All rights reserved.</center></h2>
+ *
+ * This software component is licensed by ST under Apache License, Version 2.0,
+ * 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/Apache-2.0
+ *
+ ******************************************************************************
+ */
+
+/** @addtogroup CMSIS
+ * @{
+ */
+
+/** @addtogroup stm32g0xx_system
+ * @{
+ */
+
+/** @addtogroup STM32G0xx_System_Private_Includes
+ * @{
+ */
+
+#include "stm32g0xx.h"
+
+#if !defined (HSE_VALUE)
+#define HSE_VALUE (8000000UL) /*!< Value of the External oscillator in Hz */
+#endif /* HSE_VALUE */
+
+#if !defined (HSI_VALUE)
+ #define HSI_VALUE (16000000UL) /*!< Value of the Internal oscillator in Hz*/
+#endif /* HSI_VALUE */
+
+#if !defined (LSI_VALUE)
+ #define LSI_VALUE (32000UL) /*!< Value of LSI in Hz*/
+#endif /* LSI_VALUE */
+
+#if !defined (LSE_VALUE)
+ #define LSE_VALUE (32768UL) /*!< Value of LSE in Hz*/
+#endif /* LSE_VALUE */
+
+/**
+ * @}
+ */
+
+/** @addtogroup STM32G0xx_System_Private_TypesDefinitions
+ * @{
+ */
+
+/**
+ * @}
+ */
+
+/** @addtogroup STM32G0xx_System_Private_Defines
+ * @{
+ */
+
+/************************* Miscellaneous Configuration ************************/
+/*!< Uncomment the following line if you need to relocate your vector Table in
+ Internal SRAM. */
+/* #define VECT_TAB_SRAM */
+#define VECT_TAB_OFFSET 0x0U /*!< Vector Table base offset field.
+ This value must be a multiple of 0x100. */
+/******************************************************************************/
+/**
+ * @}
+ */
+
+/** @addtogroup STM32G0xx_System_Private_Macros
+ * @{
+ */
+
+/**
+ * @}
+ */
+
+/** @addtogroup STM32G0xx_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 = 16000000UL;
+
+ const uint32_t AHBPrescTable[16UL] = {0UL, 0UL, 0UL, 0UL, 0UL, 0UL, 0UL, 0UL, 1UL, 2UL, 3UL, 4UL, 6UL, 7UL, 8UL, 9UL};
+ const uint32_t APBPrescTable[8UL] = {0UL, 0UL, 0UL, 0UL, 1UL, 2UL, 3UL, 4UL};
+
+/**
+ * @}
+ */
+
+/** @addtogroup STM32G0xx_System_Private_FunctionPrototypes
+ * @{
+ */
+
+/**
+ * @}
+ */
+
+/** @addtogroup STM32G0xx_System_Private_Functions
+ * @{
+ */
+
+/**
+ * @brief Setup the microcontroller system.
+ * @param None
+ * @retval None
+ */
+void SystemInit(void)
+{
+ /* 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(**) / HSI division factor
+ *
+ * - If SYSCLK source is HSE, SystemCoreClock will contain the HSE_VALUE(***)
+ *
+ * - If SYSCLK source is LSI, SystemCoreClock will contain the LSI_VALUE
+ *
+ * - If SYSCLK source is LSE, SystemCoreClock will contain the LSE_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 stm32g0xx_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 stm32g0xx_hal_conf.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;
+ uint32_t pllvco;
+ uint32_t pllr;
+ uint32_t pllsource;
+ uint32_t pllm;
+ uint32_t hsidiv;
+
+ /* Get SYSCLK source -------------------------------------------------------*/
+ switch (RCC->CFGR & RCC_CFGR_SWS)
+ {
+ case RCC_CFGR_SWS_0: /* HSE used as system clock */
+ SystemCoreClock = HSE_VALUE;
+ break;
+
+ case (RCC_CFGR_SWS_1 | RCC_CFGR_SWS_0): /* LSI used as system clock */
+ SystemCoreClock = LSI_VALUE;
+ break;
+
+ case RCC_CFGR_SWS_2: /* LSE used as system clock */
+ SystemCoreClock = LSE_VALUE;
+ break;
+
+ case RCC_CFGR_SWS_1: /* PLL used as system clock */
+ /* 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) >> RCC_PLLCFGR_PLLM_Pos) + 1UL;
+
+ if(pllsource == 0x03UL) /* HSE used as PLL clock source */
+ {
+ pllvco = (HSE_VALUE / pllm);
+ }
+ else /* HSI used as PLL clock source */
+ {
+ pllvco = (HSI_VALUE / pllm);
+ }
+ pllvco = pllvco * ((RCC->PLLCFGR & RCC_PLLCFGR_PLLN) >> RCC_PLLCFGR_PLLN_Pos);
+ pllr = (((RCC->PLLCFGR & RCC_PLLCFGR_PLLR) >> RCC_PLLCFGR_PLLR_Pos) + 1UL);
+
+ SystemCoreClock = pllvco/pllr;
+ break;
+
+ case 0x00000000U: /* HSI used as system clock */
+ default: /* HSI used as system clock */
+ hsidiv = (1UL << ((READ_BIT(RCC->CR, RCC_CR_HSIDIV))>> RCC_CR_HSIDIV_Pos));
+ SystemCoreClock = (HSI_VALUE/hsidiv);
+ break;
+ }
+ /* Compute HCLK clock frequency --------------------------------------------*/
+ /* Get HCLK prescaler */
+ tmp = AHBPrescTable[((RCC->CFGR & RCC_CFGR_HPRE) >> RCC_CFGR_HPRE_Pos)];
+ /* HCLK clock frequency */
+ SystemCoreClock >>= tmp;
+}
+
+
+/**
+ * @}
+ */
+
+/**
+ * @}
+ */
+
+/**
+ * @}
+ */
+
+/************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/
+