/** ****************************************************************************** * @file system_stm32u5xx_ns.c * @author MCD Application Team * @brief CMSIS Cortex-M33 Device Peripheral Access Layer System Source File * to be used in non-secure application when the system implements * the TrustZone-M security. * * This file provides two functions and one global variable to be called from * user application: * - SystemInit(): This function is called at non-secure startup before * branch to non-secure main program. * This call is made inside the "startup_stm32u5xx.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 MSI (4 MHz) is used as system clock source. * Then SystemInit() function is called, in "startup_stm32u5xx.s" file, to * configure the system clock before to branch to main secure program. * Later, when non-secure SystemInit() function is called, in "startup_stm32u5xx.s" * file, the system clock may have been updated from reset value by the main * secure program. * ****************************************************************************** * @attention * * Copyright (c) 2021 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 STM32U5xx_system * @{ */ /** @addtogroup STM32U5xx_System_Private_Includes * @{ */ #include "stm32u5xx.h" /** * @} */ /** @addtogroup STM32U5xx_System_Private_TypesDefinitions * @{ */ /** * @} */ /** @addtogroup STM32U5xx_System_Private_Defines * @{ */ #if !defined (HSE_VALUE) #define HSE_VALUE 16000000U /*!< Value of the External oscillator in Hz */ #endif /* HSE_VALUE */ #if !defined (MSI_VALUE) #define MSI_VALUE 4000000U /*!< Value of the Internal oscillator in Hz*/ #endif /* MSI_VALUE */ #if !defined (HSI_VALUE) #define HSI_VALUE 16000000U /*!< Value of the Internal oscillator in Hz*/ #endif /* HSI_VALUE */ /** * @} */ /** @addtogroup STM32U5xx_System_Private_Macros * @{ */ /** * @} */ /** @addtogroup STM32U5xx_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 = 4000000U; 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}; const uint32_t MSIRangeTable[16] = {48000000U,24000000U,16000000U,12000000U, 4000000U, 2000000U, 1500000U,\ 1000000U, 3072000U, 1536000U,1024000U, 768000U, 400000U, 200000U, 150000U, 100000U}; /** * @} */ /** @addtogroup STM32U5xx_System_Private_FunctionPrototypes * @{ */ /** * @} */ /** @addtogroup STM32U5xx_System_Private_Functions * @{ */ /** * @brief Setup the microcontroller system. * @retval None */ void SystemInit(void) { /* Nothing done in non-secure */ /* Non-secure main application shall call SystemCoreClockUpdate() to update */ /* the SystemCoreClock variable to insure non-secure application relies on */ /* the initial clock reference set by secure application. */ } /** * @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 From the non-secure application, the SystemCoreClock value is * retrieved from the secure domain via a Non-Secure Callable function * since the RCC peripheral may be protected with security attributes * that prevent to compute the SystemCoreClock variable from the RCC * peripheral registers. * * @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 MSI, SystemCoreClock will contain the MSI_VALUE(*) * * - 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(*) or MSI_VALUE(*) multiplied/divided by the PLL factors. * * (*) MSI_VALUE is a constant defined in stm32u5xx_hal.h file (default value * 4 MHz) but the real value may vary depending on the variations * in voltage and temperature. * * (**) HSI_VALUE is a constant defined in stm32u5xx_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 stm32u5xx_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. * * @retval None */ void SystemCoreClockUpdate(void) { /* Get the SystemCoreClock value from the secure domain */ SystemCoreClock = SECURE_SystemCoreClockUpdate(); } /** * @} */ /** * @} */ /** * @} */