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Diffstat (limited to 'Core/Src/system_stm32l0xx.c')
| -rw-r--r-- | Core/Src/system_stm32l0xx.c | 275 |
1 files changed, 275 insertions, 0 deletions
diff --git a/Core/Src/system_stm32l0xx.c b/Core/Src/system_stm32l0xx.c new file mode 100644 index 0000000..9189ed8 --- /dev/null +++ b/Core/Src/system_stm32l0xx.c @@ -0,0 +1,275 @@ +/**
+ ******************************************************************************
+ * @file system_stm32l0xx.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_stm32l0xx.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
+ *
+ * <h2><center>© Copyright(c) 2016 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 stm32l0xx_system
+ * @{
+ */
+
+/** @addtogroup STM32L0xx_System_Private_Includes
+ * @{
+ */
+
+#include "stm32l0xx.h"
+
+#if !defined (HSE_VALUE)
+ #define HSE_VALUE ((uint32_t)8000000U) /*!< Value of the External oscillator in Hz */
+#endif /* HSE_VALUE */
+
+#if !defined (MSI_VALUE)
+ #define MSI_VALUE ((uint32_t)2097152U) /*!< Value of the Internal oscillator in Hz*/
+#endif /* MSI_VALUE */
+
+#if !defined (HSI_VALUE)
+ #define HSI_VALUE ((uint32_t)16000000U) /*!< Value of the Internal oscillator in Hz*/
+#endif /* HSI_VALUE */
+
+
+/**
+ * @}
+ */
+
+/** @addtogroup STM32L0xx_System_Private_TypesDefinitions
+ * @{
+ */
+
+/**
+ * @}
+ */
+
+/** @addtogroup STM32L0xx_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 STM32L0xx_System_Private_Macros
+ * @{
+ */
+
+/**
+ * @}
+ */
+
+/** @addtogroup STM32L0xx_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 = 2097152U; /* 32.768 kHz * 2^6 */
+ 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 uint8_t PLLMulTable[9] = {3U, 4U, 6U, 8U, 12U, 16U, 24U, 32U, 48U};
+
+/**
+ * @}
+ */
+
+/** @addtogroup STM32L0xx_System_Private_FunctionPrototypes
+ * @{
+ */
+
+/**
+ * @}
+ */
+
+/** @addtogroup STM32L0xx_System_Private_Functions
+ * @{
+ */
+
+/**
+ * @brief Setup the microcontroller system.
+ * @param None
+ * @retval None
+ */
+void SystemInit (void)
+{
+ /* 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 MSI, SystemCoreClock will contain the MSI
+ * value as defined by the MSI range.
+ *
+ * - 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 stm32l0xx_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 stm32l0xx_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 = 0U, pllmul = 0U, plldiv = 0U, pllsource = 0U, msirange = 0U;
+
+ /* Get SYSCLK source -------------------------------------------------------*/
+ tmp = RCC->CFGR & RCC_CFGR_SWS;
+
+ switch (tmp)
+ {
+ case 0x00U: /* MSI used as system clock */
+ msirange = (RCC->ICSCR & RCC_ICSCR_MSIRANGE) >> RCC_ICSCR_MSIRANGE_Pos;
+ SystemCoreClock = (32768U * (1U << (msirange + 1U)));
+ break;
+ case 0x04U: /* HSI used as system clock */
+ if ((RCC->CR & RCC_CR_HSIDIVF) != 0U)
+ {
+ SystemCoreClock = HSI_VALUE / 4U;
+ }
+ else
+ {
+ SystemCoreClock = HSI_VALUE;
+ }
+ break;
+ case 0x08U: /* HSE used as system clock */
+ SystemCoreClock = HSE_VALUE;
+ break;
+ default: /* PLL used as system clock */
+ /* Get PLL clock source and multiplication factor ----------------------*/
+ pllmul = RCC->CFGR & RCC_CFGR_PLLMUL;
+ plldiv = RCC->CFGR & RCC_CFGR_PLLDIV;
+ pllmul = PLLMulTable[(pllmul >> RCC_CFGR_PLLMUL_Pos)];
+ plldiv = (plldiv >> RCC_CFGR_PLLDIV_Pos) + 1U;
+
+ pllsource = RCC->CFGR & RCC_CFGR_PLLSRC;
+
+ if (pllsource == 0x00U)
+ {
+ /* HSI oscillator clock selected as PLL clock entry */
+ if ((RCC->CR & RCC_CR_HSIDIVF) != 0U)
+ {
+ SystemCoreClock = (((HSI_VALUE / 4U) * pllmul) / plldiv);
+ }
+ else
+ {
+ SystemCoreClock = (((HSI_VALUE) * pllmul) / plldiv);
+ }
+ }
+ else
+ {
+ /* HSE selected as PLL clock entry */
+ SystemCoreClock = (((HSE_VALUE) * pllmul) / plldiv);
+ }
+ 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****/
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