354 lines
13 KiB
C
354 lines
13 KiB
C
/**
|
|
******************************************************************************
|
|
* @file system_stm32l4xx.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_stm32l4xx.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_stm32l4xx.s" file, to
|
|
* configure the system clock before to branch to main program.
|
|
*
|
|
* This file configures the system clock as follows:
|
|
*=============================================================================
|
|
*-----------------------------------------------------------------------------
|
|
* System Clock source | MSI
|
|
*-----------------------------------------------------------------------------
|
|
* SYSCLK(Hz) | 4000000
|
|
*-----------------------------------------------------------------------------
|
|
* HCLK(Hz) | 4000000
|
|
*-----------------------------------------------------------------------------
|
|
* AHB Prescaler | 1
|
|
*-----------------------------------------------------------------------------
|
|
* APB1 Prescaler | 1
|
|
*-----------------------------------------------------------------------------
|
|
* APB2 Prescaler | 1
|
|
*-----------------------------------------------------------------------------
|
|
* PLL_M | 1
|
|
*-----------------------------------------------------------------------------
|
|
* PLL_N | 8
|
|
*-----------------------------------------------------------------------------
|
|
* PLL_P | 7
|
|
*-----------------------------------------------------------------------------
|
|
* PLL_Q | 2
|
|
*-----------------------------------------------------------------------------
|
|
* PLL_R | 2
|
|
*-----------------------------------------------------------------------------
|
|
* PLLSAI1_P | NA
|
|
*-----------------------------------------------------------------------------
|
|
* PLLSAI1_Q | NA
|
|
*-----------------------------------------------------------------------------
|
|
* PLLSAI1_R | NA
|
|
*-----------------------------------------------------------------------------
|
|
* PLLSAI2_P | NA
|
|
*-----------------------------------------------------------------------------
|
|
* PLLSAI2_Q | NA
|
|
*-----------------------------------------------------------------------------
|
|
* PLLSAI2_R | NA
|
|
*-----------------------------------------------------------------------------
|
|
* Require 48MHz for USB OTG FS, | Disabled
|
|
* SDIO and RNG clock |
|
|
*-----------------------------------------------------------------------------
|
|
*=============================================================================
|
|
******************************************************************************
|
|
* @attention
|
|
*
|
|
* <h2><center>© COPYRIGHT(c) 2017 STMicroelectronics</center></h2>
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without modification,
|
|
* are permitted provided that the following conditions are met:
|
|
* 1. Redistributions of source code must retain the above copyright notice,
|
|
* this list of conditions and the following disclaimer.
|
|
* 2. Redistributions in binary form must reproduce the above copyright notice,
|
|
* this list of conditions and the following disclaimer in the documentation
|
|
* and/or other materials provided with the distribution.
|
|
* 3. Neither the name of STMicroelectronics nor the names of its contributors
|
|
* may be used to endorse or promote products derived from this software
|
|
* without specific prior written permission.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
|
|
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
|
|
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
|
|
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
|
|
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
|
|
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
|
|
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
|
|
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
|
*
|
|
******************************************************************************
|
|
*/
|
|
|
|
/** @addtogroup CMSIS
|
|
* @{
|
|
*/
|
|
|
|
/** @addtogroup stm32l4xx_system
|
|
* @{
|
|
*/
|
|
|
|
/** @addtogroup STM32L4xx_System_Private_Includes
|
|
* @{
|
|
*/
|
|
|
|
#include "stm32l4xx.h"
|
|
|
|
#if !defined (HSE_VALUE)
|
|
#define HSE_VALUE 8000000U /*!< 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 STM32L4xx_System_Private_TypesDefinitions
|
|
* @{
|
|
*/
|
|
|
|
/**
|
|
* @}
|
|
*/
|
|
|
|
/** @addtogroup STM32L4xx_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 0x00 /*!< Vector Table base offset field.
|
|
This value must be a multiple of 0x200. */
|
|
/******************************************************************************/
|
|
/**
|
|
* @}
|
|
*/
|
|
|
|
/** @addtogroup STM32L4xx_System_Private_Macros
|
|
* @{
|
|
*/
|
|
|
|
/**
|
|
* @}
|
|
*/
|
|
|
|
/** @addtogroup STM32L4xx_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[12] = {100000U, 200000U, 400000U, 800000U, 1000000U, 2000000U, \
|
|
4000000U, 8000000U, 16000000U, 24000000U, 32000000U, 48000000U};
|
|
/**
|
|
* @}
|
|
*/
|
|
|
|
/** @addtogroup STM32L4xx_System_Private_FunctionPrototypes
|
|
* @{
|
|
*/
|
|
|
|
/**
|
|
* @}
|
|
*/
|
|
|
|
/** @addtogroup STM32L4xx_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
|
|
|
|
/* Reset the RCC clock configuration to the default reset state ------------*/
|
|
/* Set MSION bit */
|
|
RCC->CR |= RCC_CR_MSION;
|
|
|
|
/* Reset CFGR register */
|
|
RCC->CFGR = 0x00000000U;
|
|
|
|
/* Reset HSEON, CSSON , HSION, and PLLON bits */
|
|
RCC->CR &= 0xEAF6FFFFU;
|
|
|
|
/* Reset PLLCFGR register */
|
|
RCC->PLLCFGR = 0x00001000U;
|
|
|
|
/* Reset HSEBYP bit */
|
|
RCC->CR &= 0xFFFBFFFFU;
|
|
|
|
/* Disable all interrupts */
|
|
RCC->CIER = 0x00000000U;
|
|
|
|
/* 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 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 stm32l4xx_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 stm32l4xx_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 stm32l4xx_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, msirange = 0U, pllvco = 0U, pllr = 2U, pllsource = 0U, pllm = 2U;
|
|
|
|
/* Get MSI Range frequency--------------------------------------------------*/
|
|
if((RCC->CR & RCC_CR_MSIRGSEL) == RESET)
|
|
{ /* MSISRANGE from RCC_CSR applies */
|
|
msirange = (RCC->CSR & RCC_CSR_MSISRANGE) >> 8U;
|
|
}
|
|
else
|
|
{ /* MSIRANGE from RCC_CR applies */
|
|
msirange = (RCC->CR & RCC_CR_MSIRANGE) >> 4U;
|
|
}
|
|
/*MSI frequency range in HZ*/
|
|
msirange = MSIRangeTable[msirange];
|
|
|
|
/* Get SYSCLK source -------------------------------------------------------*/
|
|
switch (RCC->CFGR & RCC_CFGR_SWS)
|
|
{
|
|
case 0x00: /* MSI used as system clock source */
|
|
SystemCoreClock = msirange;
|
|
break;
|
|
|
|
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 or MSI_VALUE/ PLLM) * PLLN
|
|
SYSCLK = PLL_VCO / PLLR
|
|
*/
|
|
pllsource = (RCC->PLLCFGR & RCC_PLLCFGR_PLLSRC);
|
|
pllm = ((RCC->PLLCFGR & RCC_PLLCFGR_PLLM) >> 4U) + 1U ;
|
|
|
|
switch (pllsource)
|
|
{
|
|
case 0x02: /* HSI used as PLL clock source */
|
|
pllvco = (HSI_VALUE / pllm);
|
|
break;
|
|
|
|
case 0x03: /* HSE used as PLL clock source */
|
|
pllvco = (HSE_VALUE / pllm);
|
|
break;
|
|
|
|
default: /* MSI used as PLL clock source */
|
|
pllvco = (msirange / pllm);
|
|
break;
|
|
}
|
|
pllvco = pllvco * ((RCC->PLLCFGR & RCC_PLLCFGR_PLLN) >> 8U);
|
|
pllr = (((RCC->PLLCFGR & RCC_PLLCFGR_PLLR) >> 25U) + 1U) * 2U;
|
|
SystemCoreClock = pllvco/pllr;
|
|
break;
|
|
|
|
default:
|
|
SystemCoreClock = msirange;
|
|
break;
|
|
}
|
|
/* Compute HCLK clock frequency --------------------------------------------*/
|
|
/* Get HCLK prescaler */
|
|
tmp = AHBPrescTable[((RCC->CFGR & RCC_CFGR_HPRE) >> 4U)];
|
|
/* HCLK clock frequency */
|
|
SystemCoreClock >>= tmp;
|
|
}
|
|
|
|
|
|
/**
|
|
* @}
|
|
*/
|
|
|
|
/**
|
|
* @}
|
|
*/
|
|
|
|
/**
|
|
* @}
|
|
*/
|
|
|
|
/************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/
|