/**
******************************************************************************
* @file system_stm32f0xx.c
* @author MCD Application Team
* @version V2.3.1
* @date 04-November-2016
* @brief CMSIS Cortex-M0 Device Peripheral Access Layer System Source File.
*
* 1. 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_stm32f0xx.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.
*
* 2. After each device reset the HSI (8 MHz) is used as system clock source.
* Then SystemInit() function is called, in "startup_stm32f0xx.s" file, to
* configure the system clock before to branch to main program.
*
* 3. This file configures the system clock as follows:
*=============================================================================
* Supported STM32F0xx device
*-----------------------------------------------------------------------------
* System Clock source | HSI
*-----------------------------------------------------------------------------
* SYSCLK(Hz) | 8000000
*-----------------------------------------------------------------------------
* HCLK(Hz) | 8000000
*-----------------------------------------------------------------------------
* AHB Prescaler | 1
*-----------------------------------------------------------------------------
* APB1 Prescaler | 1
*-----------------------------------------------------------------------------
*=============================================================================
******************************************************************************
* @attention
*
* <h2><center>© COPYRIGHT(c) 2016 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 stm32f0xx_system
* @{
*/
/** @addtogroup STM32F0xx_System_Private_Includes
* @{
*/
#include "stm32f0xx.h"
/**
* @}
*/
/** @addtogroup STM32F0xx_System_Private_TypesDefinitions
* @{
*/
/**
* @}
*/
/** @addtogroup STM32F0xx_System_Private_Defines
* @{
*/
#if !defined (HSE_VALUE)
#define HSE_VALUE ((uint32_t)8000000) /*!< Default value of the External oscillator in Hz.
This value can be provided and adapted by the user application. */
#endif /* HSE_VALUE */
#if !defined (HSI_VALUE)
#define HSI_VALUE ((uint32_t)8000000) /*!< Default value of the Internal oscillator in Hz.
This value can be provided and adapted by the user application. */
#endif /* HSI_VALUE */
#if !defined (HSI48_VALUE)
#define HSI48_VALUE ((uint32_t)48000000) /*!< Default value of the HSI48 Internal oscillator in Hz.
This value can be provided and adapted by the user application. */
#endif /* HSI48_VALUE */
/**
* @}
*/
/** @addtogroup STM32F0xx_System_Private_Macros
* @{
*/
/**
* @}
*/
/** @addtogroup STM32F0xx_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 there is no need to
call the 2 first functions listed above, since SystemCoreClock variable is
updated automatically.
*/
uint32_t SystemCoreClock = 8000000;
const uint8_t AHBPrescTable[16] = {0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 6, 7, 8, 9};
const uint8_t APBPrescTable[8] = {0, 0, 0, 0, 1, 2, 3, 4};
/**
* @}
*/
/** @addtogroup STM32F0xx_System_Private_FunctionPrototypes
* @{
*/
/**
* @}
*/
/** @addtogroup STM32F0xx_System_Private_Functions
* @{
*/
/**
* @brief Setup the microcontroller system.
* Initialize the default HSI clock source, vector table location and the PLL configuration is reset.
* @param None
* @retval None
*/
void SystemInit(void)
{
/* Reset the RCC clock configuration to the default reset state ------------*/
/* Set HSION bit */
RCC->CR |= (uint32_t)0x00000001U;
#if defined (STM32F051x8) || defined (STM32F058x8)
/* Reset SW[1:0], HPRE[3:0], PPRE[2:0], ADCPRE and MCOSEL[2:0] bits */
RCC->CFGR &= (uint32_t)0xF8FFB80CU;
#else
/* Reset SW[1:0], HPRE[3:0], PPRE[2:0], ADCPRE, MCOSEL[2:0], MCOPRE[2:0] and PLLNODIV bits */
RCC->CFGR &= (uint32_t)0x08FFB80CU;
#endif /* STM32F051x8 or STM32F058x8 */
/* Reset HSEON, CSSON and PLLON bits */
RCC->CR &= (uint32_t)0xFEF6FFFFU;
/* Reset HSEBYP bit */
RCC->CR &= (uint32_t)0xFFFBFFFFU;
/* Reset PLLSRC, PLLXTPRE and PLLMUL[3:0] bits */
RCC->CFGR &= (uint32_t)0xFFC0FFFFU;
/* Reset PREDIV[3:0] bits */
RCC->CFGR2 &= (uint32_t)0xFFFFFFF0U;
#if defined (STM32F072xB) || defined (STM32F078xx)
/* Reset USART2SW[1:0], USART1SW[1:0], I2C1SW, CECSW, USBSW and ADCSW bits */
RCC->CFGR3 &= (uint32_t)0xFFFCFE2CU;
#elif defined (STM32F071xB)
/* Reset USART2SW[1:0], USART1SW[1:0], I2C1SW, CECSW and ADCSW bits */
RCC->CFGR3 &= (uint32_t)0xFFFFCEACU;
#elif defined (STM32F091xC) || defined (STM32F098xx)
/* Reset USART3SW[1:0], USART2SW[1:0], USART1SW[1:0], I2C1SW, CECSW and ADCSW bits */
RCC->CFGR3 &= (uint32_t)0xFFF0FEACU;
#elif defined