/**
******************************************************************************
* @file system_stm32f1xx.c
* @author MCD Application Team
* @brief CMSIS Cortex-M3 Device Peripheral Access Layer System Source File.
*
* 1. This file provides two functions and one global variable to be called from
* user application:
* - SystemInit(): Setups the system clock (System clock source, PLL Multiplier
* factors, AHB/APBx prescalers and Flash settings).
* This function is called at startup just after reset and
* before branch to main program. This call is made inside
* the "startup_stm32f1xx_xx.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_stm32f1xx_xx.s" file, to
* configure the system clock before to branch to main program.
*
* 4. The default value of HSE crystal is set to 8 MHz (or 25 MHz, depending on
* the product used), refer to "HSE_VALUE".
* When HSE is used as system clock source, directly or through PLL, and you
* are using different crystal you have to adapt the HSE value to your own
* configuration.
*
******************************************************************************
* @attention
*
* <h2><center>© Copyright (c) 2017 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 stm32f1xx_system
* @{
*/
/** @addtogroup STM32F1xx_System_Private_Includes
* @{
*/
#include "stm32f1xx.h"
/**
* @}
*/
/** @addtogroup STM32F1xx_System_Private_TypesDefinitions
* @{
*/
/**
* @}
*/
/** @addtogroup STM32F1xx_System_Private_Defines
* @{
*/
#if !defined (HSE_VALUE)
#define HSE_VALUE 8000000U /*!< 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 8000000U /*!< Default value of the Internal oscillator in Hz.
This value can be provided and adapted by the user application. */
#endif /* HSI_VALUE */
/*!< Uncomment the following line if you need to use external SRAM */
#if defined(STM32F100xE) || defined(STM32F101xE) || defined(STM32F101xG) || defined(STM32F103xE) || defined(STM32F103xG)
/* #define DATA_IN_ExtSRAM */
#endif /* STM32F100xE || STM32F101xE || STM32F101xG || STM32F103xE || STM32F103xG */
/*!< Uncomment the following line if you need to relocate your vector Table in
Internal SRAM. */
/* #define VECT_TAB_SRAM */
#define VECT_TAB_OFFSET 0x00000000U /*!< Vector Table base offset field.
This value must be a multiple of 0x200. */
/**
* @}
*/
/** @addtogroup STM32F1xx_System_Private_Macros
* @{
*/
/**
* @}
*/
/** @addtogroup STM32F1xx_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 = 16000000;
const uint8_t AHBPrescTable[16U] = {0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 6, 7, 8, 9};
const uint8_t APBPrescTable[8U] = {0, 0, 0, 0, 1, 2, 3, 4};
/**
* @}
*/
/** @addtogroup STM32F1xx_System_Private_FunctionPrototypes
* @{
*/
#if defined(STM32F100xE) || defined(STM32F101xE) || defined(STM32F101xG) || defined(STM32F103xE) || defined(STM32F103xG)
#ifdef DATA_IN_ExtSRAM
static void SystemInit_ExtMemCtl(void);
#endif /* DATA_IN_ExtSRAM */
#endif /* STM32F100xE || STM32F101xE || STM32F101xG || STM32F103xE || STM32F103xG */
/**
* @}
*/
/** @addtogroup STM32F1xx_System_Private_Functions
* @{
*/
/**
* @brief Setup the microcontroller system
* Initialize the Embedded Flash Interface, the PLL and update the
* SystemCoreClock variable.
* @note This function should be used only after reset.
* @param None
* @retval None
*/
void SystemInit (void)
{
/* Reset the RCC clock configuration to the default reset state(for debug purpose) */
/* Set HSION bit */
RCC->CR |= 0x00000001U;
/* Reset SW, HPRE, PPRE1, PPRE2, ADCPRE and MCO bits */
#if !defined(STM32F105xC) && !defined(STM32F107xC)
RCC->CFGR &= 0xF8FF0000U;
#else
RCC->CFGR &= 0xF0FF0000U;
#endif /* STM32F105xC */
/* Reset HSEON, CSSON and PLLON bits */
RCC->CR &= 0xFEF6FFFFU;
/* Reset HSEBYP bit */
RCC->CR &= 0xFFFBFFFFU;
/* Reset PLLSRC, PLLXTPRE, PLLMUL and USBPRE/OTGFSPRE bits */
RCC->CFGR &= 0xFF80FFFFU;
#if defined(STM32F105xC) || defined(STM32F107xC)
/* Reset PLL2ON and PLL3ON bits */
RCC->CR &= 0xEBFFFFFFU;
/* Disable all interrupts and clear pending bits */
RCC->CIR = 0x00FF0000U;
/* Reset CFGR2 register */
RCC->CFGR2 = 0x00000000U;
#elif defined(STM32F100xB) || defined(STM32F100xE)
/* Disable all interrupts and clear pending bits */
RCC->CIR = 0x009F0000U;
/* Reset CFGR2 register */
RCC->CFGR2 = 0x00000000U;
#else
/* Disable all interrupts and clear pending bits */
RCC->CIR = 0x009F0000U;
#endif /* STM32F105xC */
#if defined(STM32F100xE) || defined(STM32F101xE) || defined(STM32F101xG) || defined(STM32F103xE) || defined(STM32F103xG)
#ifdef DATA_IN_ExtSRAM
SystemInit_ExtMemCtl();
#endif /* DATA_IN_ExtSRAM */
#endif
#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(*)
*
* - 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 by the PLL factors.
*
* (*) HSI_VALUE is a constant defined in stm32f1xx.h file (default value
* 8 MHz) but the real value may vary depending on the variations
* in voltage and temperature.
*
* (**) HSE_VALUE is a constant defined in stm32f1xx.h file (default value
* 8 MHz or 25 MHz, depending on the product used), 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, pllmull = 0U, pllsource = 0U;
#if defined(STM32F105xC) || defined(STM32F107xC)
uint32_t prediv1source = 0U, prediv1factor = 0U, prediv2factor = 0U, pll2mull = 0U;
#endif /* STM32F105xC */
#if defined(STM32F100xB) || defined(STM32F100xE)
uint32_t prediv1factor = 0U;
#endif /* STM32F100xB or STM32F100xE */
/* Get SYSCLK source -------------------------------------------------------*/
tmp = RCC->CFGR & RCC_CFGR_SWS;
switch (tmp)
{
case 0x00U: /* HSI used as system clock */
SystemCoreClock = HSI_VALUE;
break;
case 0x04U: /* HSE used as system clock */
SystemCoreClock = HSE_VALUE;
break;
case 0x08U: /* PLL used as system clock */
/* Get PLL clock source and multiplication factor ----------------------*/
pllmull = RCC->CFGR & RCC_CFGR_PLLMULL;
pllsource = RCC->CFGR & RCC_CFGR_PLLSRC;
#if !defined(STM32F105xC) && !defined(STM32F107xC)
pllmull = ( pllmull >> 18U) + 2U;
if (pllsource == 0x00U)
{
/* HSI oscillator clock divided by 2 selected as PLL clock entry */
SystemCoreClock = (HSI_VALUE >> 1U) * pllmull;
}
else
{
#if defined(STM32F100xB) || defined(STM32F100xE)
prediv1factor = (RCC->CFGR2 & RCC_CFGR2_PREDIV1) + 1U;
/* HSE oscillator clock selected as PREDIV1 clock entry */
SystemCoreClock = (HSE_VALUE / prediv1factor) * pllmull;
#else
/* HSE selected as PLL clock entry */
if ((RCC->CFGR & RCC_CFGR_PLLXTPRE) != (uint32_t)RESET)
{/* HSE oscillator clock divided by 2 */
SystemCoreClock = (HSE_VALUE >> 1U) * pllmull;
}
else
{
SystemCoreClock = HSE_VALUE * pllmull;
}
#endif
}
#else
pllmull = pllmull >> 18U;
if (pllmull != 0x0DU)
{
pllmull += 2U;
}
else
{ /* PLL multiplication factor = PLL input clock * 6.5 */
pllmull = 13U / 2U;
}
if (pllsource == 0x00U)
{
/* HSI oscillator clock divided by 2 selected as PLL clock entry */
SystemCoreClock = (HSI_VALUE >> 1U) * pllmull;
}
else
{/* PREDIV1 selected as PLL clock entry */
/* Get PREDIV1 clock source and division factor */
prediv1source = RCC->CFGR2 & RCC_CFGR2_PREDIV1SRC;
prediv1factor = (RCC->CFGR2 & RCC_CFGR2_PREDIV1) + 1U;
if (prediv1source == 0U)
{
/* HSE oscillator clock selected as PREDIV1 clock entry */
SystemCoreClock = (HSE_VALUE / prediv1factor) * pllmull;
}
else
{/* PLL2 clock selected as PREDIV1 clock entry */
/* Get PREDIV2 division factor and PLL2 multiplication factor */
prediv2factor = ((RCC->CFGR2 & RCC_CFGR2_PREDIV2) >> 4U) + 1U;
pll2mull = ((RCC->CFGR2 & RCC_CFGR2_PLL2MUL) >> 8U) + 2U;
SystemCoreClock = (((HSE_VALUE / prediv2factor) * pll2mull) / prediv1factor) * pllmull;
}
}
#endif /* STM32F105xC */
break;
default:
SystemCoreClock = HSI_VALUE;
break;
}
/* Compute HCLK clock frequency ----------------*/
/* Get HCLK prescaler */
tmp = AHBPrescTable[((RCC->CFGR & RCC_CFGR_HPRE) >> 4U)];
/* HCLK clock frequency */
SystemCoreClock >>= tmp;
}
#if defined(STM32F100xE) || defined(STM32F101xE) || defined(STM32F101xG) || defined(STM32F103xE) || defined(STM32F103xG)
/**
* @brief Setup the external memory controller. Called in startup_stm32f1xx.s
* before jump to __main
* @param None
* @retval None
*/
#ifdef DATA_IN_ExtSRAM
/**
* @brief Setup the external memory controller.
* Called in startup_stm32f1xx_xx.s/.c before jump to main.
* This function configures the external SRAM mounted on STM3210E-EVAL
* board (STM32 High density devices). This SRAM will be used as program
* data memory (including heap and stack).
* @param None
* @retval None
*/
void SystemInit_ExtMemCtl(void)
{
__IO uint32_t tmpreg;
/*!< FSMC Bank1 NOR/SRAM3 is used for the STM3210E-EVAL, if another Bank is
required, then adjust the Register Addresses */
/* Enable FSMC clock */
RCC->AHBENR = 0x00000114U;
/* Delay after an RCC peripheral clock enabling */
tmpreg = READ_BIT(RCC->AHBENR, RCC_AHBENR_FSMCEN);
/* Enable GPIOD, GPIOE, GPIOF and GPIOG clocks */
RCC->APB2ENR = 0x000001E0U;
/* Delay after an RCC peripheral clock enabling */
tmpreg = READ_BIT(RCC->APB2ENR, RCC_APB2ENR_IOPDEN);
(void)(tmpreg);
/* --------------- SRAM Data lines, NOE and NWE configuration ---------------*/
/*---------------- SRAM Address lines configuration -------------------------*/
/*---------------- NOE and NWE configuration --------------------------------*/
/*---------------- NE3 configuration ----------------------------------------*/
/*---------------- NBL0, NBL1 configuration ---------------------------------*/
GPIOD->CRL = 0x44BB44BBU;
GPIOD->CRH = 0xBBBBBBBBU;
GPIOE->CRL = 0xB44444BBU;
GPIOE->CRH = 0xBBBBBBBBU;
GPIOF->CRL = 0x44BBBBBBU;
GPIOF->CRH = 0xBBBB4444U;
GPIOG->CRL = 0x44BBBBBBU;
GPIOG->CRH = 0x444B4B44U;
/*---------------- FSMC Configuration ---------------------------------------*/
/*---------------- Enable FSMC Bank1_SRAM Bank ------------------------------*/
FSMC_Bank1->BTCR[4U] = 0x00001091U;
FSMC_Bank1->BTCR[5U] = 0x00110212U;
}
#endif /* DATA_IN_ExtSRAM */
#endif /* STM32F100xE || STM32F101xE || STM32F101xG || STM32F103xE || STM32F103xG */
/**
* @}
*/
/**
* @}
*/
/**
* @}
*/
/************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/