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LibrePilot/flight/pios/stm32f30x/system.c
Vladimir Zidar bd7641e857 LP-512 Build system changed; ld scripts cleanup
2017-05-25 22:08:35 +02:00

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/**
******************************************************************************
* @file system_stm32f30x.c
* @author MCD Application Team
* @version V1.0.0
* @date 04-September-2012
* @brief CMSIS Cortex-M4 Device Peripheral Access Layer System Source File.
* This file contains the system clock configuration for STM32F30x devices,
* and is generated by the clock configuration tool
* stm32f30x_Clock_Configuration_V1.0.0.xls
*
* 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
* and Divider factors, AHB/APBx prescalers and Flash settings),
* depending on the configuration made in the clock xls tool.
* This function is called at startup just after reset and
* before branch to main program. This call is made inside
* the "startup_stm32f30x.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_stm32f30x.s" file, to
* configure the system clock before to branch to main program.
*
* 3. If the system clock source selected by user fails to startup, the SystemInit()
* function will do nothing and HSI still used as system clock source. User can
* add some code to deal with this issue inside the SetSysClock() function.
*
* 4. The default value of HSE crystal is set to 8MHz, refer to "HSE_VALUE" define
* in "stm32f30x.h" file. 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.
*
* 5. This file configures the system clock as follows:
*=============================================================================
* Supported STM32F30x device
*-----------------------------------------------------------------------------
* System Clock source | PLL (HSE)
*-----------------------------------------------------------------------------
* SYSCLK(Hz) | 72000000
*-----------------------------------------------------------------------------
* HCLK(Hz) | 72000000
*-----------------------------------------------------------------------------
* AHB Prescaler | 1
*-----------------------------------------------------------------------------
* APB2 Prescaler | 1
*-----------------------------------------------------------------------------
* APB1 Prescaler | 2
*-----------------------------------------------------------------------------
* HSE Frequency(Hz) | 8000000
*----------------------------------------------------------------------------
* PLLMUL | 9
*-----------------------------------------------------------------------------
* PREDIV | 1
*-----------------------------------------------------------------------------
* USB Clock | DISABLE
*-----------------------------------------------------------------------------
* Flash Latency(WS) | 2
*-----------------------------------------------------------------------------
* Prefetch Buffer | ON
*-----------------------------------------------------------------------------
*=============================================================================
******************************************************************************
* @attention
*
* <h2><center>&copy; COPYRIGHT 2012 STMicroelectronics</center></h2>
*
* Licensed under MCD-ST Liberty SW License Agreement V2, (the "License");
* You may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.st.com/software_license_agreement_liberty_v2
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
******************************************************************************
*/
/** @addtogroup CMSIS
* @{
*/
/** @addtogroup stm32f30x_system
* @{
*/
/** @addtogroup STM32F30x_System_Private_Includes
* @{
*/
#include "stm32f30x.h"
/**
* @}
*/
/** @addtogroup STM32F30x_System_Private_TypesDefinitions
* @{
*/
/**
* @}
*/
/** @addtogroup STM32F30x_System_Private_Defines
* @{
*/
/*!< Uncomment the following line if you need to relocate your vector Table in
Internal SRAM. */
/* #define VECT_TAB_SRAM */
#define VECT_TAB_OFFSET 0x0 /*!< Vector Table base offset field.
This value must be a multiple of 0x200. */
/**
* @}
*/
/** @addtogroup STM32F30x_System_Private_Macros
* @{
*/
/**
* @}
*/
/** @addtogroup STM32F30x_System_Private_Variables
* @{
*/
uint32_t SystemCoreClock = 72000000;
__I uint8_t AHBPrescTable[16] = { 0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 6, 7, 8, 9 };
/**
* @}
*/
/** @addtogroup STM32F30x_System_Private_FunctionPrototypes
* @{
*/
static void SetSysClock(void);
/**
* @}
*/
/** @addtogroup STM32F30x_System_Private_Functions
* @{
*/
/**
* @brief Setup the microcontroller system
* Initialize the Embedded Flash Interface, the PLL and update the
* SystemFrequency variable.
* @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 HSION bit */
RCC->CR |= (uint32_t)0x00000001;
/* Reset CFGR register */
RCC->CFGR &= 0xF87FC00C;
/* Reset HSEON, CSSON and PLLON bits */
RCC->CR &= (uint32_t)0xFEF6FFFF;
/* Reset HSEBYP bit */
RCC->CR &= (uint32_t)0xFFFBFFFF;
/* Reset PLLSRC, PLLXTPRE, PLLMUL and USBPRE bits */
RCC->CFGR &= (uint32_t)0xFF80FFFF;
/* Reset PREDIV1[3:0] bits */
RCC->CFGR2 &= (uint32_t)0xFFFFFFF0;
/* Reset USARTSW[1:0], I2CSW and TIMs bits */
RCC->CFGR3 &= (uint32_t)0xFF00FCCC;
/* Disable all interrupts */
RCC->CIR = 0x00000000;
/* Configure the System clock source, PLL Multiplier and Divider factors,
AHB/APBx prescalers and Flash settings ----------------------------------*/
SetSysClock();
#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/divided by the PLL factors.
*
* (*) HSI_VALUE is a constant defined in stm32f30x.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 stm32f30x.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 = 0, pllmull = 0, pllsource = 0, prediv1factor = 0;
/* Get SYSCLK source -------------------------------------------------------*/
tmp = RCC->CFGR & RCC_CFGR_SWS;
switch (tmp) {
case 0x00: /* HSI used as system clock */
SystemCoreClock = HSI_VALUE;
break;
case 0x04: /* HSE used as system clock */
SystemCoreClock = HSE_VALUE;
break;
case 0x08: /* PLL used as system clock */
/* Get PLL clock source and multiplication factor ----------------------*/
pllmull = RCC->CFGR & RCC_CFGR_PLLMULL;
pllsource = RCC->CFGR & RCC_CFGR_PLLSRC;
pllmull = (pllmull >> 18) + 2;
if (pllsource == 0x00) {
/* HSI oscillator clock divided by 2 selected as PLL clock entry */
SystemCoreClock = (HSI_VALUE >> 1) * pllmull;
} else {
prediv1factor = (RCC->CFGR2 & RCC_CFGR2_PREDIV1) + 1;
/* HSE oscillator clock selected as PREDIV1 clock entry */
SystemCoreClock = (HSE_VALUE / prediv1factor) * pllmull;
}
break;
default: /* HSI used as system clock */
SystemCoreClock = HSI_VALUE;
break;
}
/* Compute HCLK clock frequency ----------------*/
/* Get HCLK prescaler */
tmp = AHBPrescTable[((RCC->CFGR & RCC_CFGR_HPRE) >> 4)];
/* HCLK clock frequency */
SystemCoreClock >>= tmp;
}
/**
* @brief Configures the System clock source, PLL Multiplier and Divider factors,
* AHB/APBx prescalers and Flash settings
* @note This function should be called only once the RCC clock configuration
* is reset to the default reset state (done in SystemInit() function).
* @param None
* @retval None
*/
static void SetSysClock(void)
{
__IO uint32_t StartUpCounter = 0, HSEStatus = 0;
/******************************************************************************/
/* PLL (clocked by HSE) used as System clock source */
/******************************************************************************/
/* SYSCLK, HCLK, PCLK2 and PCLK1 configuration -----------*/
/* Enable HSE */
#ifdef PIOS_RCC_HSE_BYPASS
RCC->CR |= ((uint32_t)RCC_CR_HSEON | RCC_CR_HSEBYP);
#else
RCC->CR |= ((uint32_t)RCC_CR_HSEON);
#endif /* PIOS_HSE_BYPASS */
/* Wait till HSE is ready and if Time out is reached exit */
do {
HSEStatus = RCC->CR & RCC_CR_HSERDY;
StartUpCounter++;
} while ((HSEStatus == 0) && (StartUpCounter != HSE_STARTUP_TIMEOUT));
if ((RCC->CR & RCC_CR_HSERDY) != RESET) {
HSEStatus = (uint32_t)0x01;
} else {
HSEStatus = (uint32_t)0x00;
}
if (HSEStatus == (uint32_t)0x01) {
/* Enable Prefetch Buffer and set Flash Latency */
FLASH->ACR = FLASH_ACR_PRFTBE | (uint32_t)FLASH_ACR_LATENCY_1;
/* HCLK = SYSCLK / 1 */
RCC->CFGR |= (uint32_t)RCC_CFGR_HPRE_DIV1;
/* PCLK2 = HCLK / 1 */
RCC->CFGR |= (uint32_t)RCC_CFGR_PPRE2_DIV1;
/* PCLK1 = HCLK / 2 */
RCC->CFGR |= (uint32_t)RCC_CFGR_PPRE1_DIV2;
/* PLL configuration */
RCC->CFGR &= (uint32_t)((uint32_t) ~(RCC_CFGR_PLLSRC | RCC_CFGR_PLLXTPRE | RCC_CFGR_PLLMULL));
RCC->CFGR |= (uint32_t)(RCC_CFGR_PLLSRC_PREDIV1 | RCC_CFGR_PLLXTPRE_PREDIV1 | RCC_CFGR_PLLMULL9);
/* Enable PLL */
RCC->CR |= RCC_CR_PLLON;
/* Wait till PLL is ready */
while ((RCC->CR & RCC_CR_PLLRDY) == 0) {}
/* Select PLL as system clock source */
RCC->CFGR &= (uint32_t)((uint32_t) ~(RCC_CFGR_SW));
RCC->CFGR |= (uint32_t)RCC_CFGR_SW_PLL;
/* Wait till PLL is used as system clock source */
while ((RCC->CFGR & (uint32_t)RCC_CFGR_SWS) != (uint32_t)RCC_CFGR_SWS_PLL) {}
} else { /* If HSE fails to start-up, the application will have wrong clock
configuration. User can add here some code to deal with this error */
}
}
/**
* @}
*/
/**
* @}
*/
/**
* @}
*/
/************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/
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