Tux Leon / mbed-dev

mbed library sources. Supersedes mbed-src.

Fork of mbed-dev by mbed official

targets/TARGET_STM/TARGET_STM32L4/device/system_stm32l4xx.c@181:96ed750bd169, 2018-01-17 (annotated)

Committer:
Anna Bridge
Date:
Wed Jan 17 15:23:54 2018 +0000
Revision:
181:96ed750bd169
Parent:
170:19eb464bc2be 
mbed-dev libray. Release version 158

Who changed what in which revision?

UserRevisionLine numberNew contents of line
Kojto 170:19eb464bc2be 1 /**
Kojto 170:19eb464bc2be 2 ******************************************************************************
Kojto 170:19eb464bc2be 3 * @file system_stm32l4xx.c
Kojto 170:19eb464bc2be 4 * @author MCD Application Team
Kojto 170:19eb464bc2be 5 * @version V1.3.1
Kojto 170:19eb464bc2be 6 * @date 21-April-2017
Kojto 170:19eb464bc2be 7 * @brief CMSIS Cortex-M4 Device Peripheral Access Layer System Source File
Kojto 170:19eb464bc2be 8 *
Kojto 170:19eb464bc2be 9 * This file provides two functions and one global variable to be called from
Kojto 170:19eb464bc2be 10 * user application:
Kojto 170:19eb464bc2be 11 * - SystemInit(): This function is called at startup just after reset and
Kojto 170:19eb464bc2be 12 * before branch to main program. This call is made inside
Kojto 170:19eb464bc2be 13 * the "startup_stm32l4xx.s" file.
Kojto 170:19eb464bc2be 14 *
Kojto 170:19eb464bc2be 15 * - SystemCoreClock variable: Contains the core clock (HCLK), it can be used
Kojto 170:19eb464bc2be 16 * by the user application to setup the SysTick
Kojto 170:19eb464bc2be 17 * timer or configure other parameters.
Kojto 170:19eb464bc2be 18 *
Kojto 170:19eb464bc2be 19 * - SystemCoreClockUpdate(): Updates the variable SystemCoreClock and must
Kojto 170:19eb464bc2be 20 * be called whenever the core clock is changed
Kojto 170:19eb464bc2be 21 * during program execution.
Kojto 170:19eb464bc2be 22 *
Kojto 170:19eb464bc2be 23 * After each device reset the MSI (4 MHz) is used as system clock source.
Kojto 170:19eb464bc2be 24 * Then SystemInit() function is called, in "startup_stm32l4xx.s" file, to
Kojto 170:19eb464bc2be 25 * configure the system clock before to branch to main program.
Kojto 170:19eb464bc2be 26 *
Kojto 170:19eb464bc2be 27 * This file configures the system clock as follows:
Kojto 170:19eb464bc2be 28 *=============================================================================
Kojto 170:19eb464bc2be 29 *-----------------------------------------------------------------------------
Kojto 170:19eb464bc2be 30 * System Clock source | MSI
Kojto 170:19eb464bc2be 31 *-----------------------------------------------------------------------------
Kojto 170:19eb464bc2be 32 * SYSCLK(Hz) | 4000000
Kojto 170:19eb464bc2be 33 *-----------------------------------------------------------------------------
Kojto 170:19eb464bc2be 34 * HCLK(Hz) | 4000000
Kojto 170:19eb464bc2be 35 *-----------------------------------------------------------------------------
Kojto 170:19eb464bc2be 36 * AHB Prescaler | 1
Kojto 170:19eb464bc2be 37 *-----------------------------------------------------------------------------
Kojto 170:19eb464bc2be 38 * APB1 Prescaler | 1
Kojto 170:19eb464bc2be 39 *-----------------------------------------------------------------------------
Kojto 170:19eb464bc2be 40 * APB2 Prescaler | 1
Kojto 170:19eb464bc2be 41 *-----------------------------------------------------------------------------
Kojto 170:19eb464bc2be 42 * PLL_M | 1
Kojto 170:19eb464bc2be 43 *-----------------------------------------------------------------------------
Kojto 170:19eb464bc2be 44 * PLL_N | 8
Kojto 170:19eb464bc2be 45 *-----------------------------------------------------------------------------
Kojto 170:19eb464bc2be 46 * PLL_P | 7
Kojto 170:19eb464bc2be 47 *-----------------------------------------------------------------------------
Kojto 170:19eb464bc2be 48 * PLL_Q | 2
Kojto 170:19eb464bc2be 49 *-----------------------------------------------------------------------------
Kojto 170:19eb464bc2be 50 * PLL_R | 2
Kojto 170:19eb464bc2be 51 *-----------------------------------------------------------------------------
Kojto 170:19eb464bc2be 52 * PLLSAI1_P | NA
Kojto 170:19eb464bc2be 53 *-----------------------------------------------------------------------------
Kojto 170:19eb464bc2be 54 * PLLSAI1_Q | NA
Kojto 170:19eb464bc2be 55 *-----------------------------------------------------------------------------
Kojto 170:19eb464bc2be 56 * PLLSAI1_R | NA
Kojto 170:19eb464bc2be 57 *-----------------------------------------------------------------------------
Kojto 170:19eb464bc2be 58 * PLLSAI2_P | NA
Kojto 170:19eb464bc2be 59 *-----------------------------------------------------------------------------
Kojto 170:19eb464bc2be 60 * PLLSAI2_Q | NA
Kojto 170:19eb464bc2be 61 *-----------------------------------------------------------------------------
Kojto 170:19eb464bc2be 62 * PLLSAI2_R | NA
Kojto 170:19eb464bc2be 63 *-----------------------------------------------------------------------------
Kojto 170:19eb464bc2be 64 * Require 48MHz for USB OTG FS, | Disabled
Kojto 170:19eb464bc2be 65 * SDIO and RNG clock |
Kojto 170:19eb464bc2be 66 *-----------------------------------------------------------------------------
Kojto 170:19eb464bc2be 67 *=============================================================================
Kojto 170:19eb464bc2be 68 ******************************************************************************
Kojto 170:19eb464bc2be 69 * @attention
Kojto 170:19eb464bc2be 70 *
Kojto 170:19eb464bc2be 71 * <h2><center>&copy; COPYRIGHT(c) 2017 STMicroelectronics</center></h2>
Kojto 170:19eb464bc2be 72 *
Kojto 170:19eb464bc2be 73 * Redistribution and use in source and binary forms, with or without modification,
Kojto 170:19eb464bc2be 74 * are permitted provided that the following conditions are met:
Kojto 170:19eb464bc2be 75 * 1. Redistributions of source code must retain the above copyright notice,
Kojto 170:19eb464bc2be 76 * this list of conditions and the following disclaimer.
Kojto 170:19eb464bc2be 77 * 2. Redistributions in binary form must reproduce the above copyright notice,
Kojto 170:19eb464bc2be 78 * this list of conditions and the following disclaimer in the documentation
Kojto 170:19eb464bc2be 79 * and/or other materials provided with the distribution.
Kojto 170:19eb464bc2be 80 * 3. Neither the name of STMicroelectronics nor the names of its contributors
Kojto 170:19eb464bc2be 81 * may be used to endorse or promote products derived from this software
Kojto 170:19eb464bc2be 82 * without specific prior written permission.
Kojto 170:19eb464bc2be 83 *
Kojto 170:19eb464bc2be 84 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
Kojto 170:19eb464bc2be 85 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
Kojto 170:19eb464bc2be 86 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
Kojto 170:19eb464bc2be 87 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
Kojto 170:19eb464bc2be 88 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
Kojto 170:19eb464bc2be 89 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
Kojto 170:19eb464bc2be 90 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
Kojto 170:19eb464bc2be 91 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
Kojto 170:19eb464bc2be 92 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
Kojto 170:19eb464bc2be 93 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
Kojto 170:19eb464bc2be 94 *
Kojto 170:19eb464bc2be 95 ******************************************************************************
Kojto 170:19eb464bc2be 96 */
Kojto 170:19eb464bc2be 97
Kojto 170:19eb464bc2be 98 /** @addtogroup CMSIS
Kojto 170:19eb464bc2be 99 * @{
Kojto 170:19eb464bc2be 100 */
Kojto 170:19eb464bc2be 101
Kojto 170:19eb464bc2be 102 /** @addtogroup stm32l4xx_system
Kojto 170:19eb464bc2be 103 * @{
Kojto 170:19eb464bc2be 104 */
Kojto 170:19eb464bc2be 105
Kojto 170:19eb464bc2be 106 /** @addtogroup STM32L4xx_System_Private_Includes
Kojto 170:19eb464bc2be 107 * @{
Kojto 170:19eb464bc2be 108 */
Kojto 170:19eb464bc2be 109
Kojto 170:19eb464bc2be 110 #include "stm32l4xx.h"
Kojto 170:19eb464bc2be 111
Kojto 170:19eb464bc2be 112 #if !defined (HSE_VALUE)
Kojto 170:19eb464bc2be 113 #define HSE_VALUE ((uint32_t)8000000) /*!< Value of the External oscillator in Hz */
Kojto 170:19eb464bc2be 114 #endif /* HSE_VALUE */
Kojto 170:19eb464bc2be 115
Kojto 170:19eb464bc2be 116 #if !defined (MSI_VALUE)
Kojto 170:19eb464bc2be 117 #define MSI_VALUE ((uint32_t)4000000) /*!< Value of the Internal oscillator in Hz*/
Kojto 170:19eb464bc2be 118 #endif /* MSI_VALUE */
Kojto 170:19eb464bc2be 119
Kojto 170:19eb464bc2be 120 #if !defined (HSI_VALUE)
Kojto 170:19eb464bc2be 121 #define HSI_VALUE ((uint32_t)16000000) /*!< Value of the Internal oscillator in Hz*/
Kojto 170:19eb464bc2be 122 #endif /* HSI_VALUE */
Kojto 170:19eb464bc2be 123
Kojto 170:19eb464bc2be 124 /**
Kojto 170:19eb464bc2be 125 * @}
Kojto 170:19eb464bc2be 126 */
Kojto 170:19eb464bc2be 127
Kojto 170:19eb464bc2be 128 /** @addtogroup STM32L4xx_System_Private_TypesDefinitions
Kojto 170:19eb464bc2be 129 * @{
Kojto 170:19eb464bc2be 130 */
Kojto 170:19eb464bc2be 131
Kojto 170:19eb464bc2be 132 /**
Kojto 170:19eb464bc2be 133 * @}
Kojto 170:19eb464bc2be 134 */
Kojto 170:19eb464bc2be 135
Kojto 170:19eb464bc2be 136 /** @addtogroup STM32L4xx_System_Private_Defines
Kojto 170:19eb464bc2be 137 * @{
Kojto 170:19eb464bc2be 138 */
Kojto 170:19eb464bc2be 139
Kojto 170:19eb464bc2be 140 /************************* Miscellaneous Configuration ************************/
Kojto 170:19eb464bc2be 141 /*!< Uncomment the following line if you need to relocate your vector Table in
Kojto 170:19eb464bc2be 142 Internal SRAM. */
Kojto 170:19eb464bc2be 143 /* #define VECT_TAB_SRAM */
Kojto 170:19eb464bc2be 144 #define VECT_TAB_OFFSET 0x00 /*!< Vector Table base offset field.
Kojto 170:19eb464bc2be 145 This value must be a multiple of 0x200. */
Kojto 170:19eb464bc2be 146 /******************************************************************************/
Kojto 170:19eb464bc2be 147 /**
Kojto 170:19eb464bc2be 148 * @}
Kojto 170:19eb464bc2be 149 */
Kojto 170:19eb464bc2be 150
Kojto 170:19eb464bc2be 151 /** @addtogroup STM32L4xx_System_Private_Macros
Kojto 170:19eb464bc2be 152 * @{
Kojto 170:19eb464bc2be 153 */
Kojto 170:19eb464bc2be 154
Kojto 170:19eb464bc2be 155 /**
Kojto 170:19eb464bc2be 156 * @}
Kojto 170:19eb464bc2be 157 */
Kojto 170:19eb464bc2be 158
Kojto 170:19eb464bc2be 159 /** @addtogroup STM32L4xx_System_Private_Variables
Kojto 170:19eb464bc2be 160 * @{
Kojto 170:19eb464bc2be 161 */
Kojto 170:19eb464bc2be 162 /* The SystemCoreClock variable is updated in three ways:
Kojto 170:19eb464bc2be 163 1) by calling CMSIS function SystemCoreClockUpdate()
Kojto 170:19eb464bc2be 164 2) by calling HAL API function HAL_RCC_GetHCLKFreq()
Kojto 170:19eb464bc2be 165 3) each time HAL_RCC_ClockConfig() is called to configure the system clock frequency
Kojto 170:19eb464bc2be 166 Note: If you use this function to configure the system clock; then there
Kojto 170:19eb464bc2be 167 is no need to call the 2 first functions listed above, since SystemCoreClock
Kojto 170:19eb464bc2be 168 variable is updated automatically.
Kojto 170:19eb464bc2be 169 */
Kojto 170:19eb464bc2be 170 uint32_t SystemCoreClock = 4000000;
Kojto 170:19eb464bc2be 171
Kojto 170:19eb464bc2be 172 const uint8_t AHBPrescTable[16] = {0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 6, 7, 8, 9};
Kojto 170:19eb464bc2be 173 const uint8_t APBPrescTable[8] = {0, 0, 0, 0, 1, 2, 3, 4};
Kojto 170:19eb464bc2be 174 const uint32_t MSIRangeTable[12] = {100000, 200000, 400000, 800000, 1000000, 2000000, \
Kojto 170:19eb464bc2be 175 4000000, 8000000, 16000000, 24000000, 32000000, 48000000};
Kojto 170:19eb464bc2be 176 /**
Kojto 170:19eb464bc2be 177 * @}
Kojto 170:19eb464bc2be 178 */
Kojto 170:19eb464bc2be 179
Kojto 170:19eb464bc2be 180 /** @addtogroup STM32L4xx_System_Private_FunctionPrototypes
Kojto 170:19eb464bc2be 181 * @{
Kojto 170:19eb464bc2be 182 */
Kojto 170:19eb464bc2be 183
Kojto 170:19eb464bc2be 184 /**
Kojto 170:19eb464bc2be 185 * @}
Kojto 170:19eb464bc2be 186 */
Kojto 170:19eb464bc2be 187
Kojto 170:19eb464bc2be 188 /** @addtogroup STM32L4xx_System_Private_Functions
Kojto 170:19eb464bc2be 189 * @{
Kojto 170:19eb464bc2be 190 */
Kojto 170:19eb464bc2be 191
Kojto 170:19eb464bc2be 192 /*+ MBED */
Kojto 170:19eb464bc2be 193 #if 0
Kojto 170:19eb464bc2be 194 /*- MBED */
Kojto 170:19eb464bc2be 195
Kojto 170:19eb464bc2be 196 /**
Kojto 170:19eb464bc2be 197 * @brief Setup the microcontroller system.
Kojto 170:19eb464bc2be 198 * @param None
Kojto 170:19eb464bc2be 199 * @retval None
Kojto 170:19eb464bc2be 200 */
Kojto 170:19eb464bc2be 201
Kojto 170:19eb464bc2be 202 void SystemInit(void)
Kojto 170:19eb464bc2be 203 {
Kojto 170:19eb464bc2be 204 /* FPU settings ------------------------------------------------------------*/
Kojto 170:19eb464bc2be 205 #if (__FPU_PRESENT == 1) && (__FPU_USED == 1)
Kojto 170:19eb464bc2be 206 SCB->CPACR |= ((3UL << 10*2)|(3UL << 11*2)); /* set CP10 and CP11 Full Access */
Kojto 170:19eb464bc2be 207 #endif
Kojto 170:19eb464bc2be 208 /* Reset the RCC clock configuration to the default reset state ------------*/
Kojto 170:19eb464bc2be 209 /* Set MSION bit */
Kojto 170:19eb464bc2be 210 RCC->CR |= RCC_CR_MSION;
Kojto 170:19eb464bc2be 211
Kojto 170:19eb464bc2be 212 /* Reset CFGR register */
Kojto 170:19eb464bc2be 213 RCC->CFGR = 0x00000000;
Kojto 170:19eb464bc2be 214
Kojto 170:19eb464bc2be 215 /* Reset HSEON, CSSON , HSION, and PLLON bits */
Kojto 170:19eb464bc2be 216 RCC->CR &= (uint32_t)0xEAF6FFFF;
Kojto 170:19eb464bc2be 217
Kojto 170:19eb464bc2be 218 /* Reset PLLCFGR register */
Kojto 170:19eb464bc2be 219 RCC->PLLCFGR = 0x00001000;
Kojto 170:19eb464bc2be 220
Kojto 170:19eb464bc2be 221 /* Reset HSEBYP bit */
Kojto 170:19eb464bc2be 222 RCC->CR &= (uint32_t)0xFFFBFFFF;
Kojto 170:19eb464bc2be 223
Kojto 170:19eb464bc2be 224 /* Disable all interrupts */
Kojto 170:19eb464bc2be 225 RCC->CIER = 0x00000000;
Kojto 170:19eb464bc2be 226
Kojto 170:19eb464bc2be 227 /* Configure the Vector Table location add offset address ------------------*/
Kojto 170:19eb464bc2be 228 #ifdef VECT_TAB_SRAM
Kojto 170:19eb464bc2be 229 SCB->VTOR = SRAM_BASE | VECT_TAB_OFFSET; /* Vector Table Relocation in Internal SRAM */
Kojto 170:19eb464bc2be 230 #else
Kojto 170:19eb464bc2be 231 SCB->VTOR = FLASH_BASE | VECT_TAB_OFFSET; /* Vector Table Relocation in Internal FLASH */
Kojto 170:19eb464bc2be 232 #endif
Kojto 170:19eb464bc2be 233 }
Kojto 170:19eb464bc2be 234
Kojto 170:19eb464bc2be 235 /*+ MBED */
Kojto 170:19eb464bc2be 236 #endif
Kojto 170:19eb464bc2be 237 /*- MBED */
Kojto 170:19eb464bc2be 238
Kojto 170:19eb464bc2be 239 /**
Kojto 170:19eb464bc2be 240 * @brief Update SystemCoreClock variable according to Clock Register Values.
Kojto 170:19eb464bc2be 241 * The SystemCoreClock variable contains the core clock (HCLK), it can
Kojto 170:19eb464bc2be 242 * be used by the user application to setup the SysTick timer or configure
Kojto 170:19eb464bc2be 243 * other parameters.
Kojto 170:19eb464bc2be 244 *
Kojto 170:19eb464bc2be 245 * @note Each time the core clock (HCLK) changes, this function must be called
Kojto 170:19eb464bc2be 246 * to update SystemCoreClock variable value. Otherwise, any configuration
Kojto 170:19eb464bc2be 247 * based on this variable will be incorrect.
Kojto 170:19eb464bc2be 248 *
Kojto 170:19eb464bc2be 249 * @note - The system frequency computed by this function is not the real
Kojto 170:19eb464bc2be 250 * frequency in the chip. It is calculated based on the predefined
Kojto 170:19eb464bc2be 251 * constant and the selected clock source:
Kojto 170:19eb464bc2be 252 *
Kojto 170:19eb464bc2be 253 * - If SYSCLK source is MSI, SystemCoreClock will contain the MSI_VALUE(*)
Kojto 170:19eb464bc2be 254 *
Kojto 170:19eb464bc2be 255 * - If SYSCLK source is HSI, SystemCoreClock will contain the HSI_VALUE(**)
Kojto 170:19eb464bc2be 256 *
Kojto 170:19eb464bc2be 257 * - If SYSCLK source is HSE, SystemCoreClock will contain the HSE_VALUE(***)
Kojto 170:19eb464bc2be 258 *
Kojto 170:19eb464bc2be 259 * - If SYSCLK source is PLL, SystemCoreClock will contain the HSE_VALUE(***)
Kojto 170:19eb464bc2be 260 * or HSI_VALUE(*) or MSI_VALUE(*) multiplied/divided by the PLL factors.
Kojto 170:19eb464bc2be 261 *
Kojto 170:19eb464bc2be 262 * (*) MSI_VALUE is a constant defined in stm32l4xx_hal.h file (default value
Kojto 170:19eb464bc2be 263 * 4 MHz) but the real value may vary depending on the variations
Kojto 170:19eb464bc2be 264 * in voltage and temperature.
Kojto 170:19eb464bc2be 265 *
Kojto 170:19eb464bc2be 266 * (**) HSI_VALUE is a constant defined in stm32l4xx_hal.h file (default value
Kojto 170:19eb464bc2be 267 * 16 MHz) but the real value may vary depending on the variations
Kojto 170:19eb464bc2be 268 * in voltage and temperature.
Kojto 170:19eb464bc2be 269 *
Kojto 170:19eb464bc2be 270 * (***) HSE_VALUE is a constant defined in stm32l4xx_hal.h file (default value
Kojto 170:19eb464bc2be 271 * 8 MHz), user has to ensure that HSE_VALUE is same as the real
Kojto 170:19eb464bc2be 272 * frequency of the crystal used. Otherwise, this function may
Kojto 170:19eb464bc2be 273 * have wrong result.
Kojto 170:19eb464bc2be 274 *
Kojto 170:19eb464bc2be 275 * - The result of this function could be not correct when using fractional
Kojto 170:19eb464bc2be 276 * value for HSE crystal.
Kojto 170:19eb464bc2be 277 *
Kojto 170:19eb464bc2be 278 * @param None
Kojto 170:19eb464bc2be 279 * @retval None
Kojto 170:19eb464bc2be 280 */
Kojto 170:19eb464bc2be 281 void SystemCoreClockUpdate(void)
Kojto 170:19eb464bc2be 282 {
Kojto 170:19eb464bc2be 283 uint32_t tmp = 0, msirange = 0, pllvco = 0, pllr = 2, pllsource = 0, pllm = 2;
Kojto 170:19eb464bc2be 284
Kojto 170:19eb464bc2be 285 /* Get MSI Range frequency--------------------------------------------------*/
Kojto 170:19eb464bc2be 286 if((RCC->CR & RCC_CR_MSIRGSEL) == RESET)
Kojto 170:19eb464bc2be 287 { /* MSISRANGE from RCC_CSR applies */
Kojto 170:19eb464bc2be 288 msirange = (RCC->CSR & RCC_CSR_MSISRANGE) >> 8;
Kojto 170:19eb464bc2be 289 }
Kojto 170:19eb464bc2be 290 else
Kojto 170:19eb464bc2be 291 { /* MSIRANGE from RCC_CR applies */
Kojto 170:19eb464bc2be 292 msirange = (RCC->CR & RCC_CR_MSIRANGE) >> 4;
Kojto 170:19eb464bc2be 293 }
Kojto 170:19eb464bc2be 294 /*MSI frequency range in HZ*/
Kojto 170:19eb464bc2be 295 msirange = MSIRangeTable[msirange];
Kojto 170:19eb464bc2be 296
Kojto 170:19eb464bc2be 297 /* Get SYSCLK source -------------------------------------------------------*/
Kojto 170:19eb464bc2be 298 switch (RCC->CFGR & RCC_CFGR_SWS)
Kojto 170:19eb464bc2be 299 {
Kojto 170:19eb464bc2be 300 case 0x00: /* MSI used as system clock source */
Kojto 170:19eb464bc2be 301 SystemCoreClock = msirange;
Kojto 170:19eb464bc2be 302 break;
Kojto 170:19eb464bc2be 303
Kojto 170:19eb464bc2be 304 case 0x04: /* HSI used as system clock source */
Kojto 170:19eb464bc2be 305 SystemCoreClock = HSI_VALUE;
Kojto 170:19eb464bc2be 306 break;
Kojto 170:19eb464bc2be 307
Kojto 170:19eb464bc2be 308 case 0x08: /* HSE used as system clock source */
Kojto 170:19eb464bc2be 309 SystemCoreClock = HSE_VALUE;
Kojto 170:19eb464bc2be 310 break;
Kojto 170:19eb464bc2be 311
Kojto 170:19eb464bc2be 312 case 0x0C: /* PLL used as system clock source */
Kojto 170:19eb464bc2be 313 /* PLL_VCO = (HSE_VALUE or HSI_VALUE or MSI_VALUE/ PLLM) * PLLN
Kojto 170:19eb464bc2be 314 SYSCLK = PLL_VCO / PLLR
Kojto 170:19eb464bc2be 315 */
Kojto 170:19eb464bc2be 316 pllsource = (RCC->PLLCFGR & RCC_PLLCFGR_PLLSRC);
Kojto 170:19eb464bc2be 317 pllm = ((RCC->PLLCFGR & RCC_PLLCFGR_PLLM) >> 4) + 1 ;
Kojto 170:19eb464bc2be 318
Kojto 170:19eb464bc2be 319 switch (pllsource)
Kojto 170:19eb464bc2be 320 {
Kojto 170:19eb464bc2be 321 case 0x02: /* HSI used as PLL clock source */
Kojto 170:19eb464bc2be 322 pllvco = (HSI_VALUE / pllm);
Kojto 170:19eb464bc2be 323 break;
Kojto 170:19eb464bc2be 324
Kojto 170:19eb464bc2be 325 case 0x03: /* HSE used as PLL clock source */
Kojto 170:19eb464bc2be 326 pllvco = (HSE_VALUE / pllm);
Kojto 170:19eb464bc2be 327 break;
Kojto 170:19eb464bc2be 328
Kojto 170:19eb464bc2be 329 default: /* MSI used as PLL clock source */
Kojto 170:19eb464bc2be 330 pllvco = (msirange / pllm);
Kojto 170:19eb464bc2be 331 break;
Kojto 170:19eb464bc2be 332 }
Kojto 170:19eb464bc2be 333 pllvco = pllvco * ((RCC->PLLCFGR & RCC_PLLCFGR_PLLN) >> 8);
Kojto 170:19eb464bc2be 334 pllr = (((RCC->PLLCFGR & RCC_PLLCFGR_PLLR) >> 25) + 1) * 2;
Kojto 170:19eb464bc2be 335 SystemCoreClock = pllvco/pllr;
Kojto 170:19eb464bc2be 336 break;
Kojto 170:19eb464bc2be 337
Kojto 170:19eb464bc2be 338 default:
Kojto 170:19eb464bc2be 339 SystemCoreClock = msirange;
Kojto 170:19eb464bc2be 340 break;
Kojto 170:19eb464bc2be 341 }
Kojto 170:19eb464bc2be 342 /* Compute HCLK clock frequency --------------------------------------------*/
Kojto 170:19eb464bc2be 343 /* Get HCLK prescaler */
Kojto 170:19eb464bc2be 344 tmp = AHBPrescTable[((RCC->CFGR & RCC_CFGR_HPRE) >> 4)];
Kojto 170:19eb464bc2be 345 /* HCLK clock frequency */
Kojto 170:19eb464bc2be 346 SystemCoreClock >>= tmp;
Kojto 170:19eb464bc2be 347 }
Kojto 170:19eb464bc2be 348
Kojto 170:19eb464bc2be 349
Kojto 170:19eb464bc2be 350 /**
Kojto 170:19eb464bc2be 351 * @}
Kojto 170:19eb464bc2be 352 */
Kojto 170:19eb464bc2be 353
Kojto 170:19eb464bc2be 354 /**
Kojto 170:19eb464bc2be 355 * @}
Kojto 170:19eb464bc2be 356 */
Kojto 170:19eb464bc2be 357
Kojto 170:19eb464bc2be 358 /**
Kojto 170:19eb464bc2be 359 * @}
Kojto 170:19eb464bc2be 360 */
Kojto 170:19eb464bc2be 361
Kojto 170:19eb464bc2be 362 /************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/