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targets/cmsis/TARGET_STM/TARGET_NUCLEO_L152RE/system_stm32l1xx.c@106:ced8cbb51063, 2014-02-26 (annotated)

Committer:
mbed_official
Date:
Wed Feb 26 09:45:12 2014 +0000
Revision:
106:ced8cbb51063
Parent:
76:aeb1df146756
Child:
129:0182c99221bc
Synchronized with git revision 4222735eff5868389433f0e9271976b39c8115cd



Full URL: https://github.com/mbedmicro/mbed/commit/4222735eff5868389433f0e9271976b39c8115cd/



[NUCLEO_xxx] Update STM32CubeF4 driver V1.0.0 + update license

Who changed what in which revision?

UserRevisionLine numberNew contents of line
mbed_official 76:aeb1df146756 1 /**
mbed_official 76:aeb1df146756 2 ******************************************************************************
mbed_official 76:aeb1df146756 3 * @file system_stm32l1xx.c
mbed_official 76:aeb1df146756 4 * @author MCD Application Team
mbed_official 76:aeb1df146756 5 * @version V1.2.0
mbed_official 76:aeb1df146756 6 * @date 11-January-2014
mbed_official 76:aeb1df146756 7 * @brief CMSIS Cortex-M3 Device Peripheral Access Layer System Source File.
mbed_official 76:aeb1df146756 8 * This file contains the system clock configuration for STM32L1xx Ultra
mbed_official 76:aeb1df146756 9 * Low power devices, and is generated by the clock configuration
mbed_official 76:aeb1df146756 10 * tool STM32L1xx_Clock_Configuration_V1.2.0.xls
mbed_official 76:aeb1df146756 11 *
mbed_official 76:aeb1df146756 12 * 1. This file provides two functions and one global variable to be called from
mbed_official 76:aeb1df146756 13 * user application:
mbed_official 76:aeb1df146756 14 * - SystemInit(): Setups the system clock (System clock source, PLL Multiplier
mbed_official 76:aeb1df146756 15 * and Divider factors, AHB/APBx prescalers and Flash settings),
mbed_official 76:aeb1df146756 16 * depending on the configuration made in the clock xls tool.
mbed_official 76:aeb1df146756 17 * This function is called at startup just after reset and
mbed_official 76:aeb1df146756 18 * before branch to main program. This call is made inside
mbed_official 76:aeb1df146756 19 * the "startup_stm32l1xx_xx.s" file.
mbed_official 76:aeb1df146756 20 *
mbed_official 76:aeb1df146756 21 * - SystemCoreClock variable: Contains the core clock (HCLK), it can be used
mbed_official 76:aeb1df146756 22 * by the user application to setup the SysTick
mbed_official 76:aeb1df146756 23 * timer or configure other parameters.
mbed_official 76:aeb1df146756 24 *
mbed_official 76:aeb1df146756 25 * - SystemCoreClockUpdate(): Updates the variable SystemCoreClock and must
mbed_official 76:aeb1df146756 26 * be called whenever the core clock is changed
mbed_official 76:aeb1df146756 27 * during program execution.
mbed_official 76:aeb1df146756 28 *
mbed_official 76:aeb1df146756 29 * 2. After each device reset the MSI (2.1 MHz Range) is used as system clock source.
mbed_official 76:aeb1df146756 30 * Then SystemInit() function is called, in "startup_stm32l1xx_xx.s" file, to
mbed_official 76:aeb1df146756 31 * configure the system clock before to branch to main program.
mbed_official 76:aeb1df146756 32 *
mbed_official 76:aeb1df146756 33 * 3. If the system clock source selected by user fails to startup, the SystemInit()
mbed_official 76:aeb1df146756 34 * function will do nothing and MSI still used as system clock source. User can
mbed_official 76:aeb1df146756 35 * add some code to deal with this issue inside the SetSysClock() function.
mbed_official 76:aeb1df146756 36 *
mbed_official 76:aeb1df146756 37 * 4. The default value of HSE crystal is set to 8MHz, refer to "HSE_VALUE" define
mbed_official 76:aeb1df146756 38 * in "stm32l1xx.h" file. When HSE is used as system clock source, directly or
mbed_official 76:aeb1df146756 39 * through PLL, and you are using different crystal you have to adapt the HSE
mbed_official 76:aeb1df146756 40 * value to your own configuration.
mbed_official 76:aeb1df146756 41 *
mbed_official 76:aeb1df146756 42 * 5. This file configures the system clock as follows:
mbed_official 76:aeb1df146756 43 *=============================================================================
mbed_official 76:aeb1df146756 44 * System Clock Configuration
mbed_official 76:aeb1df146756 45 *=============================================================================
mbed_official 76:aeb1df146756 46 * System clock source | HSI
mbed_official 76:aeb1df146756 47 *-----------------------------------------------------------------------------
mbed_official 76:aeb1df146756 48 * SYSCLK | 16000000 Hz
mbed_official 76:aeb1df146756 49 *-----------------------------------------------------------------------------
mbed_official 76:aeb1df146756 50 * HCLK | 16000000 Hz
mbed_official 76:aeb1df146756 51 *-----------------------------------------------------------------------------
mbed_official 76:aeb1df146756 52 * AHB Prescaler | 1
mbed_official 76:aeb1df146756 53 *-----------------------------------------------------------------------------
mbed_official 76:aeb1df146756 54 * APB1 Prescaler | 1
mbed_official 76:aeb1df146756 55 *-----------------------------------------------------------------------------
mbed_official 76:aeb1df146756 56 * APB2 Prescaler | 1
mbed_official 76:aeb1df146756 57 *-----------------------------------------------------------------------------
mbed_official 76:aeb1df146756 58 * HSE Frequency | 8000000 Hz
mbed_official 76:aeb1df146756 59 *-----------------------------------------------------------------------------
mbed_official 76:aeb1df146756 60 * PLL DIV | Not Used
mbed_official 76:aeb1df146756 61 *-----------------------------------------------------------------------------
mbed_official 76:aeb1df146756 62 * PLL MUL | Not Used
mbed_official 76:aeb1df146756 63 *-----------------------------------------------------------------------------
mbed_official 76:aeb1df146756 64 * VDD | 3.3 V
mbed_official 76:aeb1df146756 65 *-----------------------------------------------------------------------------
mbed_official 76:aeb1df146756 66 * Vcore | 1.8 V (Range 1)
mbed_official 76:aeb1df146756 67 *-----------------------------------------------------------------------------
mbed_official 76:aeb1df146756 68 * Flash Latency | 0 WS
mbed_official 76:aeb1df146756 69 *-----------------------------------------------------------------------------
mbed_official 76:aeb1df146756 70 * Require 48MHz for USB clock | Disabled
mbed_official 76:aeb1df146756 71 *-----------------------------------------------------------------------------
mbed_official 76:aeb1df146756 72 *=============================================================================
mbed_official 76:aeb1df146756 73 * @attention
mbed_official 76:aeb1df146756 74 *
mbed_official 106:ced8cbb51063 75 * <h2><center>&copy; COPYRIGHT(c) 2014 STMicroelectronics</center></h2>
mbed_official 76:aeb1df146756 76 *
mbed_official 106:ced8cbb51063 77 * Redistribution and use in source and binary forms, with or without modification,
mbed_official 106:ced8cbb51063 78 * are permitted provided that the following conditions are met:
mbed_official 106:ced8cbb51063 79 * 1. Redistributions of source code must retain the above copyright notice,
mbed_official 106:ced8cbb51063 80 * this list of conditions and the following disclaimer.
mbed_official 106:ced8cbb51063 81 * 2. Redistributions in binary form must reproduce the above copyright notice,
mbed_official 106:ced8cbb51063 82 * this list of conditions and the following disclaimer in the documentation
mbed_official 106:ced8cbb51063 83 * and/or other materials provided with the distribution.
mbed_official 106:ced8cbb51063 84 * 3. Neither the name of STMicroelectronics nor the names of its contributors
mbed_official 106:ced8cbb51063 85 * may be used to endorse or promote products derived from this software
mbed_official 106:ced8cbb51063 86 * without specific prior written permission.
mbed_official 76:aeb1df146756 87 *
mbed_official 106:ced8cbb51063 88 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
mbed_official 106:ced8cbb51063 89 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
mbed_official 106:ced8cbb51063 90 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
mbed_official 106:ced8cbb51063 91 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
mbed_official 106:ced8cbb51063 92 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
mbed_official 106:ced8cbb51063 93 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
mbed_official 106:ced8cbb51063 94 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
mbed_official 106:ced8cbb51063 95 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
mbed_official 106:ced8cbb51063 96 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
mbed_official 106:ced8cbb51063 97 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
mbed_official 76:aeb1df146756 98 *
mbed_official 76:aeb1df146756 99 ******************************************************************************
mbed_official 76:aeb1df146756 100 */
mbed_official 76:aeb1df146756 101
mbed_official 76:aeb1df146756 102 /** @addtogroup CMSIS
mbed_official 76:aeb1df146756 103 * @{
mbed_official 76:aeb1df146756 104 */
mbed_official 76:aeb1df146756 105
mbed_official 76:aeb1df146756 106 /** @addtogroup stm32l1xx_system
mbed_official 76:aeb1df146756 107 * @{
mbed_official 76:aeb1df146756 108 */
mbed_official 76:aeb1df146756 109
mbed_official 76:aeb1df146756 110 /** @addtogroup STM32L1xx_System_Private_Includes
mbed_official 76:aeb1df146756 111 * @{
mbed_official 76:aeb1df146756 112 */
mbed_official 76:aeb1df146756 113
mbed_official 76:aeb1df146756 114 #include "stm32l1xx.h"
mbed_official 76:aeb1df146756 115
mbed_official 76:aeb1df146756 116 /**
mbed_official 76:aeb1df146756 117 * @}
mbed_official 76:aeb1df146756 118 */
mbed_official 76:aeb1df146756 119
mbed_official 76:aeb1df146756 120 /** @addtogroup STM32L1xx_System_Private_TypesDefinitions
mbed_official 76:aeb1df146756 121 * @{
mbed_official 76:aeb1df146756 122 */
mbed_official 76:aeb1df146756 123
mbed_official 76:aeb1df146756 124 /**
mbed_official 76:aeb1df146756 125 * @}
mbed_official 76:aeb1df146756 126 */
mbed_official 76:aeb1df146756 127
mbed_official 76:aeb1df146756 128 /** @addtogroup STM32L1xx_System_Private_Defines
mbed_official 76:aeb1df146756 129 * @{
mbed_official 76:aeb1df146756 130 */
mbed_official 76:aeb1df146756 131
mbed_official 76:aeb1df146756 132 /*!< Uncomment the following line if you need to relocate your vector Table in
mbed_official 76:aeb1df146756 133 Internal SRAM. */
mbed_official 76:aeb1df146756 134 /* #define VECT_TAB_SRAM */
mbed_official 76:aeb1df146756 135 #define VECT_TAB_OFFSET 0x0 /*!< Vector Table base offset field.
mbed_official 76:aeb1df146756 136 This value must be a multiple of 0x200. */
mbed_official 76:aeb1df146756 137 /**
mbed_official 76:aeb1df146756 138 * @}
mbed_official 76:aeb1df146756 139 */
mbed_official 76:aeb1df146756 140
mbed_official 76:aeb1df146756 141 /** @addtogroup STM32L1xx_System_Private_Macros
mbed_official 76:aeb1df146756 142 * @{
mbed_official 76:aeb1df146756 143 */
mbed_official 76:aeb1df146756 144
mbed_official 76:aeb1df146756 145 /**
mbed_official 76:aeb1df146756 146 * @}
mbed_official 76:aeb1df146756 147 */
mbed_official 76:aeb1df146756 148
mbed_official 76:aeb1df146756 149 /** @addtogroup STM32L1xx_System_Private_Variables
mbed_official 76:aeb1df146756 150 * @{
mbed_official 76:aeb1df146756 151 */
mbed_official 76:aeb1df146756 152 uint32_t SystemCoreClock = 16000000;
mbed_official 76:aeb1df146756 153 __I uint8_t PLLMulTable[9] = {3, 4, 6, 8, 12, 16, 24, 32, 48};
mbed_official 76:aeb1df146756 154 __I uint8_t AHBPrescTable[16] = {0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 6, 7, 8, 9};
mbed_official 76:aeb1df146756 155
mbed_official 76:aeb1df146756 156 /**
mbed_official 76:aeb1df146756 157 * @}
mbed_official 76:aeb1df146756 158 */
mbed_official 76:aeb1df146756 159
mbed_official 76:aeb1df146756 160 /** @addtogroup STM32L1xx_System_Private_FunctionPrototypes
mbed_official 76:aeb1df146756 161 * @{
mbed_official 76:aeb1df146756 162 */
mbed_official 76:aeb1df146756 163
mbed_official 76:aeb1df146756 164 static void SetSysClock(void);
mbed_official 76:aeb1df146756 165
mbed_official 76:aeb1df146756 166 /**
mbed_official 76:aeb1df146756 167 * @}
mbed_official 76:aeb1df146756 168 */
mbed_official 76:aeb1df146756 169
mbed_official 76:aeb1df146756 170 /** @addtogroup STM32L1xx_System_Private_Functions
mbed_official 76:aeb1df146756 171 * @{
mbed_official 76:aeb1df146756 172 */
mbed_official 76:aeb1df146756 173
mbed_official 76:aeb1df146756 174 /**
mbed_official 76:aeb1df146756 175 * @brief Setup the microcontroller system.
mbed_official 76:aeb1df146756 176 * Initialize the Embedded Flash Interface, the PLL and update the
mbed_official 76:aeb1df146756 177 * SystemCoreClock variable.
mbed_official 76:aeb1df146756 178 * @param None
mbed_official 76:aeb1df146756 179 * @retval None
mbed_official 76:aeb1df146756 180 */
mbed_official 76:aeb1df146756 181 void SystemInit (void)
mbed_official 76:aeb1df146756 182 {
mbed_official 76:aeb1df146756 183 /*!< Set MSION bit */
mbed_official 76:aeb1df146756 184 RCC->CR |= (uint32_t)0x00000100;
mbed_official 76:aeb1df146756 185
mbed_official 76:aeb1df146756 186 /*!< Reset SW[1:0], HPRE[3:0], PPRE1[2:0], PPRE2[2:0], MCOSEL[2:0] and MCOPRE[2:0] bits */
mbed_official 76:aeb1df146756 187 RCC->CFGR &= (uint32_t)0x88FFC00C;
mbed_official 76:aeb1df146756 188
mbed_official 76:aeb1df146756 189 /*!< Reset HSION, HSEON, CSSON and PLLON bits */
mbed_official 76:aeb1df146756 190 RCC->CR &= (uint32_t)0xEEFEFFFE;
mbed_official 76:aeb1df146756 191
mbed_official 76:aeb1df146756 192 /*!< Reset HSEBYP bit */
mbed_official 76:aeb1df146756 193 RCC->CR &= (uint32_t)0xFFFBFFFF;
mbed_official 76:aeb1df146756 194
mbed_official 76:aeb1df146756 195 /*!< Reset PLLSRC, PLLMUL[3:0] and PLLDIV[1:0] bits */
mbed_official 76:aeb1df146756 196 RCC->CFGR &= (uint32_t)0xFF02FFFF;
mbed_official 76:aeb1df146756 197
mbed_official 76:aeb1df146756 198 /*!< Disable all interrupts */
mbed_official 76:aeb1df146756 199 RCC->CIR = 0x00000000;
mbed_official 76:aeb1df146756 200
mbed_official 76:aeb1df146756 201 /* Configure the System clock frequency, AHB/APBx prescalers and Flash settings */
mbed_official 76:aeb1df146756 202 SetSysClock();
mbed_official 76:aeb1df146756 203
mbed_official 76:aeb1df146756 204 #ifdef VECT_TAB_SRAM
mbed_official 76:aeb1df146756 205 SCB->VTOR = SRAM_BASE | VECT_TAB_OFFSET; /* Vector Table Relocation in Internal SRAM. */
mbed_official 76:aeb1df146756 206 #else
mbed_official 76:aeb1df146756 207 SCB->VTOR = FLASH_BASE | VECT_TAB_OFFSET; /* Vector Table Relocation in Internal FLASH. */
mbed_official 76:aeb1df146756 208 #endif
mbed_official 76:aeb1df146756 209 }
mbed_official 76:aeb1df146756 210
mbed_official 76:aeb1df146756 211 /**
mbed_official 76:aeb1df146756 212 * @brief Update SystemCoreClock according to Clock Register Values
mbed_official 76:aeb1df146756 213 * The SystemCoreClock variable contains the core clock (HCLK), it can
mbed_official 76:aeb1df146756 214 * be used by the user application to setup the SysTick timer or configure
mbed_official 76:aeb1df146756 215 * other parameters.
mbed_official 76:aeb1df146756 216 *
mbed_official 76:aeb1df146756 217 * @note Each time the core clock (HCLK) changes, this function must be called
mbed_official 76:aeb1df146756 218 * to update SystemCoreClock variable value. Otherwise, any configuration
mbed_official 76:aeb1df146756 219 * based on this variable will be incorrect.
mbed_official 76:aeb1df146756 220 *
mbed_official 76:aeb1df146756 221 * @note - The system frequency computed by this function is not the real
mbed_official 76:aeb1df146756 222 * frequency in the chip. It is calculated based on the predefined
mbed_official 76:aeb1df146756 223 * constant and the selected clock source:
mbed_official 76:aeb1df146756 224 *
mbed_official 76:aeb1df146756 225 * - If SYSCLK source is MSI, SystemCoreClock will contain the MSI
mbed_official 76:aeb1df146756 226 * value as defined by the MSI range.
mbed_official 76:aeb1df146756 227 *
mbed_official 76:aeb1df146756 228 * - If SYSCLK source is HSI, SystemCoreClock will contain the HSI_VALUE(*)
mbed_official 76:aeb1df146756 229 *
mbed_official 76:aeb1df146756 230 * - If SYSCLK source is HSE, SystemCoreClock will contain the HSE_VALUE(**)
mbed_official 76:aeb1df146756 231 *
mbed_official 76:aeb1df146756 232 * - If SYSCLK source is PLL, SystemCoreClock will contain the HSE_VALUE(**)
mbed_official 76:aeb1df146756 233 * or HSI_VALUE(*) multiplied/divided by the PLL factors.
mbed_official 76:aeb1df146756 234 *
mbed_official 76:aeb1df146756 235 * (*) HSI_VALUE is a constant defined in stm32l1xx.h file (default value
mbed_official 76:aeb1df146756 236 * 16 MHz) but the real value may vary depending on the variations
mbed_official 76:aeb1df146756 237 * in voltage and temperature.
mbed_official 76:aeb1df146756 238 *
mbed_official 76:aeb1df146756 239 * (**) HSE_VALUE is a constant defined in stm32l1xx.h file (default value
mbed_official 76:aeb1df146756 240 * 8 MHz), user has to ensure that HSE_VALUE is same as the real
mbed_official 76:aeb1df146756 241 * frequency of the crystal used. Otherwise, this function may
mbed_official 76:aeb1df146756 242 * have wrong result.
mbed_official 76:aeb1df146756 243 *
mbed_official 76:aeb1df146756 244 * - The result of this function could be not correct when using fractional
mbed_official 76:aeb1df146756 245 * value for HSE crystal.
mbed_official 76:aeb1df146756 246 * @param None
mbed_official 76:aeb1df146756 247 * @retval None
mbed_official 76:aeb1df146756 248 */
mbed_official 76:aeb1df146756 249 void SystemCoreClockUpdate (void)
mbed_official 76:aeb1df146756 250 {
mbed_official 76:aeb1df146756 251 uint32_t tmp = 0, pllmul = 0, plldiv = 0, pllsource = 0, msirange = 0;
mbed_official 76:aeb1df146756 252
mbed_official 76:aeb1df146756 253 /* Get SYSCLK source -------------------------------------------------------*/
mbed_official 76:aeb1df146756 254 tmp = RCC->CFGR & RCC_CFGR_SWS;
mbed_official 76:aeb1df146756 255
mbed_official 76:aeb1df146756 256 switch (tmp)
mbed_official 76:aeb1df146756 257 {
mbed_official 76:aeb1df146756 258 case 0x00: /* MSI used as system clock */
mbed_official 76:aeb1df146756 259 msirange = (RCC->ICSCR & RCC_ICSCR_MSIRANGE) >> 13;
mbed_official 76:aeb1df146756 260 SystemCoreClock = (32768 * (1 << (msirange + 1)));
mbed_official 76:aeb1df146756 261 break;
mbed_official 76:aeb1df146756 262 case 0x04: /* HSI used as system clock */
mbed_official 76:aeb1df146756 263 SystemCoreClock = HSI_VALUE;
mbed_official 76:aeb1df146756 264 break;
mbed_official 76:aeb1df146756 265 case 0x08: /* HSE used as system clock */
mbed_official 76:aeb1df146756 266 SystemCoreClock = HSE_VALUE;
mbed_official 76:aeb1df146756 267 break;
mbed_official 76:aeb1df146756 268 case 0x0C: /* PLL used as system clock */
mbed_official 76:aeb1df146756 269 /* Get PLL clock source and multiplication factor ----------------------*/
mbed_official 76:aeb1df146756 270 pllmul = RCC->CFGR & RCC_CFGR_PLLMUL;
mbed_official 76:aeb1df146756 271 plldiv = RCC->CFGR & RCC_CFGR_PLLDIV;
mbed_official 76:aeb1df146756 272 pllmul = PLLMulTable[(pllmul >> 18)];
mbed_official 76:aeb1df146756 273 plldiv = (plldiv >> 22) + 1;
mbed_official 76:aeb1df146756 274
mbed_official 76:aeb1df146756 275 pllsource = RCC->CFGR & RCC_CFGR_PLLSRC;
mbed_official 76:aeb1df146756 276
mbed_official 76:aeb1df146756 277 if (pllsource == 0x00)
mbed_official 76:aeb1df146756 278 {
mbed_official 76:aeb1df146756 279 /* HSI oscillator clock selected as PLL clock entry */
mbed_official 76:aeb1df146756 280 SystemCoreClock = (((HSI_VALUE) * pllmul) / plldiv);
mbed_official 76:aeb1df146756 281 }
mbed_official 76:aeb1df146756 282 else
mbed_official 76:aeb1df146756 283 {
mbed_official 76:aeb1df146756 284 /* HSE selected as PLL clock entry */
mbed_official 76:aeb1df146756 285 SystemCoreClock = (((HSE_VALUE) * pllmul) / plldiv);
mbed_official 76:aeb1df146756 286 }
mbed_official 76:aeb1df146756 287 break;
mbed_official 76:aeb1df146756 288 default: /* MSI used as system clock */
mbed_official 76:aeb1df146756 289 msirange = (RCC->ICSCR & RCC_ICSCR_MSIRANGE) >> 13;
mbed_official 76:aeb1df146756 290 SystemCoreClock = (32768 * (1 << (msirange + 1)));
mbed_official 76:aeb1df146756 291 break;
mbed_official 76:aeb1df146756 292 }
mbed_official 76:aeb1df146756 293 /* Compute HCLK clock frequency --------------------------------------------*/
mbed_official 76:aeb1df146756 294 /* Get HCLK prescaler */
mbed_official 76:aeb1df146756 295 tmp = AHBPrescTable[((RCC->CFGR & RCC_CFGR_HPRE) >> 4)];
mbed_official 76:aeb1df146756 296 /* HCLK clock frequency */
mbed_official 76:aeb1df146756 297 SystemCoreClock >>= tmp;
mbed_official 76:aeb1df146756 298 }
mbed_official 76:aeb1df146756 299
mbed_official 76:aeb1df146756 300 /**
mbed_official 76:aeb1df146756 301 * @brief Configures the System clock frequency, AHB/APBx prescalers and Flash
mbed_official 76:aeb1df146756 302 * settings.
mbed_official 76:aeb1df146756 303 * @note This function should be called only once the RCC clock configuration
mbed_official 76:aeb1df146756 304 * is reset to the default reset state (done in SystemInit() function).
mbed_official 76:aeb1df146756 305 * @param None
mbed_official 76:aeb1df146756 306 * @retval None
mbed_official 76:aeb1df146756 307 */
mbed_official 76:aeb1df146756 308 static void SetSysClock(void)
mbed_official 76:aeb1df146756 309 {
mbed_official 76:aeb1df146756 310 __IO uint32_t StartUpCounter = 0, HSIStatus = 0;
mbed_official 76:aeb1df146756 311
mbed_official 76:aeb1df146756 312 /* SYSCLK, HCLK, PCLK2 and PCLK1 configuration ---------------------------*/
mbed_official 76:aeb1df146756 313 /* Enable HSI */
mbed_official 76:aeb1df146756 314 RCC->CR |= ((uint32_t)RCC_CR_HSION);
mbed_official 76:aeb1df146756 315
mbed_official 76:aeb1df146756 316 /* Wait till HSI is ready and if Time out is reached exit */
mbed_official 76:aeb1df146756 317 do
mbed_official 76:aeb1df146756 318 {
mbed_official 76:aeb1df146756 319 HSIStatus = RCC->CR & RCC_CR_HSIRDY;
mbed_official 76:aeb1df146756 320 } while((HSIStatus == 0) && (StartUpCounter != HSI_STARTUP_TIMEOUT));
mbed_official 76:aeb1df146756 321
mbed_official 76:aeb1df146756 322 if ((RCC->CR & RCC_CR_HSIRDY) != RESET)
mbed_official 76:aeb1df146756 323 {
mbed_official 76:aeb1df146756 324 HSIStatus = (uint32_t)0x01;
mbed_official 76:aeb1df146756 325 }
mbed_official 76:aeb1df146756 326 else
mbed_official 76:aeb1df146756 327 {
mbed_official 76:aeb1df146756 328 HSIStatus = (uint32_t)0x00;
mbed_official 76:aeb1df146756 329 }
mbed_official 76:aeb1df146756 330
mbed_official 76:aeb1df146756 331 if (HSIStatus == (uint32_t)0x01)
mbed_official 76:aeb1df146756 332 {
mbed_official 76:aeb1df146756 333 /* Flash 0 wait state */
mbed_official 76:aeb1df146756 334 FLASH->ACR &= ~FLASH_ACR_LATENCY;
mbed_official 76:aeb1df146756 335
mbed_official 76:aeb1df146756 336 /* Disable Prefetch Buffer */
mbed_official 76:aeb1df146756 337 FLASH->ACR &= ~FLASH_ACR_PRFTEN;
mbed_official 76:aeb1df146756 338
mbed_official 76:aeb1df146756 339 /* Disable 64-bit access */
mbed_official 76:aeb1df146756 340 FLASH->ACR &= ~FLASH_ACR_ACC64;
mbed_official 76:aeb1df146756 341
mbed_official 76:aeb1df146756 342
mbed_official 76:aeb1df146756 343 /* Power enable */
mbed_official 76:aeb1df146756 344 RCC->APB1ENR |= RCC_APB1ENR_PWREN;
mbed_official 76:aeb1df146756 345
mbed_official 76:aeb1df146756 346 /* Select the Voltage Range 1 (1.8 V) */
mbed_official 76:aeb1df146756 347 PWR->CR = PWR_CR_VOS_0;
mbed_official 76:aeb1df146756 348
mbed_official 76:aeb1df146756 349
mbed_official 76:aeb1df146756 350 /* Wait Until the Voltage Regulator is ready */
mbed_official 76:aeb1df146756 351 while((PWR->CSR & PWR_CSR_VOSF) != RESET)
mbed_official 76:aeb1df146756 352 {
mbed_official 76:aeb1df146756 353 }
mbed_official 76:aeb1df146756 354
mbed_official 76:aeb1df146756 355 /* HCLK = SYSCLK /1*/
mbed_official 76:aeb1df146756 356 RCC->CFGR |= (uint32_t)RCC_CFGR_HPRE_DIV1;
mbed_official 76:aeb1df146756 357 /* PCLK2 = HCLK /1*/
mbed_official 76:aeb1df146756 358 RCC->CFGR |= (uint32_t)RCC_CFGR_PPRE2_DIV1;
mbed_official 76:aeb1df146756 359
mbed_official 76:aeb1df146756 360 /* PCLK1 = HCLK /1*/
mbed_official 76:aeb1df146756 361 RCC->CFGR |= (uint32_t)RCC_CFGR_PPRE1_DIV1;
mbed_official 76:aeb1df146756 362
mbed_official 76:aeb1df146756 363 /* Select HSI as system clock source */
mbed_official 76:aeb1df146756 364 RCC->CFGR &= (uint32_t)((uint32_t)~(RCC_CFGR_SW));
mbed_official 76:aeb1df146756 365 RCC->CFGR |= (uint32_t)RCC_CFGR_SW_HSI;
mbed_official 76:aeb1df146756 366
mbed_official 76:aeb1df146756 367 /* Wait till HSI is used as system clock source */
mbed_official 76:aeb1df146756 368 while ((RCC->CFGR & (uint32_t)RCC_CFGR_SWS) != (uint32_t)RCC_CFGR_SWS_HSI)
mbed_official 76:aeb1df146756 369 {
mbed_official 76:aeb1df146756 370 }
mbed_official 76:aeb1df146756 371 }
mbed_official 76:aeb1df146756 372 else
mbed_official 76:aeb1df146756 373 {
mbed_official 76:aeb1df146756 374 /* If HSI fails to start-up, the application will have wrong clock
mbed_official 76:aeb1df146756 375 configuration. User can add here some code to deal with this error */
mbed_official 76:aeb1df146756 376 }
mbed_official 76:aeb1df146756 377 }
mbed_official 76:aeb1df146756 378
mbed_official 76:aeb1df146756 379 /**
mbed_official 76:aeb1df146756 380 * @}
mbed_official 76:aeb1df146756 381 */
mbed_official 76:aeb1df146756 382
mbed_official 76:aeb1df146756 383 /**
mbed_official 76:aeb1df146756 384 * @}
mbed_official 76:aeb1df146756 385 */
mbed_official 76:aeb1df146756 386
mbed_official 76:aeb1df146756 387 /**
mbed_official 76:aeb1df146756 388 * @}
mbed_official 76:aeb1df146756 389 */
mbed_official 76:aeb1df146756 390
mbed_official 76:aeb1df146756 391 /******************* (C) COPYRIGHT 2013 STMicroelectronics *****END OF FILE****/