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Diff: targets/cmsis/TARGET_STM/TARGET_NUCLEO_L152RE/system_stm32l1xx.c
- Revision:
- 76:aeb1df146756
- Child:
- 106:ced8cbb51063
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/targets/cmsis/TARGET_STM/TARGET_NUCLEO_L152RE/system_stm32l1xx.c Mon Jan 27 14:30:07 2014 +0000
@@ -0,0 +1,381 @@
+/**
+ ******************************************************************************
+ * @file system_stm32l1xx.c
+ * @author MCD Application Team
+ * @version V1.2.0
+ * @date 11-January-2014
+ * @brief CMSIS Cortex-M3 Device Peripheral Access Layer System Source File.
+ * This file contains the system clock configuration for STM32L1xx Ultra
+ * Low power devices, and is generated by the clock configuration
+ * tool STM32L1xx_Clock_Configuration_V1.2.0.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_stm32l1xx_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 MSI (2.1 MHz Range) is used as system clock source.
+ * Then SystemInit() function is called, in "startup_stm32l1xx_xx.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 MSI 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 "stm32l1xx.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:
+ *=============================================================================
+ * System Clock Configuration
+ *=============================================================================
+ * System clock source | HSI
+ *-----------------------------------------------------------------------------
+ * SYSCLK | 16000000 Hz
+ *-----------------------------------------------------------------------------
+ * HCLK | 16000000 Hz
+ *-----------------------------------------------------------------------------
+ * AHB Prescaler | 1
+ *-----------------------------------------------------------------------------
+ * APB1 Prescaler | 1
+ *-----------------------------------------------------------------------------
+ * APB2 Prescaler | 1
+ *-----------------------------------------------------------------------------
+ * HSE Frequency | 8000000 Hz
+ *-----------------------------------------------------------------------------
+ * PLL DIV | Not Used
+ *-----------------------------------------------------------------------------
+ * PLL MUL | Not Used
+ *-----------------------------------------------------------------------------
+ * VDD | 3.3 V
+ *-----------------------------------------------------------------------------
+ * Vcore | 1.8 V (Range 1)
+ *-----------------------------------------------------------------------------
+ * Flash Latency | 0 WS
+ *-----------------------------------------------------------------------------
+ * Require 48MHz for USB clock | Disabled
+ *-----------------------------------------------------------------------------
+ *=============================================================================
+ * @attention
+ *
+ * <h2><center>© COPYRIGHT 2013 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 stm32l1xx_system
+ * @{
+ */
+
+/** @addtogroup STM32L1xx_System_Private_Includes
+ * @{
+ */
+
+#include "stm32l1xx.h"
+
+/**
+ * @}
+ */
+
+/** @addtogroup STM32L1xx_System_Private_TypesDefinitions
+ * @{
+ */
+
+/**
+ * @}
+ */
+
+/** @addtogroup STM32L1xx_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 STM32L1xx_System_Private_Macros
+ * @{
+ */
+
+/**
+ * @}
+ */
+
+/** @addtogroup STM32L1xx_System_Private_Variables
+ * @{
+ */
+uint32_t SystemCoreClock = 16000000;
+__I uint8_t PLLMulTable[9] = {3, 4, 6, 8, 12, 16, 24, 32, 48};
+__I uint8_t AHBPrescTable[16] = {0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 6, 7, 8, 9};
+
+/**
+ * @}
+ */
+
+/** @addtogroup STM32L1xx_System_Private_FunctionPrototypes
+ * @{
+ */
+
+static void SetSysClock(void);
+
+/**
+ * @}
+ */
+
+/** @addtogroup STM32L1xx_System_Private_Functions
+ * @{
+ */
+
+/**
+ * @brief Setup the microcontroller system.
+ * Initialize the Embedded Flash Interface, the PLL and update the
+ * SystemCoreClock variable.
+ * @param None
+ * @retval None
+ */
+void SystemInit (void)
+{
+ /*!< Set MSION bit */
+ RCC->CR |= (uint32_t)0x00000100;
+
+ /*!< Reset SW[1:0], HPRE[3:0], PPRE1[2:0], PPRE2[2:0], MCOSEL[2:0] and MCOPRE[2:0] bits */
+ RCC->CFGR &= (uint32_t)0x88FFC00C;
+
+ /*!< Reset HSION, HSEON, CSSON and PLLON bits */
+ RCC->CR &= (uint32_t)0xEEFEFFFE;
+
+ /*!< Reset HSEBYP bit */
+ RCC->CR &= (uint32_t)0xFFFBFFFF;
+
+ /*!< Reset PLLSRC, PLLMUL[3:0] and PLLDIV[1:0] bits */
+ RCC->CFGR &= (uint32_t)0xFF02FFFF;
+
+ /*!< Disable all interrupts */
+ RCC->CIR = 0x00000000;
+
+ /* Configure the System clock frequency, 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 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 MSI, SystemCoreClock will contain the MSI
+ * value as defined by the MSI range.
+ *
+ * - 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 stm32l1xx.h file (default value
+ * 16 MHz) but the real value may vary depending on the variations
+ * in voltage and temperature.
+ *
+ * (**) HSE_VALUE is a constant defined in stm32l1xx.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, pllmul = 0, plldiv = 0, pllsource = 0, msirange = 0;
+
+ /* Get SYSCLK source -------------------------------------------------------*/
+ tmp = RCC->CFGR & RCC_CFGR_SWS;
+
+ switch (tmp)
+ {
+ case 0x00: /* MSI used as system clock */
+ msirange = (RCC->ICSCR & RCC_ICSCR_MSIRANGE) >> 13;
+ SystemCoreClock = (32768 * (1 << (msirange + 1)));
+ break;
+ case 0x04: /* HSI used as system clock */
+ SystemCoreClock = HSI_VALUE;
+ break;
+ case 0x08: /* HSE used as system clock */
+ SystemCoreClock = HSE_VALUE;
+ break;
+ case 0x0C: /* PLL used as system clock */
+ /* Get PLL clock source and multiplication factor ----------------------*/
+ pllmul = RCC->CFGR & RCC_CFGR_PLLMUL;
+ plldiv = RCC->CFGR & RCC_CFGR_PLLDIV;
+ pllmul = PLLMulTable[(pllmul >> 18)];
+ plldiv = (plldiv >> 22) + 1;
+
+ pllsource = RCC->CFGR & RCC_CFGR_PLLSRC;
+
+ if (pllsource == 0x00)
+ {
+ /* HSI oscillator clock selected as PLL clock entry */
+ SystemCoreClock = (((HSI_VALUE) * pllmul) / plldiv);
+ }
+ else
+ {
+ /* HSE selected as PLL clock entry */
+ SystemCoreClock = (((HSE_VALUE) * pllmul) / plldiv);
+ }
+ break;
+ default: /* MSI used as system clock */
+ msirange = (RCC->ICSCR & RCC_ICSCR_MSIRANGE) >> 13;
+ SystemCoreClock = (32768 * (1 << (msirange + 1)));
+ 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 frequency, 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, HSIStatus = 0;
+
+ /* SYSCLK, HCLK, PCLK2 and PCLK1 configuration ---------------------------*/
+ /* Enable HSI */
+ RCC->CR |= ((uint32_t)RCC_CR_HSION);
+
+ /* Wait till HSI is ready and if Time out is reached exit */
+ do
+ {
+ HSIStatus = RCC->CR & RCC_CR_HSIRDY;
+ } while((HSIStatus == 0) && (StartUpCounter != HSI_STARTUP_TIMEOUT));
+
+ if ((RCC->CR & RCC_CR_HSIRDY) != RESET)
+ {
+ HSIStatus = (uint32_t)0x01;
+ }
+ else
+ {
+ HSIStatus = (uint32_t)0x00;
+ }
+
+ if (HSIStatus == (uint32_t)0x01)
+ {
+ /* Flash 0 wait state */
+ FLASH->ACR &= ~FLASH_ACR_LATENCY;
+
+ /* Disable Prefetch Buffer */
+ FLASH->ACR &= ~FLASH_ACR_PRFTEN;
+
+ /* Disable 64-bit access */
+ FLASH->ACR &= ~FLASH_ACR_ACC64;
+
+
+ /* Power enable */
+ RCC->APB1ENR |= RCC_APB1ENR_PWREN;
+
+ /* Select the Voltage Range 1 (1.8 V) */
+ PWR->CR = PWR_CR_VOS_0;
+
+
+ /* Wait Until the Voltage Regulator is ready */
+ while((PWR->CSR & PWR_CSR_VOSF) != RESET)
+ {
+ }
+
+ /* HCLK = SYSCLK /1*/
+ RCC->CFGR |= (uint32_t)RCC_CFGR_HPRE_DIV1;
+ /* PCLK2 = HCLK /1*/
+ RCC->CFGR |= (uint32_t)RCC_CFGR_PPRE2_DIV1;
+
+ /* PCLK1 = HCLK /1*/
+ RCC->CFGR |= (uint32_t)RCC_CFGR_PPRE1_DIV1;
+
+ /* Select HSI as system clock source */
+ RCC->CFGR &= (uint32_t)((uint32_t)~(RCC_CFGR_SW));
+ RCC->CFGR |= (uint32_t)RCC_CFGR_SW_HSI;
+
+ /* Wait till HSI is used as system clock source */
+ while ((RCC->CFGR & (uint32_t)RCC_CFGR_SWS) != (uint32_t)RCC_CFGR_SWS_HSI)
+ {
+ }
+ }
+ else
+ {
+ /* If HSI fails to start-up, the application will have wrong clock
+ configuration. User can add here some code to deal with this error */
+ }
+}
+
+/**
+ * @}
+ */
+
+/**
+ * @}
+ */
+
+/**
+ * @}
+ */
+
+/******************* (C) COPYRIGHT 2013 STMicroelectronics *****END OF FILE****/