/**
******************************************************************************
* @file system_stm32l1xx.c
* @author MCD Application Team
* @version V1.1.1
* @date 09-March-2012
* @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_V1.1.0.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 | PLL(HSE)
*-----------------------------------------------------------------------------
* SYSCLK | 32000000 Hz
*-----------------------------------------------------------------------------
* HCLK | 32000000 Hz
*-----------------------------------------------------------------------------
* AHB Prescaler | 1
*-----------------------------------------------------------------------------
* APB1 Prescaler | 1
*-----------------------------------------------------------------------------
* APB2 Prescaler | 1
*-----------------------------------------------------------------------------
* HSE Frequency | 8000000 Hz
*-----------------------------------------------------------------------------
* PLL DIV | 3
*-----------------------------------------------------------------------------
* PLL MUL | 12
*-----------------------------------------------------------------------------
* VDD | 3.3 V
*-----------------------------------------------------------------------------
* Vcore | 1.8 V (Range 1)
*-----------------------------------------------------------------------------
* Flash Latency | 1 WS
*-----------------------------------------------------------------------------
* SDIO clock (SDIOCLK) | 48000000 Hz
*-----------------------------------------------------------------------------
* Require 48MHz for USB clock | Disabled
*-----------------------------------------------------------------------------
*=============================================================================
******************************************************************************
* @attention
*
* <h2><center>© 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 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 use external SRAM mounted
on STM32L152D_EVAL board as data memory */
/* #define DATA_IN_ExtSRAM */
/*!< 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 = 32000000;
__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);
#ifdef DATA_IN_ExtSRAM
static void SystemInit_ExtMemCtl(void);
#endif /* DATA_IN_ExtSRAM */
/**
* @}
*/
/** @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;
#ifdef DATA_IN_ExtSRAM
SystemInit_ExtMemCtl();
#endif /* DATA_IN_ExtSRAM */
/* Configure the System clock frequency, AHB/APBx prescalers and Flash settin
