mbed library sources
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targets/cmsis/TARGET_STM/TARGET_NUCLEO_L152RE/system_stm32l1xx.c
- Committer:
- mbed_official
- Date:
- 2014-03-27
- Revision:
- 139:e3413eddde57
- Parent:
- 129:0182c99221bc
- Child:
- 354:e67efb2aab0e
File content as of revision 139:e3413eddde57:
/** ****************************************************************************** * @file system_stm32l1xx.c * @author MCD Application Team * @version V1.2.0 * @date 14-March-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 source | 1- PLL_HSE_EXTC | 3- PLL_HSI * | (external 8 MHz clock) | (internal 16 MHz) * | 2- PLL_HSE_XTAL | * | (external 8 MHz xtal) | *----------------------------------------------------------------------------- * SYSCLK(MHz) | 24 | 32 *----------------------------------------------------------------------------- * AHBCLK (MHz) | 24 | 32 *----------------------------------------------------------------------------- * APB1CLK (MHz) | 24 | 32 *----------------------------------------------------------------------------- * APB2CLK (MHz) | 24 | 32 *----------------------------------------------------------------------------- * USB capable (48 MHz precise clock) | YES | NO *----------------------------------------------------------------------------- ****************************************************************************** * @attention * * <h2><center>© COPYRIGHT(c) 2014 STMicroelectronics</center></h2> * * Redistribution and use in source and binary forms, with or without modification, * are permitted provided that the following conditions are met: * 1. Redistributions of source code must retain the above copyright notice, * this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright notice, * this list of conditions and the following disclaimer in the documentation * and/or other materials provided with the distribution. * 3. Neither the name of STMicroelectronics nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. * ****************************************************************************** */ /** @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 * @{ */ /* Select the clock sources (other than HSI) to start with (0=OFF, 1=ON) */ #define USE_PLL_HSE_EXTC (1) /* Use external clock */ #define USE_PLL_HSE_XTAL (1) /* Use external xtal */ /** * @} */ /** @addtogroup STM32L1xx_System_Private_Variables * @{ */ uint32_t SystemCoreClock = 32000000; /* Default with HSI. Will be updated if HSE is used */ __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 * @{ */ void SetSysClock(void); #if (USE_PLL_HSE_XTAL != 0) || (USE_PLL_HSE_EXTC != 0) uint8_t SetSysClock_PLL_HSE(uint8_t bypass); #endif uint8_t SetSysClock_PLL_HSI(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 source, PLL Multiplier and Divider factors, AHB/APBx prescalers and Flash settings */ SetSysClock(); /* Configure the Vector Table location add offset address ------------------*/ #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 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 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 */ void SetSysClock(void) { /* 1- Try to start with HSE and external clock */ #if USE_PLL_HSE_EXTC != 0 if (SetSysClock_PLL_HSE(1) == 0) #endif { /* 2- If fail try to start with HSE and external xtal */ #if USE_PLL_HSE_XTAL != 0 if (SetSysClock_PLL_HSE(0) == 0) #endif { /* 3- If fail start with HSI clock */ if (SetSysClock_PLL_HSI() == 0) { while(1) { // [TODO] Put something here to tell the user that a problem occured... } } } } /* Output SYSCLK on MCO pin(PA8) for debugging purpose */ /* // Enable GPIOA clock RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA, ENABLE); // Configure MCO pin (PA8) GPIO_InitTypeDef GPIO_InitStructure; GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8; GPIO_InitStructure.GPIO_Speed = GPIO_Speed_40MHz; GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF; GPIO_InitStructure.GPIO_OType = GPIO_OType_PP; GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP; GPIO_Init(GPIOA, &GPIO_InitStructure); // Select the clock to output RCC_MCOConfig(RCC_MCOSource_SYSCLK, RCC_MCODiv_1); */ } #if (USE_PLL_HSE_XTAL != 0) || (USE_PLL_HSE_EXTC != 0) /******************************************************************************/ /* PLL (clocked by HSE) used as System clock source */ /******************************************************************************/ uint8_t SetSysClock_PLL_HSE(uint8_t bypass) { __IO uint32_t StartUpCounter = 0; __IO uint32_t HSEStatus = 0; /* Bypass HSE: can be done only if HSE is OFF */ RCC->CR &= ((uint32_t)~RCC_CR_HSEON); /* To be sure HSE is OFF */ if (bypass != 0) { RCC->CR |= ((uint32_t)RCC_CR_HSEBYP); } else { RCC->CR &= ((uint32_t)~RCC_CR_HSEBYP); } /* Enable HSE */ RCC->CR |= ((uint32_t)RCC_CR_HSEON); /* Wait till HSE is ready */ do { HSEStatus = RCC->CR & RCC_CR_HSERDY; StartUpCounter++; } while((HSEStatus == 0) && (StartUpCounter != HSE_STARTUP_TIMEOUT)); /* Check if HSE has started correctly */ if ((RCC->CR & RCC_CR_HSERDY) != RESET) { /* Enable 64-bit access */ FLASH->ACR |= FLASH_ACR_ACC64; /* Enable Prefetch Buffer */ FLASH->ACR |= FLASH_ACR_PRFTEN; /* Flash 1 wait state (latency) */ FLASH->ACR |= FLASH_ACR_LATENCY; /* 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) { } /* PLL configuration */ /* SYSCLK = 24 MHz ((8 MHz * 6) / 2) */ /* USBCLK = 48 MHz (8 MHz * 6) --> USB OK */ RCC->CFGR &= (uint32_t)((uint32_t)~(RCC_CFGR_PLLSRC | RCC_CFGR_PLLMUL | RCC_CFGR_PLLDIV)); RCC->CFGR |= (uint32_t)(RCC_CFGR_PLLSRC_HSE | RCC_CFGR_PLLMUL6 | RCC_CFGR_PLLDIV2 | RCC_CFGR_HPRE_DIV1 /* HCLK = 24 MHz */ | RCC_CFGR_PPRE2_DIV1 /* PCLK2 = 24 MHz */ | RCC_CFGR_PPRE1_DIV1); /* PCLK1 = 24 MHz */ /* 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) { } return 1; // OK } else { return 0; // FAIL } } #endif /******************************************************************************/ /* PLL (clocked by HSI) used as System clock source */ /******************************************************************************/ uint8_t SetSysClock_PLL_HSI(void) { __IO uint32_t StartUpCounter = 0; __IO uint32_t HSIStatus = 0; /* Enable HSI */ RCC->CR |= ((uint32_t)RCC_CR_HSION); /* Wait till HSI is ready */ do { HSIStatus = RCC->CR & RCC_CR_HSIRDY; StartUpCounter++; } while((HSIStatus == 0) && (StartUpCounter != HSI_STARTUP_TIMEOUT)); if ((RCC->CR & RCC_CR_HSIRDY) != RESET) { /* Enable 64-bit access */ FLASH->ACR |= FLASH_ACR_ACC64; /* Enable Prefetch Buffer */ FLASH->ACR |= FLASH_ACR_PRFTEN; /* Flash 1 wait state (latency) */ FLASH->ACR |= FLASH_ACR_LATENCY; /* 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) { } /* PLL configuration */ /* SYSCLK = 32 MHz ((16 MHz * 4) / 2) */ /* USBCLK = 64 MHz (16 MHz * 4) --> USB not possible */ RCC->CFGR &= (uint32_t)((uint32_t)~(RCC_CFGR_PLLSRC | RCC_CFGR_PLLMUL | RCC_CFGR_PLLDIV)); RCC->CFGR |= (uint32_t)(RCC_CFGR_PLLSRC_HSI | RCC_CFGR_PLLMUL4 | RCC_CFGR_PLLDIV2 | RCC_CFGR_HPRE_DIV1 /* HCLK = 32 MHz */ | RCC_CFGR_PPRE2_DIV1 /* PCLK2 = 32 MHz */ | RCC_CFGR_PPRE1_DIV1); /* PCLK1 = 32 MHz */ /* 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) { } return 1; // OK } else { return 0; // FAIL } } /** * @} */ /** * @} */ /** * @} */ /******************* (C) COPYRIGHT 2013 STMicroelectronics *****END OF FILE****/