mbed library sources modified for open wear
Dependents: openwear-lifelogger-example
Fork of mbed-src by
targets/cmsis/TARGET_STM/TARGET_DISCO_F051R8/system_stm32f0xx.c
- Committer:
- janekm
- Date:
- 2014-09-16
- Revision:
- 310:6188e0254baa
- Parent:
- 240:9a7c54113eaf
File content as of revision 310:6188e0254baa:
/** ****************************************************************************** * @file system_stm32f0xx.c * @author MCD Application Team * @version V1.0.1 * @date 12-January-2014 * @brief CMSIS Cortex-M0 Device Peripheral Access Layer System Source File. * This file contains the system clock configuration for STM32F0xx devices, * and is generated by the clock configuration tool * STM32F0xx_Clock_Configuration_V1.0.1.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_stm32f0xx.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 HSI (8 MHz Range) is used as system clock source. * Then SystemInit() function is called, in "startup_stm32f0xx.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 HSI 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 "stm32f0xx.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 8 MHz) * | 2- PLL_HSE_XTAL | * | (external 8 MHz xtal) | *----------------------------------------------------------------------------- * SYSCLK(MHz) | 48 | 48 *----------------------------------------------------------------------------- * AHBCLK (MHz) | 48 | 48 *----------------------------------------------------------------------------- * APBCLK (MHz) | 48 | 48 *----------------------------------------------------------------------------- ****************************************************************************** * @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 stm32f0xx_system * @{ */ /** @addtogroup STM32F0xx_System_Private_Includes * @{ */ #include "stm32f0xx.h" /** * @} */ /** @addtogroup STM32F0xx_System_Private_TypesDefinitions * @{ */ /** * @} */ /** @addtogroup STM32F0xx_System_Private_Defines * @{ */ /** * @} */ /** @addtogroup STM32F0xx_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 STM32F0xx_System_Private_Variables * @{ */ uint32_t SystemCoreClock = 48000000; __I uint8_t AHBPrescTable[16] = {0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 6, 7, 8, 9}; /** * @} */ /** @addtogroup STM32F0xx_System_Private_FunctionPrototypes * @{ */ #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 STM32F0xx_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 HSION bit */ RCC->CR |= (uint32_t)0x00000001; /* Reset SW[1:0], HPRE[3:0], PPRE[2:0], ADCPRE and MCOSEL[2:0] bits */ RCC->CFGR &= (uint32_t)0xF8FFB80C; /* Reset HSEON, CSSON and PLLON bits */ RCC->CR &= (uint32_t)0xFEF6FFFF; /* Reset HSEBYP bit */ RCC->CR &= (uint32_t)0xFFFBFFFF; /* Reset PLLSRC, PLLXTPRE and PLLMUL[3:0] bits */ RCC->CFGR &= (uint32_t)0xFFC0FFFF; /* Reset PREDIV1[3:0] bits */ RCC->CFGR2 &= (uint32_t)0xFFFFFFF0; /* Reset USARTSW[1:0], I2CSW, CECSW and ADCSW bits */ RCC->CFGR3 &= (uint32_t)0xFFFFFEAC; /* Reset HSI14 bit */ RCC->CR2 &= (uint32_t)0xFFFFFFFE; /* Disable all interrupts */ RCC->CIR = 0x00000000; /* Configure the System clock source, PLL Multiplier and Divider factors, AHB/APBx prescalers and Flash settings */ SetSysClock(); } /** * @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 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 stm32f0xx.h file (default value * 8 MHz) but the real value may vary depending on the variations * in voltage and temperature. * * (**) HSE_VALUE is a constant defined in stm32f0xx.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, pllmull = 0, pllsource = 0, prediv1factor = 0; /* Get SYSCLK source -------------------------------------------------------*/ tmp = RCC->CFGR & RCC_CFGR_SWS; switch (tmp) { case 0x00: /* HSI used as system clock */ SystemCoreClock = HSI_VALUE; break; case 0x04: /* HSE used as system clock */ SystemCoreClock = HSE_VALUE; break; case 0x08: /* PLL used as system clock */ /* Get PLL clock source and multiplication factor ----------------------*/ pllmull = RCC->CFGR & RCC_CFGR_PLLMULL; pllsource = RCC->CFGR & RCC_CFGR_PLLSRC; pllmull = ( pllmull >> 18) + 2; if (pllsource == 0x00) { /* HSI oscillator clock divided by 2 selected as PLL clock entry */ SystemCoreClock = (HSI_VALUE >> 1) * pllmull; } else { prediv1factor = (RCC->CFGR2 & RCC_CFGR2_PREDIV1) + 1; /* HSE oscillator clock selected as PREDIV1 clock entry */ SystemCoreClock = (HSE_VALUE / prediv1factor) * pllmull; } break; default: /* HSI used as system clock */ SystemCoreClock = HSI_VALUE; 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, HCLK, PCLK2 and PCLK1 prescalers. * @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 clock on MCO pin (PA8) for debugging purpose /* RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA, ENABLE); GPIO_InitTypeDef GPIO_InitStructure; GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF; GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; GPIO_InitStructure.GPIO_OType = GPIO_OType_PP; GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP; GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8; GPIO_Init(GPIOA, &GPIO_InitStructure); GPIO_PinAFConfig(GPIOA, GPIO_PinSource8, GPIO_AF_0); // Output clock on MCO pin // Warning: only RCC_MCOPrescaler_1 is available on STM32F030x8 devices RCC_MCOConfig(RCC_MCOSource_SYSCLK, RCC_MCOPrescaler_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 Prefetch Buffer */ FLASH->ACR |= FLASH_ACR_PRFTBE; /* Enable Prefetch Buffer and set Flash Latency */ FLASH->ACR = FLASH_ACR_PRFTBE | FLASH_ACR_LATENCY; /* PLL configuration PLLCLK = 48 MHz (xtal 8 MHz * 6) */ RCC->CFGR &= (uint32_t)((uint32_t)~(RCC_CFGR_PLLSRC | RCC_CFGR_PLLXTPRE | RCC_CFGR_PLLMULL)); RCC->CFGR |= (uint32_t)(RCC_CFGR_PLLSRC_PREDIV1 | RCC_CFGR_PLLXTPRE_PREDIV1 | RCC_CFGR_PLLMULL6 | RCC_CFGR_HPRE_DIV1 /* HCLK = 48 MHz */ | RCC_CFGR_PPRE_DIV1); /* PCLK = 48 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) { /* Enable Prefetch Buffer and set Flash Latency */ FLASH->ACR = FLASH_ACR_PRFTBE | FLASH_ACR_LATENCY; /* PLL configuration PLLCLK = 48 MHz ((HSI 8 MHz / 2) * 12) */ RCC->CFGR &= (uint32_t)((uint32_t)~(RCC_CFGR_PLLSRC | RCC_CFGR_PLLXTPRE | RCC_CFGR_PLLMULL)); RCC->CFGR |= (uint32_t)(RCC_CFGR_PLLSRC_HSI_Div2 | RCC_CFGR_PLLXTPRE_PREDIV1 | RCC_CFGR_PLLMULL12 | RCC_CFGR_HPRE_DIV1 /* HCLK = 48 MHz */ | RCC_CFGR_PPRE_DIV1); /* PCLK = 48 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 } /** * @} */ /** * @} */ /** * @} */ /************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/