RCC_UseHSEasSystemClock
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Outline
Includes
#include "main.h"
Private define
#define TIMEOUT_VALUE
Private function prototypes
main()
StartHSE()
RCC_WaitForHSEReady()
LED_Init()
LED_On()
LED_Blinking(uint32_t)
HSEReady_Callback()
HSEFailureDetection_Callback()
Files
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SourceVuSTM32 Libraries and SamplesRCC_UseHSEasSystemClockSrc/main.c
 
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/** ****************************************************************************** * @file Examples_LL/RCC/RCC_UseHSEasSystemClock/Src/main.c * @author MCD Application Team * @brief This example describes how to use the RCC LL API how to start the HSE * and use it as system clock. ****************************************************************************** * @attention * * Copyright (c) 2017 STMicroelectronics. * All rights reserved. * * This software is licensed under terms that can be found in the LICENSE file * in the root directory of this software component. * If no LICENSE file comes with this software, it is provided AS-IS. * ****************************************************************************** *//* ... */ /* Includes ------------------------------------------------------------------*/ #include "main.h" /** @addtogroup STM32F4xx_LL_Examples * @{ *//* ... */ /** @addtogroup RCC_UseHSEasSystemClock * @{ *//* ... */ Includes /* Private typedef -----------------------------------------------------------*/ /* Private define ------------------------------------------------------------*/ #if (USE_TIMEOUT == 1) #define TIMEOUT_VALUE 1000 /* Time-out set to 1 sec */ #endif /* USE_TIMEOUT */ Private define /* Private macro -------------------------------------------------------------*/ /* Private variables ---------------------------------------------------------*/ /* Private function prototypes -----------------------------------------------*/ void StartHSE(void); uint32_t RCC_WaitForHSEReady(void); void LED_Init(void); void LED_On(void); void LED_Blinking(uint32_t Period); Private function prototypes /* Private functions ---------------------------------------------------------*/ /** * @brief Main program * @param None * @retval None *//* ... */ int main(void) { register uint32_t frequency = 0; /* Configure Systick to 1 ms with the current frequency which should be HSI */ frequency = HSI_VALUE; LL_Init1msTick(frequency); /* Initialize LED2 */ LED_Init(); /* Start HSE */ StartHSE(); if (RCC_WaitForHSEReady() == RCC_ERROR_NONE) { /* Turn-on LED2 to indicate that HSE is ready */ LED_On(); }if (RCC_WaitForHSEReady() == RCC_ERROR_NONE) { ... } else { /* Problem to switch to HSE, blink LED2 */ LED_Blinking(LED_BLINK_ERROR); }else { ... } /* Infinite loop */ while (1) { }while (1) { ... } }{ ... } /** * Brief This function enables the interruption HSE ready, * and start the HSE as external clock. * @param None * Retval None *//* ... */ void StartHSE(void) { /* Configure NVIC for RCC */ NVIC_EnableIRQ(RCC_IRQn); NVIC_SetPriority(RCC_IRQn,0); /* Enable interrupt on HSE ready */ /* Enable the CSS Enable the HSE and set HSEBYP to use the external clock instead of an oscillator Enable HSE *//* ... */ /* Note : the clock is switched to HSE in the RCC_IRQHandler ISR */ LL_RCC_EnableIT_HSERDY(); LL_RCC_HSE_EnableCSS(); LL_RCC_HSE_EnableBypass(); LL_RCC_HSE_Enable(); }{ ... } /** * @brief Wait for HSE ready * @param None * @retval RCC_ERROR_NONE if no error *//* ... */ uint32_t RCC_WaitForHSEReady() { #if (USE_TIMEOUT == 1) /* Set timeout to 1 sec */ uint32_t timeout = TIMEOUT_VALUE;/* ... */ #endif /* USE_TIMEOUT */ /* Check that the condition is met */ while (LL_RCC_GetSysClkSource() != LL_RCC_SYS_CLKSOURCE_STATUS_HSE) { #if (USE_TIMEOUT == 1) /* Check Systick counter flag to decrement the time-out value */ if (LL_SYSTICK_IsActiveCounterFlag()) { if(--timeout == 0) { /* Time-out occurred. Return an error */ return RCC_ERROR_TIMEOUT; }if (--timeout == 0) { ... } }if (LL_SYSTICK_IsActiveCounterFlag()) { ... } /* ... */ #endif /* USE_TIMEOUT */ }while (LL_RCC_GetSysClkSource() != LL_RCC_SYS_CLKSOURCE_STATUS_HSE) { ... } return RCC_ERROR_NONE; }{ ... } /** * @brief Initialize LED2. * @param None * @retval None *//* ... */ void LED_Init(void) { /* Enable the LED2 Clock */ LED2_GPIO_CLK_ENABLE(); /* Configure IO in output push-pull mode to drive external LED2 */ LL_GPIO_SetPinMode(LED2_GPIO_PORT, LED2_PIN, LL_GPIO_MODE_OUTPUT); }{ ... } /** * @brief Turn-on LED2. * @param None * @retval None *//* ... */ void LED_On(void) { /* Turn LED2 on */ LL_GPIO_SetOutputPin(LED2_GPIO_PORT, LED2_PIN); }{ ... } /** * @brief Set LED2 to Blinking mode for an infinite loop (toggle period based on value provided as input parameter). * @param Period : Period of time (in ms) between each toggling of LED * This parameter can be user defined values. Pre-defined values used in that example are : * @arg LED_BLINK_FAST : Fast Blinking * @arg LED_BLINK_SLOW : Slow Blinking * @arg LED_BLINK_ERROR : Error specific Blinking * @retval None *//* ... */ void LED_Blinking(uint32_t Period) { /* Turn LED2 on */ LL_GPIO_SetOutputPin(LED2_GPIO_PORT, LED2_PIN); /* Toggle IO in an infinite loop */ while (1) { /* Error if LED2 is slowly blinking (1 sec. period) */ LL_GPIO_TogglePin(LED2_GPIO_PORT, LED2_PIN); LL_mDelay(Period); }while (1) { ... } }{ ... } /******************************************************************************/ /* USER IRQ HANDLER TREATMENT */ /******************************************************************************/ /** * @brief This function handles the HSE ready detection (called in RCC_IRQHandler) * @param None * @retval None *//* ... */ void HSEReady_Callback(void) { /* Switch the system clock to HSE */ LL_RCC_SetSysClkSource(LL_RCC_SYS_CLKSOURCE_HSE); /* 1ms config with HSE 8MHz*/ LL_Init1msTick(HSE_VALUE); }{ ... } /** * @brief This function handles failure detected on the HSE clock (called in NMI_Handler) * @param None * @retval None *//* ... */ void HSEFailureDetection_Callback(void) { LED_Blinking(LED_BLINK_ERROR); }{ ... } #ifdef USE_FULL_ASSERT /** * @brief Reports the name of the source file and the source line number * where the assert_param error has occurred. * @param file: pointer to the source file name * @param line: assert_param error line source number * @retval None *//* ... */ void assert_failed(uint8_t *file, uint32_t line) { /* User can add his own implementation to report the file name and line number, ex: printf("Wrong parameters value: file %s on line %d", file, line) *//* ... */ /* Infinite loop */ while (1) { }while (1) { ... } }assert_failed (uint8_t *file, uint32_t line) { ... } /* ... */#endif /** * @} *//* ... */ /** * @} *//* ... */
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