STM32CubeF0/Projects/STM32F091RC-Nucleo/Examples/TIM/TIM_TimeBase/Src/main.c

/**
  ******************************************************************************
  * @file    TIM/TIM_TimeBase/Src/main.c
  * @author  MCD Application Team
  * @brief   This sample code shows how to use STM32F0xx TIM HAL API to generate
  *          a time base of one second with the corresponding Interrupt request.
  ******************************************************************************
  * @attention
  *
  * Copyright (c) 2016 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 STM32F0xx_HAL_Examples
  * @{
  */

/** @addtogroup TIM_TimeBase
  * @{
  */

/* Private typedef -----------------------------------------------------------*/
/* Private define ------------------------------------------------------------*/
/* Private macro -------------------------------------------------------------*/
/* Private variables ---------------------------------------------------------*/
/* TIM handle declaration */
TIM_HandleTypeDef    TimHandle;

/* Prescaler declaration */
uint32_t uwPrescalerValue = 0;

/* Private function prototypes -----------------------------------------------*/
static void SystemClock_Config(void);
static void Error_Handler(void);

/* Private functions ---------------------------------------------------------*/

/**
  * @brief  Main program
  * @param  None
  * @retval None
  */
int main(void)
{

  /* STM32F0xx HAL library initialization:
       - Configure the Flash prefetch
       - Systick timer is configured by default as source of time base, but user 
         can eventually implement his proper time base source (a general purpose 
         timer for example or other time source), keeping in mind that Time base 
         duration should be kept 1ms since PPP_TIMEOUT_VALUEs are defined and 
         handled in milliseconds basis.
       - Low Level Initialization
     */
  HAL_Init();

  /* Configure LED2 */
  BSP_LED_Init(LED2);

  /* Configure the system clock to 48 MHz */
  SystemClock_Config();

  /*##-1- Configure the TIM peripheral #######################################*/
  /* -----------------------------------------------------------------------
    In this example TIM2 input clock (TIM2CLK)  is set to APB1 clock (PCLK1),
    since APB1 prescaler is equal to 1.
      TIM2CLK = PCLK1
      PCLK1 = HCLK
      => TIM2CLK = HCLK = SystemCoreClock
    To get TIM2 counter clock at 10 KHz, the Prescaler is computed as following:
    Prescaler = (TIM2CLK / TIM2 counter clock) - 1
    Prescaler = (SystemCoreClock /10 KHz) - 1

    Note:
     SystemCoreClock variable holds HCLK frequency and is defined in system_stm32f0xx.c file.
     Each time the core clock (HCLK) changes, user had to update SystemCoreClock
     variable value. Otherwise, any configuration based on this variable will be incorrect.
     This variable is updated in three ways:
      1) by calling CMSIS function SystemCoreClockUpdate()
      2) by calling HAL API function HAL_RCC_GetSysClockFreq()
      3) each time HAL_RCC_ClockConfig() is called to configure the system clock frequency
  ----------------------------------------------------------------------- */

  /* Compute the prescaler value to have TIMx counter clock equal to 10000 Hz */
  uwPrescalerValue = (uint32_t)(SystemCoreClock / 10000) - 1;

  /* Set TIMx instance */
  TimHandle.Instance = TIMx;

  /* Initialize TIMx peripheral as follows:
       + Period = 10000 - 1
       + Prescaler = (SystemCoreClock/10000) - 1
       + ClockDivision = 0
       + Counter direction = Up
  */
  TimHandle.Init.Period            = 10000 - 1;
  TimHandle.Init.Prescaler         = uwPrescalerValue;
  TimHandle.Init.ClockDivision     = 0;
  TimHandle.Init.CounterMode       = TIM_COUNTERMODE_UP;
  TimHandle.Init.RepetitionCounter = 0;
  TimHandle.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_DISABLE;
  if (HAL_TIM_Base_Init(&TimHandle) != HAL_OK)
  {
    /* Initialization Error */
    Error_Handler();
  }

  /*##-2- Start the TIM Base generation in interrupt mode ####################*/
  /* Start Channel1 */
  if (HAL_TIM_Base_Start_IT(&TimHandle) != HAL_OK)
  {
    /* Starting Error */
    Error_Handler();
  }

  while (1)
  {
  }
}

/**
  * @brief  Period elapsed callback in non blocking mode
  * @param  htim : TIM handle
  * @retval None
  */
void HAL_TIM_PeriodElapsedCallback(TIM_HandleTypeDef *htim)
{
  BSP_LED_Toggle(LED2);
}

/**
  * @brief  System Clock Configuration
  *         The system Clock is configured as follow : 
  *            System Clock source            = PLL (HSI48)
  *            SYSCLK(Hz)                     = 48000000
  *            HCLK(Hz)                       = 48000000
  *            AHB Prescaler                  = 1
  *            APB1 Prescaler                 = 1
  *            HSI Frequency(Hz)              = 48000000
  *            PREDIV                         = 2
  *            PLLMUL                         = 2
  *            Flash Latency(WS)              = 1
  * @param  None
  * @retval None
  */
static void SystemClock_Config(void)
{
  RCC_ClkInitTypeDef RCC_ClkInitStruct;
  RCC_OscInitTypeDef RCC_OscInitStruct;
  
  /* Select HSI48 Oscillator as PLL source */
  RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI48;
  RCC_OscInitStruct.HSI48State = RCC_HSI48_ON;
  RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
  RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSI48;
  RCC_OscInitStruct.PLL.PREDIV = RCC_PREDIV_DIV2;
  RCC_OscInitStruct.PLL.PLLMUL = RCC_PLL_MUL2;
  if (HAL_RCC_OscConfig(&RCC_OscInitStruct)!= HAL_OK)
  {
    Error_Handler();
  }

  /* Select PLL as system clock source and configure the HCLK and PCLK1 clocks dividers */
  RCC_ClkInitStruct.ClockType = (RCC_CLOCKTYPE_SYSCLK | RCC_CLOCKTYPE_HCLK | RCC_CLOCKTYPE_PCLK1);
  RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
  RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
  RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV1;
  if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_1)!= HAL_OK)
  {
    Error_Handler();
  }
}

/**
  * @brief  This function is executed in case of error occurrence.
  * @param  None
  * @retval None
  */
static void Error_Handler(void)
{
  /* Turn LED2 on */
  BSP_LED_On(LED2);
  while (1)
  {
  }
}
#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\r\n", file, line) */

  /* Infinite loop */
  while (1)
  {
  }
}

#endif

/**
  * @}
  */

/**
  * @}
  */