text: /**
    ******************************************************************************
    * @file    TIM/TIM_PWMOutput/Src/main.c
    * @author  MCD Application Team
    * @brief   This sample code shows how to use STM32F4xx TIM HAL API to generate
    *          4 signals in PWM.
    ******************************************************************************
    * @attention
    *
    * <h2><center>&copy; COPYRIGHT(c) 2017 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.
    *
    ******************************************************************************
    */
  
  /* Includes ------------------------------------------------------------------*/
  #include "main.h"
  
  /** @addtogroup STM32F4xx_HAL_Examples
    * @{
    */
  
  /** @addtogroup TIM_PWMOutput
    * @{
    */
  
  /* Private typedef -----------------------------------------------------------*/
  #define  PERIOD_VALUE       (uint32_t)(666 - 1)  /* Period Value  */
  #define  PULSE1_VALUE       (uint32_t)(PERIOD_VALUE/2)        /* Capture Compare 1 Value  */
  #define  PULSE2_VALUE       (uint32_t)(PERIOD_VALUE*37.5/100) /* Capture Compare 2 Value  */
  #define  PULSE3_VALUE       (uint32_t)(PERIOD_VALUE/4)        /* Capture Compare 3 Value  */
  #define  PULSE4_VALUE       (uint32_t)(PERIOD_VALUE*12.5/100) /* Capture Compare 4 Value  */
  
  /* Private define ------------------------------------------------------------*/
  /* Private macro -------------------------------------------------------------*/
  /* Private variables ---------------------------------------------------------*/
  /* Timer handler declaration */
  TIM_HandleTypeDef    TimHandle;
  
  /* Timer Output Compare Configuration Structure declaration */
  TIM_OC_InitTypeDef sConfig;
  
  /* Counter Prescaler value */
  uint32_t uhPrescalerValue = 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)
  {
    /* STM32F4xx 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.
         - Set NVIC Group Priority to 4
         - Low Level Initialization
       */
    HAL_Init();
  
    /* Configure the system clock to 180 MHz */
    SystemClock_Config();
  
    /* Configure LED2 */
    BSP_LED_Init(LED2);
  
    /* Compute the prescaler value to have TIM3 counter clock equal to 15000000 Hz */
    uhPrescalerValue = (uint32_t)((SystemCoreClock/2) / 15000000) - 1;
  
    /*##-1- Configure the TIM peripheral #######################################*/
    /* -----------------------------------------------------------------------
    TIM3 Configuration: generate 4 PWM signals with 4 different duty cycles.
  
      In this example TIM3 input clock (TIM3CLK) is set to APB1 clock x 2,
      since APB1 prescaler is equal to 2.
        TIM3CLK = APB1CLK*2
        APB1CLK = HCLK/4
        => TIM3CLK = HCLK / 2 = SystemCoreClock / 2
  
      To get TIM3 counter clock at 16 MHz, the prescaler is computed as follows:
         Prescaler = (TIM3CLK / TIM3 counter clock) - 1
         Prescaler = ((SystemCoreClock / 2) /15 MHz) - 1
  
      To get TIM3 output clock at 22,5 KHz, the period (ARR)) is computed as follows:
         ARR = (TIM3 counter clock / TIM3 output clock) - 1
             = 665
  
      TIM3 Channel1 duty cycle = (TIM3_CCR1/ TIM3_ARR + 1)* 100 = 50%
      TIM3 Channel2 duty cycle = (TIM3_CCR2/ TIM3_ARR + 1)* 100 = 37.5%
      TIM3 Channel3 duty cycle = (TIM3_CCR3/ TIM3_ARR + 1)* 100 = 25%
      TIM3 Channel4 duty cycle = (TIM3_CCR4/ TIM3_ARR + 1)* 100 = 12.5%
  
      Note:
       SystemCoreClock variable holds HCLK frequency and is defined in system_stm32f4xx.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
    ----------------------------------------------------------------------- */
  
    /* Initialize TIMx peripheral as follows:
         + Prescaler = ((SystemCoreClock / 2) / 15000000) - 1
         + Period = (666 - 1)
         + ClockDivision = 0
         + Counter direction = Up
    */
    TimHandle.Instance = TIMx;
  
    TimHandle.Init.Prescaler         = uhPrescalerValue;
    TimHandle.Init.Period            = PERIOD_VALUE;
    TimHandle.Init.ClockDivision     = 0;
    TimHandle.Init.CounterMode       = TIM_COUNTERMODE_UP;
    TimHandle.Init.RepetitionCounter = 0;
    TimHandle.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_DISABLE;
    if (HAL_TIM_PWM_Init(&TimHandle) != HAL_OK)
    {
      /* Initialization Error */
      Error_Handler();
    }
  
    /*##-2- Configure the PWM channels #########################################*/
    /* Common configuration for all channels */
    sConfig.OCMode       = TIM_OCMODE_PWM1;
    sConfig.OCPolarity   = TIM_OCPOLARITY_HIGH;
    sConfig.OCFastMode   = TIM_OCFAST_DISABLE;
    sConfig.OCNPolarity  = TIM_OCNPOLARITY_HIGH;
    sConfig.OCNIdleState = TIM_OCNIDLESTATE_RESET;
  
    sConfig.OCIdleState  = TIM_OCIDLESTATE_RESET;
  
    /* Set the pulse value for channel 1 */
    sConfig.Pulse = PULSE1_VALUE;
    if (HAL_TIM_PWM_ConfigChannel(&TimHandle, &sConfig, TIM_CHANNEL_1) != HAL_OK)
    {
      /* Configuration Error */
      Error_Handler();
    }
  
    /* Set the pulse value for channel 2 */
    sConfig.Pulse = PULSE2_VALUE;
    if (HAL_TIM_PWM_ConfigChannel(&TimHandle, &sConfig, TIM_CHANNEL_2) != HAL_OK)
    {
      /* Configuration Error */
      Error_Handler();
    }
  
    /* Set the pulse value for channel 3 */
    sConfig.Pulse = PULSE3_VALUE;
    if (HAL_TIM_PWM_ConfigChannel(&TimHandle, &sConfig, TIM_CHANNEL_3) != HAL_OK)
    {
      /* Configuration Error */
      Error_Handler();
    }
  
    /* Set the pulse value for channel 4 */
    sConfig.Pulse = PULSE4_VALUE;
    if (HAL_TIM_PWM_ConfigChannel(&TimHandle, &sConfig, TIM_CHANNEL_4) != HAL_OK)
    {
      /* Configuration Error */
      Error_Handler();
    }
  
    /*##-3- Start PWM signals generation #######################################*/
    /* Start channel 1 */
    if (HAL_TIM_PWM_Start(&TimHandle, TIM_CHANNEL_1) != HAL_OK)
    {
      /* PWM Generation Error */
      Error_Handler();
    }
    /* Start channel 2 */
    if (HAL_TIM_PWM_Start(&TimHandle, TIM_CHANNEL_2) != HAL_OK)
    {
      /* PWM Generation Error */
      Error_Handler();
    }
    /* Start channel 3 */
    if (HAL_TIM_PWM_Start(&TimHandle, TIM_CHANNEL_3) != HAL_OK)
    {
      /* PWM generation Error */
      Error_Handler();
    }
    /* Start channel 4 */
    if (HAL_TIM_PWM_Start(&TimHandle, TIM_CHANNEL_4) != HAL_OK)
    {
      /* PWM generation Error */
      Error_Handler();
    }
  
    while (1)
    {
    }
  
  }
  
  /**
    * @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)
    {
    }
  }
  
  /**
    * @brief  System Clock Configuration
    *         The system Clock is configured as follow : 
    *            System Clock source            = PLL (HSE)
    *            SYSCLK(Hz)                     = 180000000
    *            HCLK(Hz)                       = 180000000
    *            AHB Prescaler                  = 1
    *            APB1 Prescaler                 = 4
    *            APB2 Prescaler                 = 2
    *            HSE Frequency(Hz)              = 8000000
    *            PLL_M                          = 8
    *            PLL_N                          = 360
    *            PLL_P                          = 2
    *            PLL_Q                          = 7
    *            PLL_R                          = 2
    *            VDD(V)                         = 3.3
    *            Main regulator output voltage  = Scale1 mode
    *            Flash Latency(WS)              = 5
    * @param  None
    * @retval None
    */
  static void SystemClock_Config(void)
  {
    RCC_ClkInitTypeDef RCC_ClkInitStruct;
    RCC_OscInitTypeDef RCC_OscInitStruct;
    HAL_StatusTypeDef ret = HAL_OK;
  
    /* Enable Power Control clock */
    __HAL_RCC_PWR_CLK_ENABLE();
  
    /* The voltage scaling allows optimizing the power consumption when the device is 
       clocked below the maximum system frequency, to update the voltage scaling value 
       regarding system frequency refer to product datasheet.  */
    __HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE1);
  
    /* Enable HSE Oscillator and activate PLL with HSE as source */
    RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE;
    RCC_OscInitStruct.HSEState = RCC_HSE_BYPASS;
    RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
    RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
    RCC_OscInitStruct.PLL.PLLM = 8;
    RCC_OscInitStruct.PLL.PLLN = 360;
    RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV2;
    RCC_OscInitStruct.PLL.PLLQ = 7;
    RCC_OscInitStruct.PLL.PLLR = 2;
    
    ret = HAL_RCC_OscConfig(&RCC_OscInitStruct);
    if(ret != HAL_OK)
    {
      while(1) { ; }
    }
    
    /* Activate the OverDrive to reach the 180 MHz Frequency */  
    ret = HAL_PWREx_EnableOverDrive();
    if(ret != HAL_OK)
    {
      while(1) { ; }
    }
    
    /* Select PLL as system clock source and configure the HCLK, PCLK1 and PCLK2 clocks dividers */
    RCC_ClkInitStruct.ClockType = (RCC_CLOCKTYPE_SYSCLK | RCC_CLOCKTYPE_HCLK | RCC_CLOCKTYPE_PCLK1 | RCC_CLOCKTYPE_PCLK2);
    RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
    RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
    RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV4;  
    RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV2;  
    
    ret = HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_5);
    if(ret != HAL_OK)
    {
      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
  
  /**
    * @}
    */
  
  /**
    * @}
    */
  
  /************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/
  