STM32CubeF4/Projects/STM324xG_EVAL/Examples/TIM/TIM_DMABurst/Src/main.c

/**
  ******************************************************************************
  * @file    TIM/TIM_DMABurst/Src/main.c 
  * @author  MCD Application Team
  * @brief   This sample code shows how to use DMA with TIM1 Update request to
  *          transfer Data from memory to TIM1 Capture Compare Register 3 (CCR3).
  ******************************************************************************
  * @attention
  *
  * <h2><center>&copy; Copyright (c) 2017 STMicroelectronics.
  * All rights reserved.</center></h2>
  *
  * This software component is licensed by ST under BSD 3-Clause license,
  * the "License"; You may not use this file except in compliance with the
  * License. You may obtain a copy of the License at:
  *                        opensource.org/licenses/BSD-3-Clause
  *
  ******************************************************************************
  */

/* Includes ------------------------------------------------------------------*/
#include "main.h"


/** @addtogroup STM32F4xx_HAL_Examples
  * @{
  */

/** @addtogroup TIM_DMABurst
  * @{
  */

/* Private typedef -----------------------------------------------------------*/
/* Private define ------------------------------------------------------------*/
/* Private macro -------------------------------------------------------------*/
/* Private variables ---------------------------------------------------------*/
/* Timer handler declaration */
TIM_HandleTypeDef    TimHandle;

/* Timer Output Compare Configuration Structure declaration */
TIM_OC_InitTypeDef sConfig;

/* Capture Compare buffer */
uint32_t aSRC_Buffer[3] = {0x0FFF, 0x0000, 0x0555};

/* Timer Period */
uint32_t uhTimerPeriod  = 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, instruction and Data caches
       - Configure the Systick to generate an interrupt each 1 msec
       - Set NVIC Group Priority to 4
       - Global MSP (MCU Support Package) initialization
     */
  HAL_Init();
  
  /* Configure the system clock to 168 MHz */
  SystemClock_Config();
  
  /* Configure LED3 */
  BSP_LED_Init(LED3);  

  /*##-1- Configure the TIM peripheral #######################################*/ 
  /* -----------------------------------------------------------------------
    TIM1 Configuration: generate 1 PWM signal using the DMA burst mode:
  
    TIM1 input clock (TIM1CLK) is set to 2 * APB2 clock (PCLK2), 
    since APB2 prescaler is different from 1.   
      TIM1CLK = 2 * PCLK2  
      PCLK2 = HCLK / 2 
      => TIM1CLK = 2 * (HCLK / 2) = HCLK = SystemCoreClock
    
    To get TIM1 counter clock at 24 MHz, the prescaler is computed as follows:
      Prescaler = (TIM1CLK / TIM1 counter clock) - 1
      Prescaler = (SystemCoreClock /24 MHz) - 1
  
    The TIM1 period is 5.8 KHz: TIM1 Frequency = TIM1 counter clock/(ARR + 1)
                                               = 24 MHz / 4096 = 5.85 KHz
    TIM1 Channel1 duty cycle = (TIM1_CCR1/ TIM1_ARR)* 100 = 33.33%
  
    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  
  ----------------------------------------------------------------------- */
  
  TimHandle.Instance = TIMx;
  
  TimHandle.Init.Period            = 0xFFFF;
  TimHandle.Init.RepetitionCounter = 0;
  TimHandle.Init.Prescaler         = (uint16_t) ((SystemCoreClock / 24000000) - 1);
  TimHandle.Init.ClockDivision     = 0;
  TimHandle.Init.CounterMode       = TIM_COUNTERMODE_UP;
  TimHandle.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_DISABLE;
  if(HAL_TIM_PWM_Init(&TimHandle) != HAL_OK)
  {
    /* Initialization Error */
    Error_Handler();
  }
  
  /*##-2- Configure the PWM channel 3 ########################################*/ 
  sConfig.OCMode     = TIM_OCMODE_PWM1;
  sConfig.OCPolarity = TIM_OCPOLARITY_HIGH;
  sConfig.Pulse      = 0xFFF;
  if(HAL_TIM_PWM_ConfigChannel(&TimHandle, &sConfig, TIM_CHANNEL_1) != HAL_OK)
  {
    /* Configuration Error */
    Error_Handler();
  }
  
  /*##-3- Start PWM signal generation in DMA mode ############################*/ 
  if(  HAL_TIM_PWM_Start(&TimHandle, TIM_CHANNEL_1) != HAL_OK)
  {
    /* Starting PWM generation Error */
    Error_Handler();
  }
  
  /*##-4- Start DMA Burst transfer ###########################################*/ 
  HAL_TIM_DMABurst_WriteStart(&TimHandle, TIM_DMABASE_ARR, TIM_DMA_UPDATE,
                              (uint32_t*)aSRC_Buffer, TIM_DMABURSTLENGTH_3TRANSFERS);
  
  /* Infinite loop */
  while (1)
  {
  }
}

/**
  * @brief  This function is executed in case of error occurrence.
  * @param  None
  * @retval None
  */
static void Error_Handler(void)
{
    /* Turn LED3 on */
    BSP_LED_On(LED3);
    while(1)
    {
    }
}

/**
  * @brief  System Clock Configuration
  *         The system Clock is configured as follow : 
  *            System Clock source            = PLL (HSE)
  *            SYSCLK(Hz)                     = 168000000
  *            HCLK(Hz)                       = 168000000
  *            AHB Prescaler                  = 1
  *            APB1 Prescaler                 = 4
  *            APB2 Prescaler                 = 2
  *            HSE Frequency(Hz)              = 25000000
  *            PLL_M                          = 25
  *            PLL_N                          = 336
  *            PLL_P                          = 2
  *            PLL_Q                          = 7
  *            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;

  /* 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_ON;
  RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
  RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
  RCC_OscInitStruct.PLL.PLLM = 25;
  RCC_OscInitStruct.PLL.PLLN = 336;
  RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV2;
  RCC_OscInitStruct.PLL.PLLQ = 7;
  HAL_RCC_OscConfig(&RCC_OscInitStruct);
  
  /* 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;  
  HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_5);

  /* STM32F405x/407x/415x/417x Revision Z devices: prefetch is supported  */
  if (HAL_GetREVID() == 0x1001)
  {
    /* Enable the Flash prefetch */
    __HAL_FLASH_PREFETCH_BUFFER_ENABLE();
  }
}

#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

/**
  * @}
  */

/**
  * @}
  */

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