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/**
******************************************************************************
* @file TIM/TIM_DMA/Src/main.c
* @author MCD Application Team
* @brief This sample code shows how to use DMA with TIM2 Update request to
* transfer Data from memory to TIM2 Capture Compare Register 3 (CCR3).
******************************************************************************
* @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_HAL_Examples
* @{
*/
/** @addtogroup TIM_DMA
* @{
*/
/* 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 aCCValue_Buffer[3] = {0, 0, 0};
/* Timer Period*/
uint32_t uwTimerPeriod = 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)
{
/* This sample code shows how to use DMA with TIM2 Update request to transfer
Data from memory to TIM2 Capture Compare Register 3 (CCR3), through the
STM32F4xx HAL API. To proceed, 3 steps are required */
/* 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 LED3 */
BSP_LED_Init(LED3);
/* Compute the value of ARR register to generate signal frequency at 17.57 Khz */
uwTimerPeriod = (uint32_t)(((SystemCoreClock/2) / 17570) - 1);
/* Compute CCR1 value to generate a duty cycle at 75% */
aCCValue_Buffer[0] = (uint32_t)(((uint32_t) 75 * (uwTimerPeriod - 1)) / 100);
/* Compute CCR2 value to generate a duty cycle at 50% */
aCCValue_Buffer[1] = (uint32_t)(((uint32_t) 50 * (uwTimerPeriod - 1)) / 100);
/* Compute CCR3 value to generate a duty cycle at 25% */
aCCValue_Buffer[2] = (uint32_t)(((uint32_t) 25 * (uwTimerPeriod - 1)) / 100);
/*##-1- Configure the TIM peripheral #######################################*/
/* ---------------------------------------------------------------------------
TIM2 input clock (TIM2CLK) is set to APB1 clock (PCLK1)x2, since APB1
prescaler is 4.
TIM2CLK = PCLK1*2
PCLK1 = HCLK/2
=> TIM2CLK = HCLK/2 = SystemCoreClock/2
TIM2CLK = (SystemCoreClock/2), Prescaler = 0, TIM2 counter clock = (SystemCoreClock/2)
SystemCoreClock is set to 180 MHz for STM32F4xx devices.
The objective is to configure TIM2 channel 3 to generate a PWM
signal with a frequency equal to 17.57 KHz:
- TIM2_Period = ((SystemCoreClock/2) / 17570) - 1
and a variable duty cycle that is changed by the DMA after a specific number of
Update DMA request.
The number of this repetitive requests is defined by the TIM2 Repetition counter,
each 4 Update Requests, the TIM2 Channel 3 Duty Cycle changes to the next new
value defined by the aCCValue_Buffer.
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 TIM2 peripheral as follows:
+ Period = TimerPeriod (To have an output frequency equal to 17.570 KHz)
+ Repetition Counter = 3
+ Prescaler = 0
+ ClockDivision = 0
+ Counter direction = Up
*/
TimHandle.Instance = TIMx;
TimHandle.Init.Period = uwTimerPeriod;
TimHandle.Init.RepetitionCounter = 3;
TimHandle.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_DISABLE;
TimHandle.Init.Prescaler = 0;
TimHandle.Init.ClockDivision = 0;
TimHandle.Init.CounterMode = TIM_COUNTERMODE_UP;
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 = aCCValue_Buffer[0];
sConfig.OCNPolarity = TIM_OCNPOLARITY_HIGH;
sConfig.OCFastMode = TIM_OCFAST_DISABLE;
sConfig.OCIdleState = TIM_OCIDLESTATE_RESET;
sConfig.OCNIdleState = TIM_OCNIDLESTATE_RESET;
if (HAL_TIM_PWM_ConfigChannel(&TimHandle, &sConfig, TIM_CHANNEL_3) != HAL_OK)
{
/* Configuration Error */
Error_Handler();
}
/*##-3- Start PWM signal generation in DMA mode ############################*/
if (HAL_TIM_PWM_Start_DMA(&TimHandle, TIM_CHANNEL_3, aCCValue_Buffer, 3) != HAL_OK)
{
/* Starting 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 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) = 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
* 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_ON;
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
/**
* @}
*/
/**
* @}
*/
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