Question
Timer Compare Output using DMA - STM32F3Discovery
Hello,
I am attempting to generate a waveform with a period of 33ms. In-between each period, I need to toggle the timer output 5 times with a varying timescale. My initial thought is to do this using a timer in output compare mode and then update the CRR register with the 5 pulses from the DMA in a circular mode.
___________ ___________ ___________
| 5700 |___3000___| 4700 |___3000___| 10000 |_________________________
<------------------------------------33ms------------------------------------>
So far, the pin toggles but at intervals that are over the values in the array. Below is the waveform as seen on a logic analyser. I am certain that the input clock is correct at 36MHz and the period should be 33ms.
I have included the following functions to the CubeMX generated code to ensure the timer is started with DMA.
HAL_TIM_OC_DelayElapsedCallback(&htim17);
//enable dma
HAL_TIM_OC_Start_DMA(&htim17, TIM_CHANNEL_1, (uint32_t*)wave_buffer, 5);At this point, I'm not sure what I'm missing as I've followed the steps in the reference manual and application notes to be on par with what I need. I appreciate any help with what I may be missing, thank you.
PS- code is below
/* USER CODE BEGIN Header */
/**
******************************************************************************
* @file : main.c
* @brief : Main program body
******************************************************************************
**/
/* Private variables ---------------------------------------------------------*/
TIM_HandleTypeDef htim17;
DMA_HandleTypeDef hdma_tim17_ch1_up;
/* USER CODE BEGIN PV */
uint16_t wave_buffer[5] = {5700, 3000, 4700, 3000, 10000};
/* USER CODE END PV */
/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_DMA_Init(void);
static void MX_TIM17_Init(void);
/* USER CODE BEGIN PFP */
/* USER CODE END PFP */
/* Private user code ---------------------------------------------------------*/
/* USER CODE BEGIN 0 */
/* USER CODE END 0 */
/**
* @brief The application entry point.
* @retval int
*/
int main(void)
{
/* USER CODE BEGIN 1 */
/*
___________ ___________ ___________
| 5700 |___3000___| 4700 |___3000___| 10000 |_________________________
<------------------------------------33ms------------------------------------>
*/
/* USER CODE END 1 */
/* MCU Configuration--------------------------------------------------------*/
/* Reset of all peripherals, Initializes the Flash interface and the Systick. */
HAL_Init();
/* USER CODE BEGIN Init */
/* USER CODE END Init */
/* Configure the system clock */
SystemClock_Config();
/* USER CODE BEGIN SysInit */
/* USER CODE END SysInit */
/* Initialize all configured peripherals */
MX_GPIO_Init();
MX_DMA_Init();
MX_TIM17_Init();
/* USER CODE BEGIN 2 */
// HAL_TIM_OC_DelayElapsedCallback(&htim15);
HAL_TIM_OC_DelayElapsedCallback(&htim17);
//enable dma
HAL_TIM_OC_Start_DMA(&htim17, TIM_CHANNEL_1, (uint32_t*)wave_buffer, 5);
/* USER CODE END 2 */
/* Infinite loop */
/* USER CODE BEGIN WHILE */
while (1)
{
/* USER CODE END WHILE */
/* USER CODE BEGIN 3 */
}
/* USER CODE END 3 */
}
/**
* @brief System Clock Configuration
* @retval None
*/
void SystemClock_Config(void)
{
RCC_OscInitTypeDef RCC_OscInitStruct = {0};
RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};
/** Initializes the RCC Oscillators according to the specified parameters
* in the RCC_OscInitTypeDef structure.
*/
RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI;
RCC_OscInitStruct.HSIState = RCC_HSI_ON;
RCC_OscInitStruct.HSICalibrationValue = RCC_HSICALIBRATION_DEFAULT;
RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSI;
RCC_OscInitStruct.PLL.PLLMUL = RCC_PLL_MUL9;
if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
{
Error_Handler();
}
/** Initializes the CPU, AHB and APB buses clocks
*/
RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK
|RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2;
RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV2;
RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;
if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_1) != HAL_OK)
{
Error_Handler();
}
}
/**
* @brief TIM17 Initialization Function
* @PAram None
* @retval None
*/
static void MX_TIM17_Init(void)
{
/* USER CODE BEGIN TIM17_Init 0 */
/* USER CODE END TIM17_Init 0 */
TIM_OC_InitTypeDef sConfigOC = {0};
TIM_BreakDeadTimeConfigTypeDef sBreakDeadTimeConfig = {0};
/* USER CODE BEGIN TIM17_Init 1 */
/* USER CODE END TIM17_Init 1 */
htim17.Instance = TIM17;
htim17.Init.Prescaler = 36-1;
htim17.Init.CounterMode = TIM_COUNTERMODE_UP;
htim17.Init.Period = 33000-1;
htim17.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
htim17.Init.RepetitionCounter = 0;
htim17.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_DISABLE;
if (HAL_TIM_Base_Init(&htim17) != HAL_OK)
{
Error_Handler();
}
if (HAL_TIM_OC_Init(&htim17) != HAL_OK)
{
Error_Handler();
}
sConfigOC.OCMode = TIM_OCMODE_TOGGLE;
sConfigOC.Pulse = 0;
sConfigOC.OCPolarity = TIM_OCPOLARITY_LOW;
sConfigOC.OCNPolarity = TIM_OCNPOLARITY_HIGH;
sConfigOC.OCFastMode = TIM_OCFAST_DISABLE;
sConfigOC.OCIdleState = TIM_OCIDLESTATE_RESET;
sConfigOC.OCNIdleState = TIM_OCNIDLESTATE_RESET;
if (HAL_TIM_OC_ConfigChannel(&htim17, &sConfigOC, TIM_CHANNEL_1) != HAL_OK)
{
Error_Handler();
}
__HAL_TIM_ENABLE_OCxPRELOAD(&htim17, TIM_CHANNEL_1);
sBreakDeadTimeConfig.OffStateRunMode = TIM_OSSR_DISABLE;
sBreakDeadTimeConfig.OffStateIDLEMode = TIM_OSSI_DISABLE;
sBreakDeadTimeConfig.LockLevel = TIM_LOCKLEVEL_OFF;
sBreakDeadTimeConfig.DeadTime = 0;
sBreakDeadTimeConfig.BreakState = TIM_BREAK_DISABLE;
sBreakDeadTimeConfig.BreakPolarity = TIM_BREAKPOLARITY_HIGH;
sBreakDeadTimeConfig.BreakFilter = 0;
sBreakDeadTimeConfig.AutomaticOutput = TIM_AUTOMATICOUTPUT_DISABLE;
if (HAL_TIMEx_ConfigBreakDeadTime(&htim17, &sBreakDeadTimeConfig) != HAL_OK)
{
Error_Handler();
}
/* USER CODE BEGIN TIM17_Init 2 */
/* USER CODE END TIM17_Init 2 */
HAL_TIM_MspPostInit(&htim17);
}
/**
* Enable DMA controller clock
*/
static void MX_DMA_Init(void)
{
/* DMA controller clock enable */
__HAL_RCC_DMA1_CLK_ENABLE();
/* DMA interrupt init */
/* DMA1_Channel1_IRQn interrupt configuration */
HAL_NVIC_SetPriority(DMA1_Channel1_IRQn, 0, 0);
HAL_NVIC_EnableIRQ(DMA1_Channel1_IRQn);
}
/**
* @brief GPIO Initialization Function
* @PAram None
* @retval None
*/
static void MX_GPIO_Init(void)
{
/* USER CODE BEGIN MX_GPIO_Init_1 */
/* USER CODE END MX_GPIO_Init_1 */
/* GPIO Ports Clock Enable */
__HAL_RCC_GPIOF_CLK_ENABLE();
__HAL_RCC_GPIOA_CLK_ENABLE();
/* USER CODE BEGIN MX_GPIO_Init_2 */
/* USER CODE END MX_GPIO_Init_2 */
}
/* USER CODE BEGIN 4 */
/* USER CODE END 4 */
/**
* @brief This function is executed in case of error occurrence.
* @retval None
*/
void Error_Handler(void)
{
/* USER CODE BEGIN Error_Handler_Debug */
/* User can add his own implementation to report the HAL error return state */
__disable_irq();
while (1)
{
}
/* USER CODE END Error_Handler_Debug */
}
#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 CODE BEGIN 6 */
/* 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) */
/* USER CODE END 6 */
}
#endif /* USE_FULL_ASSERT */
/* USER CODE BEGIN Header */
/**
******************************************************************************
* @file stm32f3xx_hal_msp.c
* @brief This file provides code for the MSP Initialization
* and de-Initialization codes.
******************************************************************************
*/
/* Includes ------------------------------------------------------------------*/
#include "main.h"
extern DMA_HandleTypeDef hdma_tim17_ch1_up;
void HAL_TIM_MspPostInit(TIM_HandleTypeDef *htim);
/**
* Initializes the Global MSP.
*/
void HAL_MspInit(void)
{
/* USER CODE BEGIN MspInit 0 */
/* USER CODE END MspInit 0 */
__HAL_RCC_SYSCFG_CLK_ENABLE();
__HAL_RCC_PWR_CLK_ENABLE();
/* System interrupt init*/
/* USER CODE BEGIN MspInit 1 */
/* USER CODE END MspInit 1 */
}
/**
* @brief TIM_Base MSP Initialization
* This function configures the hardware resources used in this example
* @PAram htim_base: TIM_Base handle pointer
* @retval None
*/
void HAL_TIM_Base_MspInit(TIM_HandleTypeDef* htim_base)
{
if(htim_base->Instance==TIM17)
{
/* USER CODE BEGIN TIM17_MspInit 0 */
/* USER CODE END TIM17_MspInit 0 */
/* Peripheral clock enable */
__HAL_RCC_TIM17_CLK_ENABLE();
/* TIM17 DMA Init */
/* TIM17_CH1_UP Init */
hdma_tim17_ch1_up.Instance = DMA1_Channel1;
hdma_tim17_ch1_up.Init.Direction = DMA_MEMORY_TO_PERIPH;
hdma_tim17_ch1_up.Init.PeriphInc = DMA_PINC_DISABLE;
hdma_tim17_ch1_up.Init.MemInc = DMA_MINC_ENABLE;
hdma_tim17_ch1_up.Init.PeriphDataAlignment = DMA_PDATAALIGN_HALFWORD;
hdma_tim17_ch1_up.Init.MemDataAlignment = DMA_MDATAALIGN_HALFWORD;
hdma_tim17_ch1_up.Init.Mode = DMA_CIRCULAR;
hdma_tim17_ch1_up.Init.Priority = DMA_PRIORITY_HIGH;
if (HAL_DMA_Init(&hdma_tim17_ch1_up) != HAL_OK)
{
Error_Handler();
}
/* Several peripheral DMA handle pointers point to the same DMA handle.
Be aware that there is only one channel to perform all the requested DMAs. */
__HAL_LINKDMA(htim_base,hdma[TIM_DMA_ID_CC1],hdma_tim17_ch1_up);
__HAL_LINKDMA(htim_base,hdma[TIM_DMA_ID_UPDATE],hdma_tim17_ch1_up);
/* TIM17 interrupt Init */
HAL_NVIC_SetPriority(TIM1_TRG_COM_TIM17_IRQn, 0, 0);
HAL_NVIC_EnableIRQ(TIM1_TRG_COM_TIM17_IRQn);
/* USER CODE BEGIN TIM17_MspInit 1 */
/* USER CODE END TIM17_MspInit 1 */
}
}
void HAL_TIM_MspPostInit(TIM_HandleTypeDef* htim)
{
GPIO_InitTypeDef GPIO_InitStruct = {0};
if(htim->Instance==TIM17)
{
/* USER CODE BEGIN TIM17_MspPostInit 0 */
/* USER CODE END TIM17_MspPostInit 0 */
__HAL_RCC_GPIOA_CLK_ENABLE();
/**TIM17 GPIO Configuration
PA7 ------> TIM17_CH1
*/
GPIO_InitStruct.Pin = GPIO_PIN_7;
GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
GPIO_InitStruct.Pull = GPIO_NOPULL;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
GPIO_InitStruct.Alternate = GPIO_AF1_TIM17;
HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
/* USER CODE BEGIN TIM17_MspPostInit 1 */
/* USER CODE END TIM17_MspPostInit 1 */
}
}
/**
* @brief TIM_Base MSP De-Initialization
* This function freeze the hardware resources used in this example
* @PAram htim_base: TIM_Base handle pointer
* @retval None
*/
void HAL_TIM_Base_MspDeInit(TIM_HandleTypeDef* htim_base)
{
if(htim_base->Instance==TIM17)
{
/* USER CODE BEGIN TIM17_MspDeInit 0 */
/* USER CODE END TIM17_MspDeInit 0 */
/* Peripheral clock disable */
__HAL_RCC_TIM17_CLK_DISABLE();
/* TIM17 DMA DeInit */
HAL_DMA_DeInit(htim_base->hdma[TIM_DMA_ID_CC1]);
HAL_DMA_DeInit(htim_base->hdma[TIM_DMA_ID_UPDATE]);
/* TIM17 interrupt DeInit */
HAL_NVIC_DisableIRQ(TIM1_TRG_COM_TIM17_IRQn);
/* USER CODE BEGIN TIM17_MspDeInit 1 */
/* USER CODE END TIM17_MspDeInit 1 */
}
}
/* USER CODE BEGIN 1 */
/* USER CODE END 1 */
