Can't get DAC to work on STM32F3Discovery board

[c64]

Hi,

First of all, I'm very new to the STM32 family of microcontrollers. I'm trying to output a sine wave on the DAC (pin PA4 on the discovery board) using DMA2 channel 3, triggered by TIM6. I use the STM32CubeMX to generate the code, then I manually add the sine wave as well as these lines after initializing the peripherals:

  HAL_TIM_Base_Start(&htim6);
  HAL_DAC_Start(&hdac,DAC_CHANNEL_1);
  HAL_DAC_Start_DMA(&hdac, DAC_CHANNEL_1, (uint32_t*)sine_wave_array, 32, DAC_ALIGN_12B_R);

However, there is no signal generated on PA4. Here is my complete code (I have left everything else the way the code generator made the file. Again, I've only been using the STM32 controller for a couple of days, so it's probably just a silly mistake. Anyways, here's the main.c file:

/* USER CODE BEGIN Header */
/**
  ******************************************************************************
  * @file           : main.c
  * @brief          : Main program body
  ******************************************************************************
  * @attention
  *
  * <h2><center>&copy; Copyright (c) 2019 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
  *
  ******************************************************************************
  */
/* USER CODE END Header */
 
/* Includes ------------------------------------------------------------------*/
#include "main.h"
 
/* Private includes ----------------------------------------------------------*/
/* USER CODE BEGIN Includes */
 
/* USER CODE END Includes */
 
/* Private typedef -----------------------------------------------------------*/
/* USER CODE BEGIN PTD */
 
/* USER CODE END PTD */
 
/* Private define ------------------------------------------------------------*/
/* USER CODE BEGIN PD */
 
/* USER CODE END PD */
 
/* Private macro -------------------------------------------------------------*/
/* USER CODE BEGIN PM */
 
/* USER CODE END PM */
 
/* Private variables ---------------------------------------------------------*/
DAC_HandleTypeDef hdac;
 
TIM_HandleTypeDef htim6;
DMA_HandleTypeDef hdma_tim6_up;
 
/* USER CODE BEGIN PV */
const uint16_t sine_wave_array[32] = {2047, 1648, 1264, 910, 600,  345,
                   156, 39,  0,  39,  156,  345,
                   600, 910, 1264, 1648, 2048, 2447,
                   2831, 3185, 3495, 3750, 3939, 4056,
                   4095, 4056, 3939, 3750, 3495, 3185,
                   2831, 2447};
 
/* 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_DAC_Init(void);
static void MX_TIM6_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 */
 
  /* 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_DAC_Init();
  MX_TIM6_Init();
  /* USER CODE BEGIN 2 */
  HAL_TIM_Base_Start(&htim6);
  HAL_DAC_Start(&hdac,DAC_CHANNEL_1);
  HAL_DAC_Start_DMA(&hdac, DAC_CHANNEL_1, (uint32_t*)sine_wave_array, 32, DAC_ALIGN_12B_R);
  /* 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 CPU, AHB and APB busses clocks 
  */
  RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE;
  RCC_OscInitStruct.HSEState = RCC_HSE_BYPASS;
  RCC_OscInitStruct.HSEPredivValue = RCC_HSE_PREDIV_DIV1;
  RCC_OscInitStruct.HSIState = RCC_HSI_ON;
  RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
  RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
  RCC_OscInitStruct.PLL.PLLMUL = RCC_PLL_MUL6;
  if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
  {
    Error_Handler();
  }
  /** Initializes the CPU, AHB and APB busses 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_DIV256;
  RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV2;
  RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;
 
  if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_0) != HAL_OK)
  {
    Error_Handler();
  }
}
 
/**
  * @brief DAC Initialization Function
  * @param None
  * @retval None
  */
static void MX_DAC_Init(void)
{
 
  /* USER CODE BEGIN DAC_Init 0 */
 
  /* USER CODE END DAC_Init 0 */
 
  DAC_ChannelConfTypeDef sConfig = {0};
 
  /* USER CODE BEGIN DAC_Init 1 */
 
  /* USER CODE END DAC_Init 1 */
  /** DAC Initialization 
  */
  hdac.Instance = DAC;
  if (HAL_DAC_Init(&hdac) != HAL_OK)
  {
    Error_Handler();
  }
  /** DAC channel OUT1 config 
  */
  sConfig.DAC_Trigger = DAC_TRIGGER_NONE;
  sConfig.DAC_OutputBuffer = DAC_OUTPUTBUFFER_ENABLE;
  if (HAL_DAC_ConfigChannel(&hdac, &sConfig, DAC_CHANNEL_1) != HAL_OK)
  {
    Error_Handler();
  }
  /* USER CODE BEGIN DAC_Init 2 */
 
  /* USER CODE END DAC_Init 2 */
 
}
 
/**
  * @brief TIM6 Initialization Function
  * @param None
  * @retval None
  */
static void MX_TIM6_Init(void)
{
 
  /* USER CODE BEGIN TIM6_Init 0 */
 
  /* USER CODE END TIM6_Init 0 */
 
  TIM_MasterConfigTypeDef sMasterConfig = {0};
 
  /* USER CODE BEGIN TIM6_Init 1 */
 
  /* USER CODE END TIM6_Init 1 */
  htim6.Instance = TIM6;
  htim6.Init.Prescaler = 0;
  htim6.Init.CounterMode = TIM_COUNTERMODE_UP;
  htim6.Init.Period = 32768;
  htim6.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_ENABLE;
  if (HAL_TIM_Base_Init(&htim6) != HAL_OK)
  {
    Error_Handler();
  }
  sMasterConfig.MasterOutputTrigger = TIM_TRGO_UPDATE;
  sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE;
  if (HAL_TIMEx_MasterConfigSynchronization(&htim6, &sMasterConfig) != HAL_OK)
  {
    Error_Handler();
  }
  /* USER CODE BEGIN TIM6_Init 2 */
 
  /* USER CODE END TIM6_Init 2 */
 
}
 
/** 
  * Enable DMA controller clock
  */
static void MX_DMA_Init(void) 
{
  /* DMA controller clock enable */
  __HAL_RCC_DMA2_CLK_ENABLE();
 
  /* DMA interrupt init */
  /* DMA2_Channel3_IRQn interrupt configuration */
  HAL_NVIC_SetPriority(DMA2_Channel3_IRQn, 0, 0);
  HAL_NVIC_EnableIRQ(DMA2_Channel3_IRQn);
 
}
 
/**
  * @brief GPIO Initialization Function
  * @param None
  * @retval None
  */
static void MX_GPIO_Init(void)
{
  GPIO_InitTypeDef GPIO_InitStruct = {0};
 
  /* GPIO Ports Clock Enable */
  __HAL_RCC_GPIOC_CLK_ENABLE();
  __HAL_RCC_GPIOF_CLK_ENABLE();
  __HAL_RCC_GPIOA_CLK_ENABLE();
  __HAL_RCC_GPIOE_CLK_ENABLE();
  __HAL_RCC_GPIOB_CLK_ENABLE();
 
  /*Configure GPIO pin Output Level */
  HAL_GPIO_WritePin(GPIOE, LD4_Pin|LD3_Pin|LD5_Pin|LD7_Pin 
                          |LD9_Pin|LD10_Pin|LD8_Pin|LD6_Pin, GPIO_PIN_RESET);
 
  /*Configure GPIO pin : B1_Pin */
  GPIO_InitStruct.Pin = B1_Pin;
  GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  HAL_GPIO_Init(B1_GPIO_Port, &GPIO_InitStruct);
 
  /*Configure GPIO pins : LD4_Pin LD3_Pin LD5_Pin LD7_Pin 
                           LD9_Pin LD10_Pin LD8_Pin LD6_Pin */
  GPIO_InitStruct.Pin = LD4_Pin|LD3_Pin|LD5_Pin|LD7_Pin 
                          |LD9_Pin|LD10_Pin|LD8_Pin|LD6_Pin;
  GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
  HAL_GPIO_Init(GPIOE, &GPIO_InitStruct);
 
}
 
/* 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 */
 
  /* 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(char *file, uint32_t line)
{ 
  /* USER CODE BEGIN 6 */
  /* User can add his own implementation to report the file name and line number,
     tex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */
  /* USER CODE END 6 */
}
#endif /* USE_FULL_ASSERT */
 
/************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/

Thanks!

[S.Ma]

Unless missing something, you need a trigger to click the transfer of one table element to the DAC.

For debug purpose, use the timer to generate a pulse on a channel pin, then connect it to the DAC trigger pin. This way, before you tune the timer pulse frequency, you can manually push each element of the table by controlling the DAC trigger pin with a jumper wire.

[c64]

That's a good idea. I did an even simpler test. I set the DAC trigger to be external:

sConfig.DAC_Trigger = DAC_TRIGGER_EXT_IT9;

assigned pin PB9 as the external DAC trig:

  /*Configure GPIO pin : PB9 */
  GPIO_InitStruct.Pin = GPIO_PIN_9;
  GPIO_InitStruct.Mode = GPIO_MODE_IT_RISING;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);

and enabled the external interrupts:

  /* EXTI interrupt init*/
  HAL_NVIC_SetPriority(EXTI9_5_IRQn, 0, 0);
  HAL_NVIC_EnableIRQ(EXTI9_5_IRQn);

Then I simply used a jumper wire attached to PB9 and tapped Vcc, but nothing happened out from the DAC output on PA4. So still no signal.

[S.Ma]

Test, write a new value in the DACDR after arming the trigger without dma enabked to check the edge will change the analog output. Sanity check

[c64]

Ok, so I hope I did what you suggested correctly by doing this:

  /* USER CODE BEGIN 2 */
  HAL_DAC_Start(&hdac,DAC_CHANNEL_1);
  //HAL_DAC_Start_DMA(&hdac, DAC_CHANNEL_1, (uint32_t*)sine_wave_array, 32, DAC_ALIGN_12B_R);
  HAL_DAC_SetValue(&hdac, DAC_CHANNEL_1, DAC_ALIGN_12B_R, (uint32_t*)2500);
  /* USER CODE END 2 */

That is, I commented out the DAC-DMA line, and manually set the DAC value. There is still no change in the PA4 output when I drive the PB9 pin high.

[c64]

I actually decided to start all over with the CubeMX design tool, and now it works perfectly when stepping through with external trigger (using a function generator with square wave output). Time to test with the internal timer.... Thank you for your help btw, I appreciate it.