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Stm325
Graduate II
March 11, 2025
Question

Sending ADC data directly over UART via DMA

  • March 11, 2025
  • 2 replies
  • 846 views

Hi, I am trying to sample ADC data with stm32l4s5 using b-l4s5-iot01a board. I enabled ADC, USART1 and DMA on both but I do not see anything on my serial terminal. I am trying to send it over st-link connection, I sent a sample text like "Hello" and it worked so usart configuration must be right other than DMA. I appreciate any advice.

This is my code:

 

#include "main.h"

/* Private includes ----------------------------------------------------------*/
/* USER CODE BEGIN Includes */
//#include "stm32l4s5i_iot01.h"
#include "math.h"
#include "stdio.h"
/* 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 ---------------------------------------------------------*/
ADC_HandleTypeDef hadc1;
DMA_HandleTypeDef hdma_adc1;

TIM_HandleTypeDef htim1;
TIM_HandleTypeDef htim3;
TIM_HandleTypeDef htim15;

UART_HandleTypeDef huart1;
DMA_HandleTypeDef hdma_usart1_tx;

/* USER CODE BEGIN PV */

/* 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_TIM1_Init(void);
static void MX_TIM3_Init(void);
static void MX_TIM15_Init(void);
static void MX_ADC1_Init(void);
static void MX_USART1_UART_Init(void);
/* USER CODE BEGIN PFP */

/* USER CODE END PFP */

/* Private user code ---------------------------------------------------------*/
/* USER CODE BEGIN 0 */

void delay_us (uint16_t us);

uint32_t value_adc;
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 */
 //BSP_LED_Init(LED2);
 /* 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_TIM1_Init();
 MX_TIM3_Init();
 MX_TIM15_Init();
 MX_ADC1_Init();
 MX_USART1_UART_Init();
 /* USER CODE BEGIN 2 */
 HAL_TIM_Base_Start(&htim1);
 HAL_TIM_Base_Start(&htim3);

HAL_TIM_OnePulse_Start(&htim15, TIM_CHANNEL_1);
 HAL_ADCEx_Calibration_Start(&hadc1, ADC_SINGLE_ENDED);
 HAL_ADC_Start_DMA(&hadc1,(uint32_t*)&value_adc,1);
 HAL_UART_Transmit_DMA(&huart1, value_adc, sizeof(value_adc));
while (1)
 {
}
}
void SystemClock_Config(void)
{
 RCC_OscInitTypeDef RCC_OscInitStruct = {0};
 RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};

 /** Configure the main internal regulator output voltage
 */
 if (HAL_PWREx_ControlVoltageScaling(PWR_REGULATOR_VOLTAGE_SCALE1_BOOST) != HAL_OK)
 {
 Error_Handler();
 }

 /** Initializes the RCC Oscillators according to the specified parameters
 * in the RCC_OscInitTypeDef structure.
 */
 RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_MSI;
 RCC_OscInitStruct.MSIState = RCC_MSI_ON;
 RCC_OscInitStruct.MSICalibrationValue = 0;
 RCC_OscInitStruct.MSIClockRange = RCC_MSIRANGE_6;
 RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
 RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_MSI;
 RCC_OscInitStruct.PLL.PLLM = 1;
 RCC_OscInitStruct.PLL.PLLN = 60;
 RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV2;
 RCC_OscInitStruct.PLL.PLLQ = RCC_PLLQ_DIV2;
 RCC_OscInitStruct.PLL.PLLR = RCC_PLLR_DIV2;
 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_DIV1;
 RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;

 if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_5) != HAL_OK)
 {
 Error_Handler();
 }
}

/**
 * @brief ADC1 Initialization Function
 * None
 * @retval None
 */
static void MX_ADC1_Init(void)
{

 /* USER CODE BEGIN ADC1_Init 0 */

 /* USER CODE END ADC1_Init 0 */

 ADC_ChannelConfTypeDef sConfig = {0};

 /* USER CODE BEGIN ADC1_Init 1 */

 /* USER CODE END ADC1_Init 1 */

 /** Common config
 */
 hadc1.Instance = ADC1;
 hadc1.Init.ClockPrescaler = ADC_CLOCK_ASYNC_DIV2;
 hadc1.Init.Resolution = ADC_RESOLUTION_8B;
 hadc1.Init.DataAlign = ADC_DATAALIGN_RIGHT;
 hadc1.Init.ScanConvMode = ADC_SCAN_DISABLE;
 hadc1.Init.EOCSelection = ADC_EOC_SINGLE_CONV;
 hadc1.Init.LowPowerAutoWait = DISABLE;
 hadc1.Init.ContinuousConvMode = ENABLE;
 hadc1.Init.NbrOfConversion = 1;
 hadc1.Init.DiscontinuousConvMode = DISABLE;
 hadc1.Init.ExternalTrigConv = ADC_SOFTWARE_START;
 hadc1.Init.ExternalTrigConvEdge = ADC_EXTERNALTRIGCONVEDGE_NONE;
 hadc1.Init.DMAContinuousRequests = ENABLE;
 hadc1.Init.Overrun = ADC_OVR_DATA_PRESERVED;
 hadc1.Init.OversamplingMode = DISABLE;
 if (HAL_ADC_Init(&hadc1) != HAL_OK)
 {
 Error_Handler();
 }

 /** Configure Regular Channel
 */
 sConfig.Channel = ADC_CHANNEL_1;
 sConfig.Rank = ADC_REGULAR_RANK_1;
 sConfig.SamplingTime = ADC_SAMPLETIME_2CYCLES_5;
 sConfig.SingleDiff = ADC_SINGLE_ENDED;
 sConfig.OffsetNumber = ADC_OFFSET_NONE;
 sConfig.Offset = 0;
 if (HAL_ADC_ConfigChannel(&hadc1, &sConfig) != HAL_OK)
 {
 Error_Handler();
 }
 /* USER CODE BEGIN ADC1_Init 2 */

 /* USER CODE END ADC1_Init 2 */

}

/**
 * @brief TIM1 Initialization Function
 * None
 * @retval None
 */
static void MX_TIM1_Init(void)
{

 /* USER CODE BEGIN TIM1_Init 0 */

 /* USER CODE END TIM1_Init 0 */

 TIM_ClockConfigTypeDef sClockSourceConfig = {0};
 TIM_MasterConfigTypeDef sMasterConfig = {0};

 /* USER CODE BEGIN TIM1_Init 1 */

 /* USER CODE END TIM1_Init 1 */
 htim1.Instance = TIM1;
 htim1.Init.Prescaler = 0;
 htim1.Init.CounterMode = TIM_COUNTERMODE_UP;
 htim1.Init.Period = 65535;
 htim1.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
 htim1.Init.RepetitionCounter = 0;
 htim1.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_DISABLE;
 if (HAL_TIM_Base_Init(&htim1) != HAL_OK)
 {
 Error_Handler();
 }
 sClockSourceConfig.ClockSource = TIM_CLOCKSOURCE_INTERNAL;
 if (HAL_TIM_ConfigClockSource(&htim1, &sClockSourceConfig) != HAL_OK)
 {
 Error_Handler();
 }
 sMasterConfig.MasterOutputTrigger = TIM_TRGO_RESET;
 sMasterConfig.MasterOutputTrigger2 = TIM_TRGO2_RESET;
 sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE;
 if (HAL_TIMEx_MasterConfigSynchronization(&htim1, &sMasterConfig) != HAL_OK)
 {
 Error_Handler();
 }
 /* USER CODE BEGIN TIM1_Init 2 */

 /* USER CODE END TIM1_Init 2 */

}

/**
 * @brief TIM3 Initialization Function
 * None
 * @retval None
 */
static void MX_TIM3_Init(void)
{

 /* USER CODE BEGIN TIM3_Init 0 */

 /* USER CODE END TIM3_Init 0 */

 TIM_ClockConfigTypeDef sClockSourceConfig = {0};
 TIM_MasterConfigTypeDef sMasterConfig = {0};

 /* USER CODE BEGIN TIM3_Init 1 */

 /* USER CODE END TIM3_Init 1 */
 htim3.Instance = TIM3;
 htim3.Init.Prescaler = 12000-1;
 htim3.Init.CounterMode = TIM_COUNTERMODE_UP;
 htim3.Init.Period = 100-1;
 htim3.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
 htim3.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_DISABLE;
 if (HAL_TIM_Base_Init(&htim3) != HAL_OK)
 {
 Error_Handler();
 }
 sClockSourceConfig.ClockSource = TIM_CLOCKSOURCE_INTERNAL;
 if (HAL_TIM_ConfigClockSource(&htim3, &sClockSourceConfig) != HAL_OK)
 {
 Error_Handler();
 }
 sMasterConfig.MasterOutputTrigger = TIM_TRGO_UPDATE;
 sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE;
 if (HAL_TIMEx_MasterConfigSynchronization(&htim3, &sMasterConfig) != HAL_OK)
 {
 Error_Handler();
 }
 /* USER CODE BEGIN TIM3_Init 2 */

 /* USER CODE END TIM3_Init 2 */

}

/**
 * @brief TIM15 Initialization Function
 * None
 * @retval None
 */
static void MX_TIM15_Init(void)
{

 /* USER CODE BEGIN TIM15_Init 0 */

 /* USER CODE END TIM15_Init 0 */

 TIM_SlaveConfigTypeDef sSlaveConfig = {0};
 TIM_MasterConfigTypeDef sMasterConfig = {0};
 TIM_OC_InitTypeDef sConfigOC = {0};
 TIM_BreakDeadTimeConfigTypeDef sBreakDeadTimeConfig = {0};

 /* USER CODE BEGIN TIM15_Init 1 */

 /* USER CODE END TIM15_Init 1 */
 htim15.Instance = TIM15;
 htim15.Init.Prescaler = 10-1;
 htim15.Init.CounterMode = TIM_COUNTERMODE_UP;
 htim15.Init.Period = 6-1;
 htim15.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
 htim15.Init.RepetitionCounter = 3-1;
 htim15.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_DISABLE;
 if (HAL_TIM_Base_Init(&htim15) != HAL_OK)
 {
 Error_Handler();
 }
 if (HAL_TIM_PWM_Init(&htim15) != HAL_OK)
 {
 Error_Handler();
 }
 if (HAL_TIM_OnePulse_Init(&htim15, TIM_OPMODE_SINGLE) != HAL_OK)
 {
 Error_Handler();
 }
 sSlaveConfig.SlaveMode = TIM_SLAVEMODE_TRIGGER;
 sSlaveConfig.InputTrigger = TIM_TS_ITR1;
 if (HAL_TIM_SlaveConfigSynchro(&htim15, &sSlaveConfig) != HAL_OK)
 {
 Error_Handler();
 }
 sMasterConfig.MasterOutputTrigger = TIM_TRGO_UPDATE;
 sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE;
 if (HAL_TIMEx_MasterConfigSynchronization(&htim15, &sMasterConfig) != HAL_OK)
 {
 Error_Handler();
 }
 sConfigOC.OCMode = TIM_OCMODE_PWM2;
 sConfigOC.Pulse = 3;
 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_PWM_ConfigChannel(&htim15, &sConfigOC, TIM_CHANNEL_1) != HAL_OK)
 {
 Error_Handler();
 }
 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.AutomaticOutput = TIM_AUTOMATICOUTPUT_DISABLE;
 if (HAL_TIMEx_ConfigBreakDeadTime(&htim15, &sBreakDeadTimeConfig) != HAL_OK)
 {
 Error_Handler();
 }
 /* USER CODE BEGIN TIM15_Init 2 */

 /* USER CODE END TIM15_Init 2 */
 HAL_TIM_MspPostInit(&htim15);

}

/**
 * @brief USART1 Initialization Function
 * None
 * @retval None
 */
static void MX_USART1_UART_Init(void)
{

 /* USER CODE BEGIN USART1_Init 0 */

 /* USER CODE END USART1_Init 0 */

 /* USER CODE BEGIN USART1_Init 1 */

 /* USER CODE END USART1_Init 1 */
 huart1.Instance = USART1;
 huart1.Init.BaudRate = 115200;
 huart1.Init.WordLength = UART_WORDLENGTH_8B;
 huart1.Init.StopBits = UART_STOPBITS_1;
 huart1.Init.Parity = UART_PARITY_NONE;
 huart1.Init.Mode = UART_MODE_TX;
 huart1.Init.HwFlowCtl = UART_HWCONTROL_NONE;
 huart1.Init.OverSampling = UART_OVERSAMPLING_16;
 huart1.Init.OneBitSampling = UART_ONE_BIT_SAMPLE_DISABLE;
 huart1.Init.ClockPrescaler = UART_PRESCALER_DIV1;
 huart1.AdvancedInit.AdvFeatureInit = UART_ADVFEATURE_NO_INIT;
 if (HAL_UART_Init(&huart1) != HAL_OK)
 {
 Error_Handler();
 }
 if (HAL_UARTEx_SetTxFifoThreshold(&huart1, UART_TXFIFO_THRESHOLD_1_8) != HAL_OK)
 {
 Error_Handler();
 }
 if (HAL_UARTEx_SetRxFifoThreshold(&huart1, UART_RXFIFO_THRESHOLD_1_8) != HAL_OK)
 {
 Error_Handler();
 }
 if (HAL_UARTEx_DisableFifoMode(&huart1) != HAL_OK)
 {
 Error_Handler();
 }
 /* USER CODE BEGIN USART1_Init 2 */

 /* USER CODE END USART1_Init 2 */

}

/**
 * Enable DMA controller clock
 */
static void MX_DMA_Init(void)
{

 /* DMA controller clock enable */
 __HAL_RCC_DMAMUX1_CLK_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);
 /* DMA1_Channel4_IRQn interrupt configuration */
 HAL_NVIC_SetPriority(DMA1_Channel4_IRQn, 0, 0);
 HAL_NVIC_EnableIRQ(DMA1_Channel4_IRQn);

}

/**
 * @brief GPIO Initialization Function
 * 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_GPIOC_CLK_ENABLE();
 __HAL_RCC_GPIOA_CLK_ENABLE();
 __HAL_RCC_GPIOB_CLK_ENABLE();

/* USER CODE BEGIN MX_GPIO_Init_2 */
/* USER CODE END MX_GPIO_Init_2 */
}

/* USER CODE BEGIN 4 */
void delay_us (uint16_t us)
{
	__HAL_TIM_SET_COUNTER(&htim1,0); // set the counter value a 0
	while (__HAL_TIM_GET_COUNTER(&htim1) < us); // wait for the counter to reach the us input in the parameter
}



/* 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.
 * file: pointer to the source file name
 * 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 */

 

 

Stm325_0-1741722104329.pngStm325_1-1741722114771.pngStm325_2-1741722126571.pngAnd these are the ADC and USART configurations

Stm325_3-1741722148640.png

 

    This topic has been closed for replies.

    2 replies

    A
    Andrew Neil
    Super User
    March 11, 2025

    Did you try sending the ADC data without DMA ?

    S
    Stm325Author
    Graduate II
    March 11, 2025

    No but I want to achieve the highest sampling rate as possible so I thought using DMA would be better

    A
    Andrew Neil
    Super User
    March 11, 2025

    Do just one step at a time!

    T
    TDK
    Super User
    March 11, 2025

    Wait until the data is there before you send it. The ADC DMA operation happens asynchronously.

    Your terminal program is probably set up to receive text, not raw data, and may silently ignore non-ASCII characters like 0.

    Data is a uint16_t, not uint32_t.

     

      S
      Stm325Author
      Graduate II
      March 11, 2025
      void HAL_ADC_ConvCpltCallback(ADC_HandleTypeDef* hadc)
{
 if (hadc->Instance == ADC1)
 {
 char str_adc[10];
 sprintf(str_adc, "%lu\n", value_adc);
 HAL_UART_Transmit_DMA(&huart1, (uint8_t*)str_adc, strlen(str_adc));
 }
}

      I added this callback to convert it to string. Also the program looks like it is stuck at HAL_ADC_Start_DMA(&hadc1, &value_adc, 1); couldnt figure out why 

      P
      psabela
      Visitor II
      March 17, 2025

      Check if the overwrite flag is set as possible cause why ADC is stuck.  You may try setting overrun behavior to overwrite. 

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