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CAN communication not working

John_RENRUS
Associate II

‎2025-05-15 4:22 AM - last edited on ‎2025-05-15 7:24 AM by

Hello everyone,

I’m currently experiencing difficulties with setting up CAN communication on my STM32F4 microcontroller. Despite having configured the CAN interface and connecting it to a CAN transceiver, I observe no activity on my designated can_tx and can_rx pins. I have a second node connected for communication testing.

/* USER CODE BEGIN Header */
/**
  ******************************************************************************
  * @file           : main.c
  * @brief          : Main program body
  ******************************************************************************
  * @attention
  *
  * Copyright (c) 2025 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.
  *
  ******************************************************************************
  */
/* USER CODE END Header */
/* Includes ------------------------------------------------------------------*/
#include "main.h"
#include "usb_device.h"

/* Private includes ----------------------------------------------------------*/
/* USER CODE BEGIN Includes */
#include "stm32f4xx_hal_dac.h"
#include "stm32f4xx_hal_adc.h"
#include "usbd_cdc_if.h"
#include "stm32f4xx_hal_can.h"
/* USER CODE END Includes */

/* Private typedef -----------------------------------------------------------*/
/* USER CODE BEGIN PTD */

/* USER CODE END PTD */

/* Private define ------------------------------------------------------------*/
/* USER CODE BEGIN PD */

#define TRUE_THRESHOLD 0.4588235294117647  //(6,5V/42,5V)*3.0V ADC Schwellenwert nach Skalierung
#define ADC_VOLTAGE_FULL_SCALE 3.0 // Maximal erreichbare Spannung fuer ADC

// Am Anfang Ihres Programms im User Define Bereich
#define DAC_OUTPUT_VOLTAGE 0.4588235294117647 //(6,5V/42,5V)*3.0V oder welcher Wert gebraucht wird
#define DAC_VOLTAGE_FULL_SCALE 3.0 // oder welcher Wert gebraucht wird

/* USER CODE END PD */

/* Private macro -------------------------------------------------------------*/
/* USER CODE BEGIN PM */

/* USER CODE END PM */

/* Private variables ---------------------------------------------------------*/
ADC_HandleTypeDef hadc1;
ADC_HandleTypeDef hadc2;

CAN_HandleTypeDef hcan1;
CAN_HandleTypeDef hcan2;

DAC_HandleTypeDef hdac;

/* USER CODE BEGIN PV */
CAN_TxHeaderTypeDef myTxHeader;
uint8_t TxData[8];
uint32_t TxMailbox;
uint32_t adcValue1, adcValue2; 
/* USER CODE END PV */

/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_CAN1_Init(void);
static void MX_CAN2_Init(void);
static void MX_DAC_Init(void);
static void MX_ADC1_Init(void);
static void MX_ADC2_Init(void);
/* USER CODE BEGIN PFP */

void DAC_SetComparisonVoltage(void);
void ADC_Scan_RegularChannels(void);
void Send_CAN_Message(void);
void Send_USB_Data(void);
void ToggleErrorLED(uint8_t number_of_blinks);

/* 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_CAN1_Init();
  MX_CAN2_Init();
  MX_DAC_Init();
  MX_USB_DEVICE_Init();
  MX_ADC1_Init();
  MX_ADC2_Init();
  /* USER CODE BEGIN 2 */
  DAC_SetComparisonVoltage(); // Setze die Vergleichsspannung per DAC

  /* USER CODE END 2 */

  /* Infinite loop */
  /* USER CODE BEGIN WHILE */
  while (1)
  {
    /* USER CODE END WHILE */

    /* USER CODE BEGIN 3 */
ADC_Scan_RegularChannels(); // Lese ADC-Werte

    // ueberpruefe, ob die Spannung unter/ueber dem Schwellenwert ist
    if (adcValue1 > TRUE_THRESHOLD / ADC_VOLTAGE_FULL_SCALE * 4095)
    {
      HAL_GPIO_WritePin(GPIOD, GPIO_PIN_13, GPIO_PIN_SET); // Orange LED anschalten
    }
    else
    {
      HAL_GPIO_WritePin(GPIOD, GPIO_PIN_13, GPIO_PIN_RESET); // Orange LED ausschalten
    }

    Send_CAN_Message(); // Sende Nachricht über CAN

Send_USB_Data(); //test massage über usb

    HAL_Delay(50); // 1/50 Sekunde warten

  }
  /* USER CODE END 3 */
}
/**
  * @brief System Clock Configuration
  * @retval None
  */
void SystemClock_Config(void)
{
  RCC_OscInitTypeDef RCC_OscInitStruct = {0};
  RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};

  /** Configure the main internal regulator output voltage
  */
  __HAL_RCC_PWR_CLK_ENABLE();
  __HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE1);

  /** Initializes the RCC Oscillators according to the specified parameters
  * in the RCC_OscInitTypeDef structure.
  */
  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 = 4;
  RCC_OscInitStruct.PLL.PLLN = 168;
  RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV2;
  RCC_OscInitStruct.PLL.PLLQ = 7;
  if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
  {
    ToggleErrorLED(2); // Toggle LED zweimal für Fehler in SystemClock_Config
  }
  /** 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_DIV2;
  RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV2;
  RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV2;

  if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_2) != HAL_OK)
  {
    ToggleErrorLED(3); // Toggle LED dreimal für Fehler in der ClockConfig
  }
}
/**
  * @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 */

  /** Configure the global features of the ADC (Clock, Resolution, Data Alignment and number of conversion)
  */
  hadc1.Instance = ADC1;
  hadc1.Init.ClockPrescaler = ADC_CLOCK_SYNC_PCLK_DIV2;
  hadc1.Init.Resolution = ADC_RESOLUTION_12B;
  hadc1.Init.ScanConvMode = DISABLE;
  hadc1.Init.ContinuousConvMode = DISABLE;
  hadc1.Init.DiscontinuousConvMode = DISABLE;
  hadc1.Init.ExternalTrigConvEdge = ADC_EXTERNALTRIGCONVEDGE_NONE;
  hadc1.Init.ExternalTrigConv = ADC_SOFTWARE_START;
  hadc1.Init.DataAlign = ADC_DATAALIGN_RIGHT;
  hadc1.Init.NbrOfConversion = 1;
  hadc1.Init.DMAContinuousRequests = DISABLE;
  hadc1.Init.EOCSelection = ADC_EOC_SINGLE_CONV;
  if (HAL_ADC_Init(&hadc1) != HAL_OK)
  {
    ToggleErrorLED(4); // Toggle LED viermal für Fehler in ADC1_Init
  }
  /** Configure for the selected ADC regular channel its corresponding rank in the sequencer and its sample time.
  */
  sConfig.Channel = ADC_CHANNEL_1;
  sConfig.Rank = 1;
  sConfig.SamplingTime = ADC_SAMPLETIME_3CYCLES;
  if (HAL_ADC_ConfigChannel(&hadc1, &sConfig) != HAL_OK)
  {
    ToggleErrorLED(5); // Toggle LED fünfmal für Fehler bei der Kanal-Konfiguration
  }
}
/**
  * @brief ADC2 Initialization Function
  *  None
  * @retval None
  */
static void MX_ADC2_Init(void)
{

  /* USER CODE BEGIN ADC2_Init 0 */

  /* USER CODE END ADC2_Init 0 */

  ADC_ChannelConfTypeDef sConfig = {0};

  /* USER CODE BEGIN ADC2_Init 1 */

  /* USER CODE END ADC2_Init 1 */

  /** Configure the global features of the ADC (Clock, Resolution, Data Alignment and number of conversion)
  */
  hadc2.Instance = ADC2;
  hadc2.Init.ClockPrescaler = ADC_CLOCK_SYNC_PCLK_DIV2;
  hadc2.Init.Resolution = ADC_RESOLUTION_12B;
  hadc2.Init.ScanConvMode = DISABLE;
  hadc2.Init.ContinuousConvMode = DISABLE;
  hadc2.Init.DiscontinuousConvMode = DISABLE;
  hadc2.Init.ExternalTrigConvEdge = ADC_EXTERNALTRIGCONVEDGE_NONE;
  hadc2.Init.ExternalTrigConv = ADC_SOFTWARE_START;
  hadc2.Init.DataAlign = ADC_DATAALIGN_RIGHT;
  hadc2.Init.NbrOfConversion = 1;
  hadc2.Init.DMAContinuousRequests = DISABLE;
  hadc2.Init.EOCSelection = ADC_EOC_SINGLE_CONV;
  if (HAL_ADC_Init(&hadc2) != HAL_OK)
  {
    ToggleErrorLED(6); // Toggle LED sechsmal für Fehler in ADC2_Init
  }
  /** Configure for the selected ADC regular channel its corresponding rank in the sequencer and its sample time.
  */
  sConfig.Channel = ADC_CHANNEL_2;
  sConfig.Rank = 1;
  sConfig.SamplingTime = ADC_SAMPLETIME_3CYCLES;
  if (HAL_ADC_ConfigChannel(&hadc2, &sConfig) != HAL_OK)
  {
    ToggleErrorLED(7); // Toggle LED siebenmal für Fehler bei der Kanal-Konfiguration
  }
}
/**
  * @brief CAN1 Initialization Function
  *  None
  * @retval None
  */
static void MX_CAN1_Init(void)
{

  /* USER CODE BEGIN CAN1_Init 0 */

  /* USER CODE END CAN1_Init 0 */

  /* USER CODE BEGIN CAN1_Init 1 */

  /* USER CODE END CAN1_Init 1 */
  hcan1.Instance = CAN1;
  hcan1.Init.Prescaler = 6;
  hcan1.Init.Mode = CAN_MODE_NORMAL;
  hcan1.Init.SyncJumpWidth = CAN_SJW_1TQ;
  hcan1.Init.TimeSeg1 = CAN_BS1_11TQ;
  hcan1.Init.TimeSeg2 = CAN_BS2_2TQ;
  hcan1.Init.TimeTriggeredMode = DISABLE;
  hcan1.Init.AutoBusOff = DISABLE;
  hcan1.Init.AutoWakeUp = DISABLE;
  hcan1.Init.AutoRetransmission = ENABLE;
  hcan1.Init.ReceiveFifoLocked = DISABLE;
  hcan1.Init.TransmitFifoPriority = DISABLE;
  if (HAL_CAN_Init(&hcan1) != HAL_OK)
  {
    ToggleErrorLED(8); // Toggle LED achtmal für Fehler in CAN1_Init
  }
}
/**
  * @brief CAN2 Initialization Function
  *  None
  * @retval None
  */
static void MX_CAN2_Init(void)
{

  /* USER CODE BEGIN CAN2_Init 0 */

  /* USER CODE END CAN2_Init 0 */

  /* USER CODE BEGIN CAN2_Init 1 */

  /* USER CODE END CAN2_Init 1 */
  hcan2.Instance = CAN2;
  hcan2.Init.Prescaler = 6;
  hcan2.Init.Mode = CAN_MODE_NORMAL;
  hcan2.Init.SyncJumpWidth = CAN_SJW_1TQ;
  hcan2.Init.TimeSeg1 = CAN_BS1_11TQ;
  hcan2.Init.TimeSeg2 = CAN_BS2_2TQ;
  hcan2.Init.TimeTriggeredMode = DISABLE;
  hcan2.Init.AutoBusOff = DISABLE;
  hcan2.Init.AutoWakeUp = DISABLE;
  hcan2.Init.AutoRetransmission = ENABLE;
  hcan2.Init.ReceiveFifoLocked = DISABLE;
  hcan2.Init.TransmitFifoPriority = DISABLE;
  if (HAL_CAN_Init(&hcan2) != HAL_OK)
  {
    ToggleErrorLED(9); // Toggle LED neunmal für Fehler in CAN2_Init
  }
}
/**
  * @brief DAC Initialization Function
  *  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)
  {
    ToggleErrorLED(10); // Toggle LED zehnmal für Fehler in DAC_Init
  }
  /** 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)
  {
    ToggleErrorLED(11); // Toggle LED elfmal für Fehler bei der Kanal-Konfiguration
  }
}
/**
  * @brief GPIO Initialization Function
  *  None
  * @retval None
  */
static void MX_GPIO_Init(void)
{
  GPIO_InitTypeDef GPIO_InitStruct = {0};
  /* USER CODE BEGIN MX_GPIO_Init_1 */

  /* USER CODE END MX_GPIO_Init_1 */

  /* GPIO Ports Clock Enable */
  __HAL_RCC_GPIOH_CLK_ENABLE();
  __HAL_RCC_GPIOA_CLK_ENABLE();
  __HAL_RCC_GPIOB_CLK_ENABLE();
  __HAL_RCC_GPIOD_CLK_ENABLE();

  /*Configure GPIO pin Output Level */
  HAL_GPIO_WritePin(GPIOD, GPIO_PIN_12|GPIO_PIN_13|GPIO_PIN_14|GPIO_PIN_15, GPIO_PIN_RESET);

  /*Configure GPIO pin : PA0 */
  GPIO_InitStruct.Pin = GPIO_PIN_0;
  GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);

  /*Configure GPIO pins : PD12 PD13 PD14 PD15 */
  GPIO_InitStruct.Pin = GPIO_PIN_12|GPIO_PIN_13|GPIO_PIN_14|GPIO_PIN_15;
  GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
  HAL_GPIO_Init(GPIOD, &GPIO_InitStruct);

  /* USER CODE BEGIN MX_GPIO_Init_2 */

  /* USER CODE END MX_GPIO_Init_2 */
}
/* USER CODE BEGIN 4 */
void DAC_SetComparisonVoltage(void)
{
  HAL_DAC_Start(&hdac, DAC_CHANNEL_1);
  HAL_DAC_SetValue(&hdac, DAC_CHANNEL_1, DAC_ALIGN_12B_R, (uint32_t)(DAC_OUTPUT_VOLTAGE / DAC_VOLTAGE_FULL_SCALE * 4095));
}
void ADC_Scan_RegularChannels(void)
{
  HAL_ADC_Start(&hadc1); 
  if (HAL_ADC_PollForConversion(&hadc1, 100) == HAL_OK)
  {
    adcValue1 = HAL_ADC_GetValue(&hadc1); 
  }
  
  HAL_ADC_Start(&hadc2); 
  if (HAL_ADC_PollForConversion(&hadc2, 100) == HAL_OK)
  {
    adcValue2 = HAL_ADC_GetValue(&hadc2);
  }
}
unsigned int value = 0; 
void Send_CAN_Message(void)
{

  myTxHeader.StdId = 0x321;
  myTxHeader.ExtId = 0x00;
  myTxHeader.RTR = CAN_RTR_DATA;
  myTxHeader.IDE = CAN_ID_STD;
  myTxHeader.DLC = 8;
  myTxHeader.TransmitGlobalTime = DISABLE;

value = HAL_CAN_AddTxMessage(&hcan1, &myTxHeader, TxData, &TxMailbox);

if (value != HAL_OK)
{
ToggleErrorLED(2); // Toggle LED zwölfmal für Fehler bei Send_CAN_Message
}
}
/* Beispiel: Senden einer Testnachricht ueber USB CDC */
void Send_USB_Data(void) {
    HAL_GPIO_TogglePin(GPIOD, GPIO_PIN_15); // Toggle der blauen LED
    
    // Berechnung des Spannungswertes
    uint32_t adcValue = adcValue1; 
    float voltageMeasured = (adcValue / 4095.0) * 3.0; // Skalierung für 3.0V statt 3.3V, auf die Hardware anpassen
    
    // Offset-Korrektur basierend auf Beobachtungen
    float offsetCorrection = 0.0;

    // Anpassen des Offsets basierend auf gemessener Spannung
    if (voltageMeasured < 1.0) {
        offsetCorrection = 0.030 * voltageMeasured; // zu niedrige Werte offset-Korrektur
    } else if (voltageMeasured < 2.0) {
        offsetCorrection = 0.025 * voltageMeasured; // mittlere Werte offset-Korrektur
    } else {
        offsetCorrection = 0.022 * voltageMeasured; // höhere Werte offset-Korrektur
    }

    // Endgültige Korrektur der Messspannung
    float correctedVoltage = voltageMeasured - offsetCorrection; 

    // Berechnung der tatsächlichen Spannung, basierend auf Spannungsteiler
    float actualVoltage = (correctedVoltage / 3.0) * 42.5;

    // Holen Sie sich den aktuellen Zeitstempel
    uint32_t timestamp = HAL_GetTick();

    // Formatieren Sie die Nachricht im CSV-Format
    char message[50];
    snprintf(message, sizeof(message), "%u, %.4f\n", timestamp, actualVoltage);

    // Senden Sie die formatierte Nachricht über USB
    CDC_Transmit_FS((uint8_t*)message, strlen(message));

    
}
void ToggleErrorLED(uint8_t number_of_blinks)
{
    for(uint8_t i = 0; i < number_of_blinks * 2; i++) // Immer gerade Anzahl, um LED zurückzusetzen
    {
        HAL_GPIO_TogglePin(GPIOD, GPIO_PIN_12);
        HAL_Delay(400);
    }
}
/* 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 */
  // HAL_GPIO_TogglePin(GPIOD, GPIO_PIN_12); // Fehleranzeige auch hier
  __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 */
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Edited to apply code formatting - please see How to insert source code for future reference.

Labels:
0 Kudos
11 REPLIES 11
Billy OWEN
ST Employee

‎2025-05-27 9:20 AM

Hi @John_RENRUS 

 

This post has been escalated to the ST Online Support Team for additional assistance.  We'll contact you directly.

 

Regards,

Billy

0 Kudos
Karl Yamashita
Principal

‎2025-05-27 1:10 PM

I've looked at your code and I see you're missing some function calls

  • HAL_CAN_ConfigFilter
  • HAL_CAN_Start
  • HAL_CAN_ActivateNotification
/*
function: Set CAN filter to pass all ID's
input: hcan instance
output: none
*/
void CAN_SetFilter(CAN_HandleTypeDef *hcan)
{
	static CAN_FilterTypeDef sFilterConfig;

	if(hcan == &hcan1)
	{
		sFilterConfig.FilterBank = 0;
	}
#ifdef HCAN2
	else if(hcan == &hcan2)
	{
		sFilterConfig.FilterBank = 14;
	}
#endif

	sFilterConfig.FilterMode             = CAN_FILTERMODE_IDMASK;
	sFilterConfig.FilterScale            = CAN_FILTERSCALE_32BIT;
	sFilterConfig.FilterIdHigh           = 0x0000;
	sFilterConfig.FilterIdLow            = 0x0000;
	sFilterConfig.FilterMaskIdHigh       = 0x0000;
	sFilterConfig.FilterMaskIdLow        = 0x0000;
	sFilterConfig.FilterFIFOAssignment   = CAN_FILTER_FIFO0;
	sFilterConfig.FilterActivation       = ENABLE;

	if(HAL_CAN_ConfigFilter(hcan, &sFilterConfig) != HAL_OK)
	{
		Error_Handler();
	}
	if(HAL_CAN_Start(hcan) != HAL_OK)
	{
		Error_Handler();
	}
	if (HAL_CAN_ActivateNotification(hcan, CAN_IT_RX_FIFO0_MSG_PENDING | CAN_IT_TX_MAILBOX_EMPTY ) != HAL_OK) // enables CAN notification.
	{
		Error_Handler();
	}
}
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