Creating a CANopen Protocol

[kyruss_21]

I'm creating a CANopen protocol, but I'm having a problem with the code. I used two while loops, and as far as I understand, this is preventing me from seeing the data I'm getting from the sensor in the 'live expression' section. Do you have any suggestions?

/* USER CODE BEGIN Header */
/**
  ******************************************************************************
  * @file           : main.c
  * @brief          : Main program body
  ******************************************************************************
  * @attention
  *
  * Copyright (c) 2026 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"

/* Private includes ----------------------------------------------------------*/
/* USER CODE BEGIN Includes */
#include <math.h>
/* USER CODE END Includes */

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

/* USER CODE END PTD */

/* Private define ------------------------------------------------------------*/
/* USER CODE BEGIN PD */
#define KEY_PRESSED     GPIO_PIN_RESET
#define KEY_NOT_PRESSED GPIO_PIN_SET
/* USER CODE END PD */

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

/* Private variables ---------------------------------------------------------*/
ADC_HandleTypeDef hadc1;
DMA_HandleTypeDef hdma_adc1;

FDCAN_HandleTypeDef hfdcan1;

TIM_HandleTypeDef htim16;

/* USER CODE BEGIN PV */

FDCAN_TxHeaderTypeDef TxTransmitter; // TxTransmitter Structure'ı
FDCAN_RxHeaderTypeDef rxHeader;      // Ortak RX okuma başlığı

uint32_t verici_bilgileri[5];

// LIVE EXPRESSIONS İÇİN VOLATILE EKLENDİ
volatile uint32_t ADC[3];
volatile uint8_t temp1, temp2, temp3;
volatile uint8_t istenilen_sicaklik[8];
volatile uint8_t sayac = 0;
volatile uint8_t start = 0;

uint8_t tx_buffer[8];
uint8_t heartbeat[2];
uint8_t NodeID = 1;
uint8_t rxData[8]; // Gelen mesajları tutacağımız ortak buffer

/* 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_ADC1_Init(void);
static void MX_FDCAN1_Init(void);
static void MX_TIM16_Init(void);
/* USER CODE BEGIN PFP */
void systemReset(void);
double Thermistor(int analogValue);
/* USER CODE END PFP */

/* Private user code ---------------------------------------------------------*/
/* USER CODE BEGIN 0 */
void HAL_TIM_PeriodElapsedCallback(TIM_HandleTypeDef *htim)
{
    if (htim == &htim16)
    {
        while (HAL_FDCAN_GetRxFifoFillLevel(&hfdcan1, FDCAN_RX_FIFO0) > 0)
        {
            // Mesajı kuyruktan bir kez okuyoruz
            if (HAL_FDCAN_GetRxMessage(&hfdcan1, FDCAN_RX_FIFO0, &rxHeader, rxData) == HAL_OK)
            {
                /* --- NMT MESAJI KONTROLÜ (ID: 0x00) --- */
                if (rxHeader.Identifier == 0x00 && rxHeader.DataLength == FDCAN_DLC_BYTES_2)
                {
                    switch (rxData[0])
                    {
                        case 0x01:   // Start
                            HAL_ADC_Start_DMA(&hadc1, (uint32_t*)ADC, 3); // &ADC hatası düzeltildi
                            start = 1;
                            break;
                        case 0x02:   // Stop
                            HAL_ADC_Stop_DMA(&hadc1);
                            start = 0;
                            break;
                        case 0x81:   // Reset Node
                            systemReset();
                            break;
                    }
                }
                
                /* Sistem Start edildiyse diğer komutları dinle */
                if (start == 1)
                {
                    /* --- RPDO KONTROLÜ (Örn ID: 0x201) --- */
                    if (rxHeader.Identifier == 0x201)
                    {
                        // RPDO ile gelen ilk byte istenilen sıcaklık
                        istenilen_sicaklik[0] = rxData[0]; 
                        
                        if (temp1 >= istenilen_sicaklik[0] || temp2 >= istenilen_sicaklik[0] || temp3 >= istenilen_sicaklik[0])
                        {
                            HAL_GPIO_WritePin(GPIOA, GPIO_PIN_5, SET);
                        }
                        else
                        {
                            HAL_GPIO_WritePin(GPIOA, GPIO_PIN_5, RESET);
                        }
                    }
                    /* --- SDO KONTROLÜ (Örn ID: 0x601) --- */
                    else if (rxHeader.Identifier == 0x601)
                    {
                        // 1. OKUMA İSTEĞİ (0x20 ---> SENSÖR VERİLERİ)
                        if (rxData[3] == 0x04 && rxData[4] == 0x20)
                        {
                            TxTransmitter.Identifier = 0x581;
                            TxTransmitter.IdType = FDCAN_STANDARD_ID;
                            TxTransmitter.TxFrameType = FDCAN_DATA_FRAME;
                            TxTransmitter.DataLength = FDCAN_DLC_BYTES_8;
                            TxTransmitter.ErrorStateIndicator = FDCAN_ESI_ACTIVE;
                            TxTransmitter.BitRateSwitch = FDCAN_BRS_OFF;
                            TxTransmitter.FDFormat = FDCAN_CLASSIC_CAN;
                            TxTransmitter.TxEventFifoControl = FDCAN_NO_TX_EVENTS;
                            TxTransmitter.MessageMarker = 0;

                            tx_buffer[0] = temp1;
                            tx_buffer[1] = temp2;
                            tx_buffer[2] = temp3;
                            tx_buffer[3] = 0;
                            tx_buffer[4] = 0;
                            tx_buffer[5] = 0;
                            tx_buffer[6] = 0;
                            tx_buffer[7] = 0;

                            HAL_FDCAN_AddMessageToTxFifoQ(&hfdcan1, &TxTransmitter, tx_buffer);
                        }
                        // 2. DİĞER OKUMA İSTEĞİ (0x21 ---> İSTENİLEN SICAKLIK DEĞERİ VERİSİ)
                        else if (rxData[3] == 0x04 && rxData[4] == 0x21)
                        {
                            TxTransmitter.Identifier = 0x581;
                            TxTransmitter.IdType = FDCAN_STANDARD_ID;
                            TxTransmitter.TxFrameType = FDCAN_DATA_FRAME;
                            TxTransmitter.DataLength = FDCAN_DLC_BYTES_8;
                            TxTransmitter.ErrorStateIndicator = FDCAN_ESI_ACTIVE;
                            TxTransmitter.BitRateSwitch = FDCAN_BRS_OFF;
                            TxTransmitter.FDFormat = FDCAN_CLASSIC_CAN;
                            TxTransmitter.TxEventFifoControl = FDCAN_NO_TX_EVENTS;
                            TxTransmitter.MessageMarker = 0;

                            tx_buffer[0] = istenilen_sicaklik[0];
                            tx_buffer[1] = 0;
                            tx_buffer[2] = 0;
                            tx_buffer[3] = 0;
                            tx_buffer[4] = 0;
                            tx_buffer[5] = 0;
                            tx_buffer[6] = 0;
                            tx_buffer[7] = 0;

                            HAL_FDCAN_AddMessageToTxFifoQ(&hfdcan1, &TxTransmitter, tx_buffer);
                        }
                        // 3. YAZMA/DEĞİŞTİRME İSTEĞİ (0x22)
                        else if (rxData[3] == 0x04 && rxData[4] == 0x22)
                        {
                            istenilen_sicaklik[0] = rxData[5];

                            // Veriyi başarıyla aldım ve güncelledim (ACK)
                            TxTransmitter.Identifier = 0x601;
                            TxTransmitter.IdType = FDCAN_STANDARD_ID;
                            TxTransmitter.TxFrameType = FDCAN_DATA_FRAME;
                            TxTransmitter.DataLength = FDCAN_DLC_BYTES_8;
                            TxTransmitter.ErrorStateIndicator = FDCAN_ESI_ACTIVE;
                            TxTransmitter.BitRateSwitch = FDCAN_BRS_OFF;
                            TxTransmitter.FDFormat = FDCAN_CLASSIC_CAN;
                            TxTransmitter.TxEventFifoControl = FDCAN_NO_TX_EVENTS;
                            TxTransmitter.MessageMarker = 0;

                            tx_buffer[0] = 0x60; // CANopen SDO Success
                            tx_buffer[1] = 0;
                            tx_buffer[2] = 0;
                            tx_buffer[3] = 0;
                            tx_buffer[4] = 0;
                            tx_buffer[5] = 0;
                            tx_buffer[6] = 0;
                            tx_buffer[7] = 0;

                            HAL_FDCAN_AddMessageToTxFifoQ(&hfdcan1, &TxTransmitter, tx_buffer);
                        }
                    }
                }
            }
        } // RX okuma bloğu bitti

        sayac++;
        if (sayac >= 10) // sayac==10 yerine güvenli olması için >= yapıldı
        {
            if (start == 1)
            {
                /*------HeartBeat-------*/
                TxTransmitter.Identifier = 0x701;
                TxTransmitter.IdType = FDCAN_STANDARD_ID;
                TxTransmitter.TxFrameType = FDCAN_DATA_FRAME;
                TxTransmitter.DataLength = FDCAN_DLC_BYTES_2;
                TxTransmitter.ErrorStateIndicator = FDCAN_ESI_ACTIVE;
                TxTransmitter.BitRateSwitch = FDCAN_BRS_OFF;
                TxTransmitter.FDFormat = FDCAN_CLASSIC_CAN;
                TxTransmitter.TxEventFifoControl = FDCAN_NO_TX_EVENTS;
                TxTransmitter.MessageMarker = 0;

                heartbeat[0] = 0x5F;
                heartbeat[1] = 0x7F;

                HAL_FDCAN_AddMessageToTxFifoQ(&hfdcan1, &TxTransmitter, heartbeat);

                /*------TPDO-------*/
                TxTransmitter.Identifier = 0x181;
                TxTransmitter.IdType = FDCAN_STANDARD_ID;
                TxTransmitter.TxFrameType = FDCAN_DATA_FRAME;
                TxTransmitter.DataLength = FDCAN_DLC_BYTES_8;
                TxTransmitter.ErrorStateIndicator = FDCAN_ESI_ACTIVE;
                TxTransmitter.BitRateSwitch = FDCAN_BRS_OFF;
                TxTransmitter.FDFormat = FDCAN_CLASSIC_CAN;
                TxTransmitter.TxEventFifoControl = FDCAN_NO_TX_EVENTS;
                TxTransmitter.MessageMarker = 0;

                tx_buffer[0] = temp1;
                tx_buffer[1] = temp2;
                tx_buffer[2] = temp3;
                tx_buffer[3] = 0;
                tx_buffer[4] = 0;
                tx_buffer[5] = 0;
                tx_buffer[6] = 0;
                tx_buffer[7] = 0;

                HAL_FDCAN_AddMessageToTxFifoQ(&hfdcan1, &TxTransmitter, tx_buffer);
            }
            sayac = 0;
        }
    }
}

void systemReset(void)
{
    NVIC_SystemReset();
}

double Thermistor(int analogValue)
{
    // Cihaz kısa devre veya kopuksa (0 veya çok yüksek değerler) formüle sokma
    if (analogValue > 0 && analogValue < 4095)
    {
        double temperature;
        temperature = log(((40950000.0 / analogValue) - 10000.0)); // Matematiksel hassasiyet düzeltildi (.0)
        temperature = 1.0 / (0.001129148 + (0.000234125 + (0.0000000876741 * temperature * temperature)) * temperature);
        temperature = temperature - 273.15;
        return temperature;
    }
    return 0.0; // Güvenli varsayılan değer
}

/* 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_ADC1_Init();
  MX_FDCAN1_Init();
  MX_TIM16_Init();
  /* USER CODE BEGIN 2 */
  
  // ÇOK ÖNEMLİ: ADC Kalibrasyonu olmadan DMA doğru okuma yapmaz.
  HAL_ADCEx_Calibration_Start(&hadc1, ADC_SINGLE_ENDED);

  HAL_FDCAN_Start(&hfdcan1);
  HAL_TIM_Base_Start_IT(&htim16);

  /* USER CODE END 2 */

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

      /* USER CODE BEGIN 3 */

      /*---------NTC VERİLERİNİN CELCİUS'A DÖNÜŞÜMÜ---------*/
      temp1 = (uint8_t)Thermistor(ADC[0]);
      temp2 = (uint8_t)Thermistor(ADC[1]);
      temp3 = (uint8_t)Thermistor(ADC[2]);

      /* 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_PWREx_ControlVoltageScaling(PWR_REGULATOR_VOLTAGE_SCALE1_BOOST);

  /** 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.PLLM = RCC_PLLM_DIV4;
  RCC_OscInitStruct.PLL.PLLN = 85;
  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_4) != HAL_OK)
  {
    Error_Handler();
  }
}

/**
  * @brief ADC1 Initialization Function
  *  None
  * @retval None
  */
static void MX_ADC1_Init(void)
{
  ADC_MultiModeTypeDef multimode = {0};
  ADC_ChannelConfTypeDef sConfig = {0};

  hadc1.Instance = ADC1;
  hadc1.Init.ClockPrescaler = ADC_CLOCK_SYNC_PCLK_DIV4;
  hadc1.Init.Resolution = ADC_RESOLUTION_12B;
  hadc1.Init.DataAlign = ADC_DATAALIGN_RIGHT;
  hadc1.Init.GainCompensation = 0;
  hadc1.Init.ScanConvMode = ADC_SCAN_ENABLE;
  hadc1.Init.EOCSelection = ADC_EOC_SINGLE_CONV;
  hadc1.Init.LowPowerAutoWait = DISABLE;
  hadc1.Init.ContinuousConvMode = ENABLE;
  hadc1.Init.NbrOfConversion = 3;
  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();
  }

  multimode.Mode = ADC_MODE_INDEPENDENT;
  if (HAL_ADCEx_MultiModeConfigChannel(&hadc1, &multimode) != HAL_OK)
  {
    Error_Handler();
  }

  sConfig.Channel = ADC_CHANNEL_1;
  sConfig.Rank = ADC_REGULAR_RANK_1;
  sConfig.SamplingTime = ADC_SAMPLETIME_92CYCLES_5;
  sConfig.SingleDiff = ADC_SINGLE_ENDED;
  sConfig.OffsetNumber = ADC_OFFSET_NONE;
  sConfig.Offset = 0;
  if (HAL_ADC_ConfigChannel(&hadc1, &sConfig) != HAL_OK)
  {
    Error_Handler();
  }

  sConfig.Channel = ADC_CHANNEL_2;
  sConfig.Rank = ADC_REGULAR_RANK_2;
  if (HAL_ADC_ConfigChannel(&hadc1, &sConfig) != HAL_OK)
  {
    Error_Handler();
  }

  sConfig.Channel = ADC_CHANNEL_9;
  sConfig.Rank = ADC_REGULAR_RANK_3;
  if (HAL_ADC_ConfigChannel(&hadc1, &sConfig) != HAL_OK)
  {
    Error_Handler();
  }
}

/**
  * @brief FDCAN1 Initialization Function
  *  None
  * @retval None
  */
static void MX_FDCAN1_Init(void)
{
  hfdcan1.Instance = FDCAN1;
  hfdcan1.Init.ClockDivider = FDCAN_CLOCK_DIV1;
  hfdcan1.Init.FrameFormat = FDCAN_FRAME_CLASSIC;
  hfdcan1.Init.Mode = FDCAN_MODE_NORMAL;
  hfdcan1.Init.AutoRetransmission = DISABLE;
  hfdcan1.Init.TransmitPause = DISABLE;
  hfdcan1.Init.ProtocolException = DISABLE;
  hfdcan1.Init.NominalPrescaler = 40;
  hfdcan1.Init.NominalSyncJumpWidth = 1;
  hfdcan1.Init.NominalTimeSeg1 = 14;
  hfdcan1.Init.NominalTimeSeg2 = 2;
  hfdcan1.Init.DataPrescaler = 1;
  hfdcan1.Init.DataSyncJumpWidth = 1;
  hfdcan1.Init.DataTimeSeg1 = 1;
  hfdcan1.Init.DataTimeSeg2 = 1;
  hfdcan1.Init.StdFiltersNbr = 0;
  hfdcan1.Init.ExtFiltersNbr = 0;
  hfdcan1.Init.TxFifoQueueMode = FDCAN_TX_FIFO_OPERATION;
  if (HAL_FDCAN_Init(&hfdcan1) != HAL_OK)
  {
    Error_Handler();
  }

  FDCAN_FilterTypeDef fdcan_filtre_yapi;

  fdcan_filtre_yapi.IdType = FDCAN_STANDARD_ID;
  fdcan_filtre_yapi.FilterIndex = 0;
  fdcan_filtre_yapi.FilterType = FDCAN_FILTER_MASK;
  fdcan_filtre_yapi.FilterConfig = FDCAN_FILTER_TO_RXFIFO0;
  fdcan_filtre_yapi.FilterID1 = 0x000;
  fdcan_filtre_yapi.FilterID2 = 0x000;

  HAL_FDCAN_ConfigFilter(&hfdcan1, &fdcan_filtre_yapi);
}

/**
  * @brief TIM16 Initialization Function
  *  None
  * @retval None
  */
static void MX_TIM16_Init(void)
{
  htim16.Instance = TIM16;
  htim16.Init.Prescaler = 1001;
  htim16.Init.CounterMode = TIM_COUNTERMODE_UP;
  htim16.Init.Period = 17001;
  htim16.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
  htim16.Init.RepetitionCounter = 0;
  htim16.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_DISABLE;
  if (HAL_TIM_Base_Init(&htim16) != HAL_OK)
  {
    Error_Handler();
  }
}

/**
  * Enable DMA controller clock
  */
static void MX_DMA_Init(void)
{
  __HAL_RCC_DMAMUX1_CLK_ENABLE();
  __HAL_RCC_DMA1_CLK_ENABLE();

  HAL_NVIC_SetPriority(DMA1_Channel1_IRQn, 0, 0);
  HAL_NVIC_EnableIRQ(DMA1_Channel1_IRQn);
}

/**
  * @brief GPIO Initialization Function
  *  None
  * @retval None
  */
static void MX_GPIO_Init(void)
{
  GPIO_InitTypeDef GPIO_InitStruct = {0};

  __HAL_RCC_GPIOC_CLK_ENABLE();
  __HAL_RCC_GPIOF_CLK_ENABLE();
  __HAL_RCC_GPIOA_CLK_ENABLE();

  HAL_GPIO_WritePin(GPIOA, GPIO_PIN_5, GPIO_PIN_RESET);

  GPIO_InitStruct.Pin = GPIO_PIN_13;
  GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  HAL_GPIO_Init(GPIOC, &GPIO_InitStruct);

  GPIO_InitStruct.Pin = GPIO_PIN_2|GPIO_PIN_3;
  GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
  GPIO_InitStruct.Alternate = GPIO_AF12_LPUART1;
  HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);

  GPIO_InitStruct.Pin = GPIO_PIN_5;
  GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
  HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
}

void Error_Handler(void)
{
  __disable_irq();
  while (1)
  {
  }
}

#ifdef  USE_FULL_ASSERT
void assert_failed(uint8_t *file, uint32_t line)
{
}
#endif /* USE_FULL_ASSERT */

[Andrew Neil]

---

@kyruss_21 wrote:

 I used two while loops, and as far as I understand, this is preventing me from seeing the data I'm getting from the sensor in the 'live expression' section.

---

Why do you think the loops would prevent that?

There seem to be many issues with the "Live Expression" feature - are you sure this is not just another?

Have you tried using something else? eg, output to a UART ?

[kyruss_21]

I was normally able to send and receive data via the PCan view. However, when using the while loop above, I couldn't read the sensor data. Upon reconsideration, I realized that having two while loops was a logical error.

[mƎALLEm]

Hello,

Which while loops? please specify the lines location in your code.

[Andrew Neil]

---

@kyruss_21 wrote:

Upon reconsideration, I realized that having two while loops was a logical error.

---

So the problem is with the code, not with the Data Visualiser?

[kyruss_21]

Line 89 and 327

[kyruss_21]

Yes, it worked fairly well when I tried to make the code simpler and just try to examine the sensor values.

[mƎALLEm · Accepted solution]

Here you are using while in an interrupt Callback  context:

void HAL_TIM_PeriodElapsedCallback(TIM_HandleTypeDef *htim)
{
    if (htim == &htim16)
    {
        while (HAL_FDCAN_GetRxFifoFillLevel(&hfdcan1, FDCAN_RX_FIFO0) > 0)
        {

So if you still receiving CAN frames in burst, the timer interrupt still blocked! you need to change that implementation either by replacing "while" by "if" condition or use a flag (variable) set in the timer callback interrupt and read the frames in your main when the flag is set and reset that flag after reading the CAN frames.