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kyruss_21
Associate II
February 23, 2026
Solved

Creating a CANopen Protocol

  • February 23, 2026
  • 1 reply
  • 338 views

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 */

 

 

Best answer by mƎALLEm

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.

1 reply

Andrew Neil
Andrew Neil
Super User
February 23, 2026
@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 ?

A complex system that works is invariably found to have evolved from a simple system that worked.A complex system designed from scratch never works and cannot be patched up to make it work.
K
kyruss_21Author
Associate II
February 23, 2026

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
mƎALLEm
Technical Moderator
February 23, 2026

Hello,

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

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