STM32 CAN Normal mode

DivyaJayan · ‎2024-09-10

Hi All,

I am currently working on the CAN normal mode in a custom board with MCU STM32F098RCT6 and CAN transceiver TJA1042. Very first I tried the loopback mode and it was successful. Then I am now trying to interface two custom boards using the normal mode. But there is no output.

Please give some insight about this.

Here is the code:

#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 ---------------------------------------------------------*/
CAN_HandleTypeDef hcan;

/* USER CODE BEGIN PV */

CAN_TxHeaderTypeDef  TxHeader;
CAN_RxHeaderTypeDef  RxHeader;

uint8_t TxData[2];
uint8_t RxData[2];

uint32_t TxMailbox;

/* USER CODE END PV */

/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_CAN_Init(void);
/* USER CODE BEGIN PFP */
HAL_StatusTypeDef  CAN_Polling(void);
/* 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_CAN_Init();
  /* USER CODE BEGIN 2 */

  if(CAN_Polling() != HAL_OK){
         while(1){}
       }

  /* USER CODE END 2 */

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

    /* USER CODE BEGIN 3 */
	  HAL_GPIO_TogglePin(GPIOC, GPIO_PIN_11);
	  HAL_Delay(500);
  }
  /* 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 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_NONE;
  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_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_HSI;
  RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
  RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV1;

  if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_0) != HAL_OK)
  {
    Error_Handler();
  }
}

/**
  * @brief CAN Initialization Function
  * @PAram None
  * @retval None
  */
static void MX_CAN_Init(void)
{

  /* USER CODE BEGIN CAN_Init 0 */

  /* USER CODE END CAN_Init 0 */

  /* USER CODE BEGIN CAN_Init 1 */

  /* USER CODE END CAN_Init 1 */
  hcan.Instance = CAN;
  hcan.Init.Prescaler = 16;
  hcan.Init.Mode = CAN_MODE_LOOPBACK;
  hcan.Init.SyncJumpWidth = CAN_SJW_1TQ;
  hcan.Init.TimeSeg1 = CAN_BS1_1TQ;
  hcan.Init.TimeSeg2 = CAN_BS2_1TQ;
  hcan.Init.TimeTriggeredMode = DISABLE;
  hcan.Init.AutoBusOff = DISABLE;
  hcan.Init.AutoWakeUp = DISABLE;
  hcan.Init.AutoRetransmission = ENABLE;
  hcan.Init.ReceiveFifoLocked = DISABLE;
  hcan.Init.TransmitFifoPriority = DISABLE;
  if (HAL_CAN_Init(&hcan) != HAL_OK)
  {
    Error_Handler();
  }
  /* USER CODE BEGIN CAN_Init 2 */

  /* USER CODE END CAN_Init 2 */

}

/**
  * @brief GPIO Initialization Function
  * @PAram 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_GPIOF_CLK_ENABLE();
  __HAL_RCC_GPIOA_CLK_ENABLE();
  __HAL_RCC_GPIOC_CLK_ENABLE();

  /*Configure GPIO pin Output Level */
  HAL_GPIO_WritePin(GPIOC, GPIO_PIN_11, GPIO_PIN_RESET);

  /*Configure GPIO pin : PC11 */
  GPIO_InitStruct.Pin = GPIO_PIN_11;
  GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
  HAL_GPIO_Init(GPIOC, &GPIO_InitStruct);

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

/* USER CODE BEGIN 4 */

HAL_StatusTypeDef  CAN_Polling(void){

	  CAN_FilterTypeDef   sFilterconfig;

	  sFilterconfig.FilterBank   = 0;
	  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 = CAN_FILTER_ENABLE;
	  sFilterconfig.SlaveStartFilterBank = 14;

	  if(HAL_CAN_ConfigFilter(&hcan, &sFilterconfig) != HAL_OK)
	  {
		  Error_Handler();
	  }

	  if(HAL_CAN_Start(&hcan) != HAL_OK)
	  {
		  Error_Handler();
	  }

	  TxHeader.IDE = CAN_ID_STD;
	  TxHeader.RTR = CAN_RTR_DATA;
	  TxHeader.StdId = 0x11;
	  TxHeader.DLC = 2;
	  TxHeader.TransmitGlobalTime = DISABLE;

	  TxData[0] = 0xCA;
	  TxData[1] = 0xFE;

	 if( HAL_CAN_AddTxMessage(&hcan, &TxHeader, TxData, &TxMailbox) != HAL_OK)
	 {
		 Error_Handler();
	 }

	 while(HAL_CAN_GetTxMailboxesFreeLevel(&hcan) != HAL_OK){}

	 if(HAL_CAN_GetRxFifoFillLevel(&hcan, CAN_RX_FIFO0) != HAL_OK)
	 {
		 Error_Handler();
	 }
	 if(HAL_CAN_GetRxMessage(&hcan, CAN_RX_FIFO0, &RxHeader, RxData) != HAL_OK)
	 {
		 Error_Handler();
	 }

	 return HAL_OK;
}

DivyaJayan · ‎2024-09-11

Here is the project file:

kumaichi · ‎2024-09-11

Not sure how useful this will be for you, but ControllersTech did an excellent video on CAN normal mode.

SofLit · ‎2024-09-11

In your code, you send and receive once in polling mode. So I don't know how you test that and what you expect as a behavior.

	 if( HAL_CAN_AddTxMessage(&hcan, &TxHeader, TxData, &TxMailbox) != HAL_OK)
	 {
		 Error_Handler();
	 }

	 while(HAL_CAN_GetTxMailboxesFreeLevel(&hcan) != HAL_OK){}

	 if(HAL_CAN_GetRxFifoFillLevel(&hcan, CAN_RX_FIFO0) != HAL_OK)
	 {
		 Error_Handler();
	 }
	 if(HAL_CAN_GetRxMessage(&hcan, CAN_RX_FIFO0, &RxHeader, RxData) != HAL_OK)
	 {
		 Error_Handler();
	 }

I modified your project (in attachement) to work in RX FIFO interrupt mode. SystemClock at 48MHz / CAN bitrate at 500kb/s (modified the prescaler, BS1 and BS2 with recommended values).

Unfortunately I don't have a board to test that MCU part number. So you need to test it from your side: in the Live Expression check RxData[].

Hope it helps.

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MHoll.2 · ‎2024-09-11

The circuit on CAN_STBY is putting the TJA1042BT probably in standby. The STB pin is a digital input, so setting it to 1.6V is definitively not a good idea. Please remove R5 to enable the Driver.

Martin

SofLit · ‎2024-09-11

@MHoll.2 wrote:

The circuit on CAN_STBY is putting the TJA1042BT probably in standby. The STB pin is a digital input, so setting it to 1.6V is definitively not a good idea. Please remove R5 to enable the Driver.

Martin

Yes it could be related to this.

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DivyaJayan · ‎2024-09-11

Hi,

I tried the interrupt code you have provided. But there is no change. Nothing is receiving as RxData.

And removed the R5 and checked again, again there is no change.

DivyaJayan · ‎2024-09-11

Hi,

thankyou for replying.

I am already using Controllers Tech video as a reference.

SofLit · ‎2024-09-11

Check your hardware. You need to check all the HW part of the CAN network. The power, the connections, the termination resistors.

You need to probe CAN_Tx and CAN_Rx pins and see what happens.

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