CAN Transmit mailbox callback function understanding

Ash1 · ‎2025-01-15

Hi

My board is STM32F407G so I want to understand the tx mailbox callback once interrupt hit I am sharing project in which I am sending CAN1 to CAN2 and CAN2 to CAN1 in loop back mode same ID.

So rxindication is working fine and this is the project I got from one of your technical executive ,so how will "hcan->TxMailbox0CompleteCallback(hcan);" get called because in above line we are clearing "

/* Clear the Transmission Complete flag (and TXOK0,ALST0,TERR0 bits) */

__HAL_CAN_CLEAR_FLAG(hcan, CAN_FLAG_RQCP0);"

which also clears "if ((tsrflags & CAN_TSR_TXOK0) != 0U)" TXOK0 bit also so if condition will not satisfy . please guide me

/* Transmit Mailbox empty interrupt management *****************************/

if ((interrupts & CAN_IT_TX_MAILBOX_EMPTY) != 0U)

{

/* Transmit Mailbox 0 management *****************************************/

if ((tsrflags & CAN_TSR_RQCP0) != 0U)

{

/* Clear the Transmission Complete flag (and TXOK0,ALST0,TERR0 bits) */

__HAL_CAN_CLEAR_FLAG(hcan, CAN_FLAG_RQCP0);



if ((tsrflags & CAN_TSR_TXOK0) != 0U)

{

/* Transmission Mailbox 0 complete callback */

#if USE_HAL_CAN_REGISTER_CALLBACKS == 1

/* Call registered callback*/

hcan->TxMailbox0CompleteCallback(hcan);

#else

/* Call weak (surcharged) callback */

HAL_CAN_TxMailbox0CompleteCallback(hcan);

#endif /* USE_HAL_CAN_REGISTER_CALLBACKS */

}

/* 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"

/* 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 hcan1;
CAN_HandleTypeDef hcan2;

/* USER CODE BEGIN PV */
CAN_FilterTypeDef  sFilterConfig;
__IO uint32_t i = 0;
// CAN1
CAN_TxHeaderTypeDef   CAN1_TxHeader;
CAN_RxHeaderTypeDef   CAN1_RxHeader[9];
uint8_t               CAN1_TxData[2] = {0};
uint8_t               CAN1_RxData[2] = {0};
uint32_t              CAN1_TxMailbox;
uint32_t              CAN1_Tx_ID_List[3] = {0x501,0x502,0x503};
__IO uint8_t          CAN1_Rx_cnt = 0;
// CAN2
CAN_TxHeaderTypeDef   CAN2_TxHeader;
CAN_RxHeaderTypeDef   CAN2_RxHeader[9];
uint8_t               CAN2_TxData[2] = {0};
uint8_t               CAN2_RxData[2] = {0};
uint32_t              CAN2_TxMailbox;
uint32_t              CAN2_Tx_ID_List[3] = {0x501,0x502,0x503};
__IO uint8_t          CAN2_Rx_cnt = 0;
/* 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);
/* USER CODE BEGIN PFP */

/* 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();
  /* USER CODE BEGIN 2 */
  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_RX_FIFO0;
  sFilterConfig.FilterActivation = ENABLE;
  sFilterConfig.SlaveStartFilterBank = 1;
  
  if(HAL_CAN_ConfigFilter(&hcan1, &sFilterConfig) != HAL_OK)
  {
    /* Filter configuration Error */
    Error_Handler();
  }
  
  sFilterConfig.FilterBank = 1;
  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_RX_FIFO0;
  sFilterConfig.FilterActivation = ENABLE;
  sFilterConfig.SlaveStartFilterBank = 1;
  
  if(HAL_CAN_ConfigFilter(&hcan2, &sFilterConfig) != HAL_OK)
  {
    /* Filter configuration Error */
    Error_Handler();
  }  
  
  if (HAL_CAN_ActivateNotification(&hcan1, CAN_IT_RX_FIFO0_MSG_PENDING) != HAL_OK)
  {
    /* Notification Error */
    Error_Handler();
  }  
  
  if (HAL_CAN_ActivateNotification(&hcan2, CAN_IT_RX_FIFO0_MSG_PENDING) != HAL_OK)
  {
    /* Notification Error */
    Error_Handler();
  }   
  
  CAN1_TxHeader.ExtId = CAN2_TxHeader.ExtId = 0x01;
  CAN1_TxHeader.RTR = CAN2_TxHeader.RTR = CAN_RTR_DATA;
  CAN1_TxHeader.IDE = CAN2_TxHeader.IDE = CAN_ID_STD;
  CAN1_TxHeader.DLC = CAN2_TxHeader.DLC = 2;
  CAN1_TxHeader.TransmitGlobalTime = CAN2_TxHeader.TransmitGlobalTime = DISABLE;
  
  /* USER CODE END 2 */

  /* Infinite loop */
  /* USER CODE BEGIN WHILE */
  while (1)
  {
      CAN1_TxHeader.StdId = CAN1_Tx_ID_List[i];
      CAN1_TxData[0] ++;
      CAN1_TxData[1] --;
        if (HAL_CAN_AddTxMessage(&hcan1, &CAN1_TxHeader, CAN1_TxData, &CAN1_TxMailbox) != HAL_OK)
        {
          /* Transmission request Error */
          Error_Handler();
        }
        HAL_Delay(10);      
        
      CAN2_TxHeader.StdId = CAN2_Tx_ID_List[i];
        if (HAL_CAN_AddTxMessage(&hcan2, &CAN2_TxHeader, CAN2_TxData, &CAN2_TxMailbox) != HAL_OK)
        {
          /* Transmission request Error */
          Error_Handler();
        }
        HAL_Delay(10);  
        i++;
        if (i == 3) i = 0; 

    /* USER CODE END WHILE */

    /* USER CODE BEGIN 3 */
  }
  /* 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_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 = 8;
  RCC_OscInitStruct.PLL.PLLN = 168;
  RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV2;
  RCC_OscInitStruct.PLL.PLLQ = 4;
  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_DIV4;
  RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV2;

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

/**
  * @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 = 4;
  hcan1.Init.Mode = CAN_MODE_LOOPBACK;
  hcan1.Init.SyncJumpWidth = CAN_SJW_1TQ;
  hcan1.Init.TimeSeg1 = CAN_BS1_15TQ;
  hcan1.Init.TimeSeg2 = CAN_BS2_5TQ;
  hcan1.Init.TimeTriggeredMode = DISABLE;
  hcan1.Init.AutoBusOff = DISABLE;
  hcan1.Init.AutoWakeUp = DISABLE;
  hcan1.Init.AutoRetransmission = DISABLE;
  hcan1.Init.ReceiveFifoLocked = DISABLE;
  hcan1.Init.TransmitFifoPriority = DISABLE;
  if (HAL_CAN_Init(&hcan1) != HAL_OK)
  {
    Error_Handler();
  }
  /* USER CODE BEGIN CAN1_Init 2 */
  if (HAL_CAN_Start(&hcan1) != HAL_OK)
  {
    /* Start Error */
    Error_Handler();
  }
  /* USER CODE END CAN1_Init 2 */

}

/**
  * @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 = 4;
  hcan2.Init.Mode = CAN_MODE_LOOPBACK;
  hcan2.Init.SyncJumpWidth = CAN_SJW_1TQ;
  hcan2.Init.TimeSeg1 = CAN_BS1_15TQ;
  hcan2.Init.TimeSeg2 = CAN_BS2_5TQ;
  hcan2.Init.TimeTriggeredMode = DISABLE;
  hcan2.Init.AutoBusOff = DISABLE;
  hcan2.Init.AutoWakeUp = DISABLE;
  hcan2.Init.AutoRetransmission = DISABLE;
  hcan2.Init.ReceiveFifoLocked = DISABLE;
  hcan2.Init.TransmitFifoPriority = DISABLE;
  if (HAL_CAN_Init(&hcan2) != HAL_OK)
  {
    Error_Handler();
  }
  /* USER CODE BEGIN CAN2_Init 2 */
  if (HAL_CAN_Start(&hcan2) != HAL_OK)
  {
    /* Start Error */
    Error_Handler();
  }
  /* USER CODE END CAN2_Init 2 */

}

/**
  * @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_GPIOH_CLK_ENABLE();
  __HAL_RCC_GPIOB_CLK_ENABLE();
  __HAL_RCC_GPIOA_CLK_ENABLE();

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

/* USER CODE BEGIN 4 */
void HAL_CAN_RxFifo0MsgPendingCallback(CAN_HandleTypeDef *hcan)
{
  /* Get RX message */
  if(hcan->Instance == CAN1)
  {
    if (HAL_CAN_GetRxMessage(hcan, CAN_RX_FIFO0, &CAN1_RxHeader[CAN1_Rx_cnt++], CAN1_RxData) != HAL_OK)
      {
         /* Reception Error */
         Error_Handler();
      }
  
   if(CAN1_Rx_cnt == 9) CAN1_Rx_cnt = 0;
  }
  else if(hcan->Instance == CAN2) 
  {
     if (HAL_CAN_GetRxMessage(hcan, CAN_RX_FIFO0, &CAN2_RxHeader[CAN2_Rx_cnt++], CAN2_RxData) != HAL_OK)
      {
         /* Reception Error */
         Error_Handler();
      }
     if(CAN2_Rx_cnt == 9) CAN2_Rx_cnt = 0;
  }    

}
/* 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 */

Ash1 · ‎2025-01-19

Hi all

Still I haven't received any response related this.

SofLit · ‎2025-01-20

Hello,

Not sure I understood the issue.

In your attached example you didn't activate the Tx empty interrupt with no Tx callback declared. How do you expect to get Tx callback called?

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