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CAN2 transmit the data but does not recieve in loopback mode

Ali Suleimani
Associate II

Hi

I am implementing CAN2 in STMCube IDE in loopback mode for microcontroller STM32F105. I have connected the tranciever to pins PB5 and PB6. this is the schematic:

AliSuleimani_0-1691396996419.png AliSuleimani_1-1691397030418.png

I can transmit the data but I do not receive it. I am not sure but think I have some problem in configuration. 

This is my code in STM32CubeIDE: AS you see I have highlighted the important part of the code. Help plz I don't know why I can not recive.

/* USER CODE BEGIN Header */
/**
  ******************************************************************************
  * @file           : main.c
  * @brief          : Main program body
  ******************************************************************************
  * @attention
  *
  * Copyright (c) 2023 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 hcan2;
 
/* USER CODE BEGIN PV */
 
/* USER CODE END PV */
 
/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_CAN2_Init(void);
/* USER CODE BEGIN PFP */
 
/* USER CODE END PFP */
 
/* Private user code ---------------------------------------------------------*/
/* USER CODE BEGIN 0 */
CAN_TxHeaderTypeDef TxHeader;
CAN_RxHeaderTypeDef RxHeader;
 
uint32_t TxMailbox;
uint32_t TxData[8];
uint32_t RxData[8];
uint32_t count=0;
 
void HAL_CAN_RxFifo0MsgPendingCallback(CAN_HandleTypeDef *hcan)
{
HAL_CAN_GetRxMessage(&hcan2,CAN_RX_FIFO0, &RxHeader, RxData);
}
 
 
 
 
/* 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_CAN2_Init();
  /* USER CODE BEGIN 2 */
  HAL_CAN_Start(&hcan2);
  HAL_CAN_ActivateNotification(&hcan2, CAN_IT_RX_FIFO0_MSG_PENDING);
  TxHeader.DLC = 1;
  TxHeader.ExtId = 0;
  TxHeader.IDE = CAN_ID_STD;
  TxHeader.RTR = CAN_RTR_DATA;
  TxHeader.StdId = 0x244;
  TxHeader.TransmitGlobalTime = DISABLE;
  TxData[0]= 0xf3;
  HAL_CAN_AddTxMessage(&hcan2, &TxHeader, TxData, &TxMailbox);
 
 
  /* USER CODE END 2 */
 
  /* Infinite loop */
  /* USER CODE BEGIN WHILE */
  while (1)
  {
    /* 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};
 
  /** 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.HSEPredivValue = RCC_HSE_PREDIV_DIV1;
  RCC_OscInitStruct.HSIState = RCC_HSI_ON;
  RCC_OscInitStruct.Prediv1Source = RCC_PREDIV1_SOURCE_HSE;
  RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
  RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
  RCC_OscInitStruct.PLL.PLLMUL = RCC_PLL_MUL9;
  RCC_OscInitStruct.PLL2.PLL2State = 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_CLOCKTYPE_PCLK2;
  RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
  RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
  RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV2;
  RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;
 
  if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_2) != HAL_OK)
  {
    Error_Handler();
  }
 
  /** Configure the Systick interrupt time
  */
  __HAL_RCC_PLLI2S_ENABLE();
}
 
/**
  * @brief CAN2 Initialization Function
  * @PAram 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 = 30;
  hcan2.Init.Mode = CAN_MODE_LOOPBACK;
  hcan2.Init.SyncJumpWidth = CAN_SJW_1TQ;
  hcan2.Init.TimeSeg1 = CAN_BS1_2TQ;
  hcan2.Init.TimeSeg2 = CAN_BS2_3TQ;
  hcan2.Init.TimeTriggeredMode = DISABLE;
  hcan2.Init.AutoBusOff = DISABLE;
  hcan2.Init.AutoWakeUp = ENABLE;
  hcan2.Init.AutoRetransmission = DISABLE;
  hcan2.Init.ReceiveFifoLocked = ENABLE;
  hcan2.Init.TransmitFifoPriority = ENABLE;
  if (HAL_CAN_Init(&hcan2) != HAL_OK)
  {
    Error_Handler();
  }
  /* USER CODE BEGIN CAN2_Init 2 */
 
  CAN_FilterTypeDef canfilterconfig;
 
  canfilterconfig.FilterActivation = CAN_FILTER_ENABLE;
  canfilterconfig.FilterBank = 0;  // anything between 0 to SlaveStartFilterBank
  canfilterconfig.FilterFIFOAssignment = CAN_RX_FIFO0;
  canfilterconfig.FilterIdHigh = 0x0000;
  canfilterconfig.FilterIdLow = 0x0000;
  canfilterconfig.FilterMaskIdHigh = 0x0000;
  canfilterconfig.FilterMaskIdLow = 0x0000;
  canfilterconfig.FilterMode = CAN_FILTERMODE_IDMASK;
  canfilterconfig.FilterScale = CAN_FILTERSCALE_32BIT;
  canfilterconfig.SlaveStartFilterBank = 14;  // 13 to 27 are assigned to slave CAN (CAN 2) OR 0 to 12 are assgned to CAN1
 
   if (HAL_CAN_ConfigFilter(&hcan2, &canfilterconfig)!=HAL_OK)
   {
   Error_Handler();
   }
  /* USER CODE END CAN2_Init 2 */
 
}
 
/**
  * @brief GPIO Initialization Function
  * @PAram None
  * @retval None
  */
static void MX_GPIO_Init(void)
{
 
  /* GPIO Ports Clock Enable */
  __HAL_RCC_GPIOD_CLK_ENABLE();
  __HAL_RCC_GPIOA_CLK_ENABLE();
  __HAL_RCC_GPIOB_CLK_ENABLE();
 
}
 
/* USER CODE BEGIN 4 */
 
/* 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.
  * @PAram  file: pointer to the source file name
  * @PAram  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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