CAN start API not executing in stm32F446RE board

[Komal]

Hi ST,

Can you please suggest me the solution of my problem, below is the problem statement

I have configured the stm32f446RE oard to use CAN1 in loopback mode, using CAN start in a function but the MSR bit 0 INAK is not resetting in the HAL_CAN_Start API

please find my code in the attachment 
i am use 500kbps baudrate.

Hoping for your quick response.

Note: Tried by increasing the CAN_TIMEOUT_VALUE but the CAN_Sart is not coming out of the while loop

/* Wait the acknowledge */
while ((hcan->Instance->MSR & CAN_MSR_INAK) != 0U)
{
/* Check for the Timeout */
if ((HAL_GetTick() - tickstart) > CAN_TIMEOUT_VALUE)

Requesting for fast response 

[SofLit]

Hello,

First, please use </> button to paste your code. Read our recommendations on this link: https://community.st.com/t5/community-guidelines/how-to-write-your-question-to-maximize-your-chances-to-find-a/ta-p/575228

Second, did you enable the internal pull-up resistor on CAN-RX pin?

Also see these parameters are bad:

  hcan1.Init.Prescaler = 6;
  hcan1.Init.TimeSeg1 = CAN_BS1_11TQ;
  hcan1.Init.TimeSeg2 = CAN_BS2_2TQ;

 See this thread: https://community.st.com/t5/stm32-mcus-products/can1-loopback-does-not-work-on-stm32f427/m-p/695622

[Komal]

please find the code 

/* 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 hcan1;

/* USER CODE BEGIN PV */
 CAN_TxHeaderTypeDef   TxHeader;
 CAN_RxHeaderTypeDef   RxHeader;
 uint8_t               TxData[8];
 uint8_t               RxData[8];
 uint32_t              TxMailbox;
 uint8_t			   test;
/* USER CODE END PV */

/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_CAN1_Init(void);
/* USER CODE BEGIN PFP */
static 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_CAN1_Init();
  /* USER CODE BEGIN 2 */

  /* USER CODE END 2 */

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

    /* USER CODE BEGIN 3 */
	  if(CAN_Polling() == HAL_OK)
	   {
	 	  test=1;
	   }
	   else
	   {
	 	  test=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_RCC_PWR_CLK_ENABLE();
  __HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE3);

  /** 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 = 16;
  RCC_OscInitStruct.PLL.PLLN = 336;
  RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV4;
  RCC_OscInitStruct.PLL.PLLQ = 2;
  RCC_OscInitStruct.PLL.PLLR = 2;
  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();
  }
}

/**
  * @brief CAN1 Initialization Function
  * @PAram 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 = 6;
  hcan1.Init.Mode = CAN_MODE_LOOPBACK;
  hcan1.Init.SyncJumpWidth = CAN_SJW_1TQ;
  hcan1.Init.TimeSeg1 = CAN_BS1_11TQ;
  hcan1.Init.TimeSeg2 = CAN_BS2_2TQ;
  hcan1.Init.TimeTriggeredMode = DISABLE;
  hcan1.Init.AutoBusOff = DISABLE;
  hcan1.Init.AutoWakeUp = DISABLE;
  hcan1.Init.AutoRetransmission = ENABLE;
  hcan1.Init.ReceiveFifoLocked = DISABLE;
  hcan1.Init.TransmitFifoPriority = DISABLE;
  if (HAL_CAN_Init(&hcan1) != HAL_OK)
  {
    Error_Handler();
  }

  /* USER CODE BEGIN CAN1_Init 2 */
  CAN_FilterTypeDef  sFilterConfig;

  /*##-2- Configure the CAN Filter ###########################################*/
  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 = 14;

  if(HAL_CAN_ConfigFilter(&hcan1, &sFilterConfig) != HAL_OK)
  {
    /* Filter configuration Error */
    Error_Handler();
  }


  /*##-3- Start the CAN peripheral ###########################################*/
  if (HAL_CAN_Start(&hcan1) != HAL_OK)
  {
    /* Start Error */
    Error_Handler();
  }

  /* USER CODE END CAN1_Init 2 */

}

/**
  * @brief GPIO Initialization Function
  * @PAram None
  * @retval None
  */
static void MX_GPIO_Init(void)
{

  /* GPIO Ports Clock Enable */
  __HAL_RCC_GPIOC_CLK_ENABLE();
  __HAL_RCC_GPIOH_CLK_ENABLE();
  __HAL_RCC_GPIOA_CLK_ENABLE();

}

/* USER CODE BEGIN 4 */
HAL_StatusTypeDef CAN_Polling(void)
{

  /*##-4- Start the Transmission process #####################################*/
  TxHeader.StdId = 0x11;
  TxHeader.RTR = CAN_RTR_DATA;
  TxHeader.IDE = CAN_ID_STD;
  TxHeader.DLC = 7;
  TxHeader.TransmitGlobalTime = DISABLE;
  TxData[0] = 0x43;
  TxData[1] = 0x52;
  TxData[2] = 0x45;
  TxData[3] = 0x56;
  TxData[4] = 0x41;
  TxData[5] = 0x56;
  TxData[6] = 0x49;

  /* Request transmission */
  if(HAL_CAN_AddTxMessage(&hcan1, &TxHeader, TxData, &TxMailbox) != HAL_OK)
  {
    /* Transmission request Error */
    Error_Handler();
  }

  /* Wait transmission complete */
  while(HAL_CAN_GetTxMailboxesFreeLevel(&hcan1) != 3) {}

  /*##-5- Start the Reception process ########################################*/
  if(HAL_CAN_GetRxFifoFillLevel(&hcan1, CAN_RX_FIFO0) != 1)
  {
    /* Reception Missing */
    Error_Handler();
  }

  if(HAL_CAN_GetRxMessage(&hcan1, CAN_RX_FIFO0, &RxHeader, RxData) != HAL_OK)
  {
    /* Reception Error */
    Error_Handler();
  }

 /* if((RxHeader.StdId != 0x11)                     ||
     (RxHeader.RTR != CAN_RTR_DATA)               ||
     (RxHeader.IDE != CAN_ID_STD)                 ||
     (RxHeader.DLC != 7)                          ||
     ((RxData[0]<<8 | RxData[1]) != 0xCAFE))
  {
     Rx message Error
    return HAL_ERROR;
  }*/

  return HAL_OK; /* Test Passed */
}

/* 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 */

[Komal]

The pins are no pull up no pull down

[SofLit · Accepted solution]

Hello,

I've already looked at your code from your attached main and you are using LoopBack mode.

So please review my answer in my previous comment:

1. - You need to set new values for BS1, BS2 and CAN prescaler: see this thread: https://community.st.com/t5/stm32-mcus-products/can1-loopback-does-not-work-on-stm32f427/m-p/695622
2. - You need to set the internal pull-up for CAN_Rx pin.

The code you shared don't give a full picture of all your configuration. You need to share your project including the ioc file.

EDIT: updated the correct link to the thread.