STM32F446ZET6 - Struggling to get the CAN running

[CBrun.5]

Hi,

I'm struggling to get the CAN working on a project I'm working on with the STM32F446ZET6. With the project below (CastletRestart) i just get a flat line of 3.3V high on the TX line for CAN1, this is being tested in loop back mode, with the TUT_CAN_F446 project the can works (downloaded from a tutorial) in loopback mode, as far as i can see ive replicated everything across but it still isnt working.

Its likely to be something silly and i do apologise for this being the case but i cannot see what ive missed having reviewed the code countless times.

P.s. i am aware the Tutorial project is targeted at a different micro, but the CAN1 ports are the same.

Any advice welcomed, thank you for your time

Chris

[mƎALLEm]

Hello,

You didn’t mention what problem you’ve faced? 

I assume the issue is the Rx side of TUT_CAN_F446.

By reviewing your code, 

This code is from “CastletRestart” side:

/* Private define ------------------------------------------------------------*/
/* USER CODE BEGIN PD */
#define DEBUG_LOOP 1u

	  CAN_TxHeaderTypeDef txHeader;
	  uint8_t data[2] = {0x55, 0xAA};
	  uint32_t mailbox;
/* USER CODE END PD */

/* Private macro -------------------------------------------------------------*/
/* USER CODE BEGIN PM */

/* USER CODE END PM */

/* Private variables ---------------------------------------------------------*/

/* USER CODE BEGIN PV */

/* USER CODE END PV */

/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(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();
  MX_ADC1_Init();
  /* USER CODE BEGIN 2 */
  HAL_ADC_Start_IT(&hadc1);
  HAL_CAN_Start(&hcan1);
  /* USER CODE END 2 */

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

    /* USER CODE BEGIN 3 */
#if DEBUG_LOOP
	  static bool toggle = false;
	  HAL_GPIO_WritePin(DIAG_LED2_GPIO_Port, DIAG_LED2_Pin, toggle);
	  HAL_GPIO_WritePin(DIAG_LED1_GPIO_Port, DIAG_LED1_Pin, toggle);
      toggle = !toggle;


                 HAL_CAN_AddTxMessage(&hcan1,&txHeader,&data[0], &mailbox);
      HAL_Delay(500);
#endif
  }
  /* USER CODE END 3 */
}

→ Here you didn’t initialize the txHeader structure therefore the ID sent by  “CastletRestart” is undefined.

In the same hand you are configuring a filter from the “TUT_CAN_F446” side:

  canfilterconfig.FilterFIFOAssignment = CAN_FILTER_FIFO0;
  canfilterconfig.FilterIdHigh = 0x103<<5;
  canfilterconfig.FilterIdLow = 0;
  canfilterconfig.FilterMaskIdHigh = 0x103<<5;
  canfilterconfig.FilterMaskIdLow = 0x0000;

→ most probably that undefined ID sent by “CastletRestart” doesn’t pass this filter. So instead set pass-all-IDs filter:

  canfilterconfig.FilterIdHigh = 0x0000;
  canfilterconfig.FilterIdLow = 0x0000;
  canfilterconfig.FilterMaskIdHigh = 0x0000;
  canfilterconfig.FilterMaskIdLow = 0x0000;

In other hand, please avoid HSI for the CAN communication in Normal mode. You have this from “CastletRestart” side:

Also avoid low BSx values for the CAN bit time setting such as BS1=BS2=2.

You can review these articles:

Hope that helps you as well as others ..