STM32f746 stops CAN transmission on higher CANBus load

[JStei.6]

Hello,

I am currently trying to figure out, how to send continuos information via CAN.

When threre are only a few nodes Connected to the network, everything is fine, bus as soon as the overall busload is bigger than ~70% then the STM32 MCU stops transmitting.

I have already set up some filters, so the fastest messages do net get received by the MCU but I am still having the same problem.

However, I can still receive all the messages that are designed to go through the filters.

I also found out, that ~1/4 of the STM32f746g_Disco boards we have, do not allow CAN transmission at all. Receiving is no problem.

Setup:

STM32f746g_Disco, used as an information display in an automobile.

CAN Baudrate: 500kbit/s

7 CAN Filters are used.

The transmitting request gets started by a timer driven interrupt.

Code:

//TxHeader Setup
  TxHeader1AE.DLC=8;
  TxHeader1AE.IDE = CAN_ID_STD;
  TxHeader1AE.StdId = 0x1AE;

//CAN Init
 hcan1.Instance = CAN1;
  hcan1.Init.Prescaler = 10;
  hcan1.Init.Mode = CAN_MODE_NORMAL;
  hcan1.Init.SyncJumpWidth = CAN_SJW_1TQ;
  hcan1.Init.TimeSeg1 = CAN_BS1_8TQ;
  hcan1.Init.TimeSeg2 = CAN_BS2_1TQ;
  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();
  }

//CAN Tx Routing, Timer driven
 
void TIM1_UP_TIM10_IRQHandler(void)
{
  /* USER CODE BEGIN TIM1_UP_TIM10_IRQn 0 */
 
  /* USER CODE END TIM1_UP_TIM10_IRQn 0 */
  HAL_TIM_IRQHandler(&htim10);
  /* USER CODE BEGIN TIM1_UP_TIM10_IRQn 1 */
  Data1AE[0] = xHeizungButton<<2;//(xHeizungButton<<2) + (xHeizungButton<<1);
  Data1AE[0] = Data1AE[0] + (xLufterButton<<1);
 
  HAL_CAN_AddTxMessage(&hcan1, &TxHeader1AE, Data1AE, &TxMailbox);
  iCanCounter++;
  /* USER CODE END TIM1_UP_TIM10_IRQn 1 */
}

//Variables
CAN_TxHeaderTypeDef   TxHeader1AE;
CAN_RxHeaderTypeDef   RxHeader;
uint8_t               TxData[8];
uint8_t               RxData[8];
uint32_t              TxMailbox;
 
uint8_t Data1AE[8]	={0};

Do you have any ideas on how to solve this problem?

Thanks in advance!