STM32H7 FDCAN FIFO FULL (lack of ACK)

[Mden .1]

Hello,

I am currently working on a motor setup between an STM32H750VBT6 with a CJMCU-1051 and a motordriver VESC mini FESC 4.20. I have 5 PDO messages coming from de Motor controller which I can read in normal mode. However, after a while the STM32H7xx seems to stop with sending can messages. The error code, which it returns, is 512 (HAL_FDCAN_ERROR_FIFO_FULL). 

I tried to set the mode to external_loopback, which eliminated the problem. However, I cannot receive any messages coming from the canbus, because this mode blocks incoming data. The problem is that the Motor controller won’t acknowledge my messages.

Is there a way to automatically acknowledge the transmitted messages, while receiving can messages as well. or configure FDCAN without ack requirements? Thanks a lot.

init code:

void STM32_CANFD_DRIVER::can_init(uint16_t id)

{

   UNUSED(id);

   _hfdcan.Init.FrameFormat = FDCAN_FRAME_CLASSIC;

   _hfdcan.Init.Mode = FDCAN_MODE_NORMAL;

   _hfdcan.Init.TransmitPause = DISABLE;

   _hfdcan.Init.ProtocolException = DISABLE;

   _hfdcan.Init.NominalPrescaler = prescaler;

   _hfdcan.Init.NominalSyncJumpWidth = 15;

   _hfdcan.Init.NominalTimeSeg1 = bs1;

   _hfdcan.Init.NominalTimeSeg2 = bs2;

   _hfdcan.Init.DataPrescaler = prescaler;

   _hfdcan.Init.DataSyncJumpWidth = 15;

   _hfdcan.Init.DataTimeSeg1 = bs1;

   _hfdcan.Init.DataTimeSeg2 = bs2;

   _hfdcan.Init.AutoRetransmission = DISABLE;

   _hfdcan.Init.MessageRAMOffset = _hfdcan.Instance == FDCAN1 ? 0 : 1024;

   _hfdcan.Init.StdFiltersNbr = 8;

   _hfdcan.Init.ExtFiltersNbr = 0;

   _hfdcan.Init.RxFifo0ElmtsNbr = 8;

   _hfdcan.Init.RxFifo0ElmtSize = FDCAN_DATA_BYTES_8;

   _hfdcan.Init.RxFifo1ElmtsNbr = 0;

   _hfdcan.Init.RxFifo1ElmtSize = FDCAN_DATA_BYTES_8;

   _hfdcan.Init.RxBuffersNbr = 8;

   _hfdcan.Init.RxBufferSize = FDCAN_DATA_BYTES_8;

   _hfdcan.Init.TxEventsNbr = 8;

   _hfdcan.Init.TxBuffersNbr = 8;

   _hfdcan.Init.TxFifoQueueElmtsNbr = 8;

   _hfdcan.Init.TxFifoQueueMode = FDCAN_TX_FIFO_OPERATION;

   _hfdcan.Init.TxElmtSize = FDCAN_DATA_BYTES_8;

   if (HAL_FDCAN_Init(&_hfdcan) != HAL_OK)

   {

       Error_Handler();

   }

   bus_state = BUS_OFF;

}

void STM32_CANFD_DRIVER::can_enable(void)

{

   if (bus_state == BUS_OFF) {

       if (HAL_FDCAN_Start(&_hfdcan) != HAL_OK)

       {

           Error_Handler();

       }

       bus_state = BUS_OK;

   }

}

Transmit code:

CanState STM32_CANFD_DRIVER::can_tx(CAN_FRAME* tx_frame, uint32_t timeout)

{

FDCAN_TxHeaderTypeDef tx_header;

   tx_header.BitRateSwitch = FDCAN_BRS_OFF;

switch (tx_frame->length) {

   case 0:

       tx_header.DataLength = FDCAN_DLC_BYTES_0;

       break;

   case 1:

       tx_header.DataLength = FDCAN_DLC_BYTES_1;

       break;

   case 2:

       tx_header.DataLength = FDCAN_DLC_BYTES_2;

       break;

   case 3:

       tx_header.DataLength = FDCAN_DLC_BYTES_3;

       break;

   case 4:

       tx_header.DataLength = FDCAN_DLC_BYTES_4;

       break;

   case 5:

       tx_header.DataLength = FDCAN_DLC_BYTES_5;

       break;

   case 6:

       tx_header.DataLength = FDCAN_DLC_BYTES_6;

       break;

   case 7:

       tx_header.DataLength = FDCAN_DLC_BYTES_7;

       break;

   case 8:

       tx_header.DataLength = FDCAN_DLC_BYTES_8;

       break;

   default:

       Error_Handler();

       break;

   }

   tx_header.FDFormat = FDCAN_CLASSIC_CAN;

   tx_header.Identifier = tx_frame->id;

   if (tx_frame->extended) {

       tx_header.IdType = FDCAN_EXTENDED_ID;

   }

   else {

       tx_header.IdType = FDCAN_STANDARD_ID;

   }

   tx_header.TxFrameType = tx_frame->rtr ? FDCAN_REMOTE_FRAME : FDCAN_DATA_FRAME;

   tx_header.ErrorStateIndicator = FDCAN_ESI_ACTIVE;

   tx_header.MessageMarker = 0;

   tx_header.TxEventFifoControl = FDCAN_NO_TX_EVENTS; // Should we do this or the other

   if (HAL_FDCAN_AddMessageToTxFifoQ(&_hfdcan, &tx_header, tx_frame->data.uint8) != HAL_OK) {

       LOGGER_PRINTF("CANFD FAILED TO TRANSMIT MESSAGE STM32_CANFD_driver:%d\n", __LINE__);

   }

   return DATA_OK;

}