CAN communication not working F407 & G431

[bushy_foxx]

I have two Nucleo boards that are connected with a CAN bus (Transceiver SN65HVD230).

I would like to communicate with standard CAN, eight data bytes, data rate 50000 bit/s.

For the F407 all TX & RX events are triggering (reused old working code) the CubeMX settings (HCLK 168 MHz, periphiral clk 42 MHz) are:

The G431 is not working as expected, the CubeMX settings (HCLK 170 MHz, peripheral clocks 170 MHz) are:

The G431 TX/RX interrupts are working only in external Loopback mode in normal mode nothing triggers. Some code for the configuration of the G431 CAN:

HAL_StatusTypeDef CAN1_Start(int8_t CAN_HW_init)
{
	HAL_StatusTypeDef status;
	FDCAN_FilterTypeDef filterConfig;

	if(CAN_HW_init == 1)
	{
		MX_FDCAN1_Init();
	}

	// Configure Rx filter
	filterConfig.IdType = FDCAN_STANDARD_ID;
	filterConfig.FilterIndex = 0;
	filterConfig.FilterType = FDCAN_FILTER_MASK; // FDCAN_FILTER_RANGE;
	filterConfig.FilterConfig = FDCAN_FILTER_TO_RXFIFO0;
	filterConfig.FilterID1 = 0x000;
	filterConfig.FilterID2 = 0x000; // 0x7FF; // 0x1FFFFFFF; //

	if (HAL_FDCAN_ConfigFilter(&hfdcan1, &filterConfig) != HAL_OK)
	{
		Error_Handler();
	}

	// Start the FDCAN module
	status = HAL_FDCAN_Start(&hfdcan1);
	if (status != HAL_OK)
	{
		Error_Handler();
	}

	if (HAL_FDCAN_ActivateNotification(&hfdcan1, FDCAN_IT_TX_COMPLETE | FDCAN_IT_RX_FIFO0_NEW_MESSAGE, FDCAN_TX_BUFFER0 | FDCAN_RX_FIFO0) != HAL_OK)
	//if (HAL_FDCAN_ActivateNotification(&hfdcan1, FDCAN_IT_TX_COMPLETE | FDCAN_IT_RX_FIFO0_NEW_MESSAGE, FDCAN_TX_BUFFER0 | FDCAN_TX_BUFFER1 | FDCAN_TX_BUFFER2) != HAL_OK)
	//if (HAL_FDCAN_ActivateNotification(&hfdcan1, FDCAN_IT_TX_COMPLETE | FDCAN_IT_RX_FIFO0_NEW_MESSAGE, 0) != HAL_OK)
	{
		Error_Handler();
	}

	return status;
}

// send CAN message
void CAN1_TX(uint32_t CAN_ID, uint8_t CAN_RTR, uint8_t* CAN_Tx_Data)
{
	//FDCAN_TxHeaderTypeDef CanTxHeader;

	CanTxHeader.Identifier = CAN_ID;
	CanTxHeader.IdType = FDCAN_STANDARD_ID;
	CanTxHeader.DataLength = FDCAN_DLC_BYTES_8; // CAN_DLC; //
	CanTxHeader.ErrorStateIndicator = FDCAN_ESI_ACTIVE; // FDCAN_ESI_PASSIVE; //
	CanTxHeader.BitRateSwitch = FDCAN_BRS_OFF;
	CanTxHeader.FDFormat = FDCAN_CLASSIC_CAN; // FDCAN_FD_CAN;
	CanTxHeader.TxEventFifoControl = FDCAN_NO_TX_EVENTS; //FDCAN_STORE_TX_EVENTS; //
	CanTxHeader.MessageMarker = 0;

	if(CAN_RTR == 0)
	{
		CanTxHeader.TxFrameType = FDCAN_DATA_FRAME;
	}
	else
	{
		CanTxHeader.TxFrameType = FDCAN_REMOTE_FRAME;
	}


	/* Start the Transmission process */
	if (HAL_FDCAN_AddMessageToTxFifoQ(&hfdcan1, &CanTxHeader, CAN_Tx_Data) != HAL_OK)
	{
		/* Transmission request Error */
		Error_Handler();
	}
	HAL_Delay(10);
}

// Transmission Complete callback FDCAN_Tx_location
void HAL_FDCAN_TxBufferCompleteCallback(FDCAN_HandleTypeDef *hfdcan, uint32_t BufferIndexes)
{
	can_tx_ready = 1; // finished transmission
}

// FDCAN RX callback
void HAL_FDCAN_RxFifo0Callback(FDCAN_HandleTypeDef *hfdcan, uint32_t RxFifo0ITs)
{
	if((RxFifo0ITs & FDCAN_IT_RX_FIFO0_NEW_MESSAGE) != RESET)
	{
	    /* Retrieve Rx messages from RX FIFO0 */
	    if (HAL_FDCAN_GetRxMessage(hfdcan, FDCAN_RX_FIFO0, &CanRxHeader, can_rx_data) != HAL_OK)
	    {
	    	Error_Handler();
	    }

		can_state_change = 1;
	}
}

I need some advice, please help.

Best Regards,

Erik

[mƎALLEm]

Hello @bushy_foxx and welcome to the ST community,

You configured the FDCAN interface in Loopback mode for STM32G4. You need to change it to Normal mode and Classic format.

Also you need to use a crystal for CAN peripheral for both F4 and G4. Avoid using HSI and other internal RC sources.

[bushy_foxx]

The hardware that I am using is:

- STM32F407G-DISC1; there is a crystal HSE is selected

- STM32G431KBT6; there is no crystal on the board; the clock setting is as follows:

In switched between Loopback External and Normal Mode for the STM32G431KBT6

If I run the G4 in Loopback external, the TX & RX interrupts are triggered correctly (functions HAL_FDCAN_TxBufferCompleteCallback(...) and HAL_FDCAN_RxFifo0Callback(...), see code example initial post). Also the receive interrupt at the F407 is triggered; I can see the data while debugging the F407 with CubeIDE. Furthermore, I can see the bits on the oscilloscope.

If I run the G4 in Normal Mode no TX & RX Interrupt is triggered, the F407 is still connected to the bus for that hardware setup. Seems that nothing goes out on the TX line.

The SN65HVD230 Transceiver is on a CAN Waveshare Devboard, both sides 120 Ohm terminated, the cable in between is currently only about 1 m.

What are further useful checks?

Best Regards,
Erik