Not working for TxHeader.DataLength > FDCAN_DLC_BYTES_2

[JoseCSNeto]

Hi. I managed to make your example work on two NUCLEO-G431KB. Thank you for that.

Now, my problem is that I can't make it work with more than 2 bytes, even after setting TxHeader.DataLength = FDCAN_DLC_BYTES_3, etc..

Sketch:

#include <Arduino.h>
#include <SimpleCan.h>

static void handleCanMessage(FDCAN_RxHeaderTypeDef rxHeader, uint8_t *rxData);
static void init_CAN(void);
static void Button_Down(void);

// pass in optional shutdown and terminator pins that disable transceiver and add 120ohm resistor respectively
SimpleCan can1(-1, -1);
SimpleCan::RxHandler can1RxHandler(64, handleCanMessage);

FDCAN_TxHeaderTypeDef TxHeader;
uint8_t TxData[8];

void setup()
{
	Serial2.begin(9600);
	delay(3000);

	pinMode(LED_BUILTIN, OUTPUT);
	digitalWrite(LED_BUILTIN, HIGH);
	attachInterrupt(PB0, Button_Down, RISING);
	delay(100);
	init_CAN();
}

void loop()
{
}

static void init_CAN()
{
	Serial2.println(can1.init(CanSpeed::Mbit1) == HAL_OK
						? "CAN: initialized."
						: "CAN: error when initializing.");

	//DCAN_FilterTypeDef sFilterConfig;

	// Configure Rx filter
	// sFilterConfig.IdType = FDCAN_STANDARD_ID;
	// sFilterConfig.FilterIndex = 0;
	// sFilterConfig.FilterType = FDCAN_FILTER_MASK;
	// sFilterConfig.FilterConfig = FDCAN_FILTER_TO_RXFIFO0;
	// sFilterConfig.FilterID1 = 0x321;
	// sFilterConfig.FilterID2 = 0x7FF;

	// can1.configFilter(&sFilterConfig);
	// can1.configGlobalFilter(FDCAN_REJECT, FDCAN_REJECT, FDCAN_FILTER_REMOTE, FDCAN_FILTER_REMOTE);
	can1.activateNotification(&can1RxHandler);

	Serial2.println(can1.start() == HAL_OK
						? "CAN: started."
						: "CAN: error when starting.");
}

int dlcToLength(uint32_t dlc)
{
	int length = dlc >> 16;
	if (length >= 13)
	{
		return 32 + (13 - length) * 16;
	}
	else if (length == 12)
	{
		return 24;
	}
	else if (length >= 9)
	{
		return 12 + (9 - length) * 4;
	}
	return length;
}

static void handleCanMessage(FDCAN_RxHeaderTypeDef rxHeader, uint8_t *rxData)
{
	//Serial2.println("Recebi algo");

	int byte_length = dlcToLength(rxHeader.DataLength);

	Serial2.print("Received packet, id=0x");
	Serial2.print(rxHeader.Identifier, HEX);
	Serial2.print(", length=");
	Serial2.print(byte_length);
	for (int byte_index = 0; byte_index < byte_length; byte_index++)
	{
		Serial2.print(" byte[");
		Serial2.print(byte_index);
		Serial2.print("]=");
		Serial2.print(rxData[byte_index]);
		Serial2.print(" ");
	}
	Serial2.println();

	digitalToggle(LED_BUILTIN);
}

static void Button_Down()
{

	static uint8_t press_count = 0;

	press_count++;

	TxHeader.Identifier = 0x321;
	TxHeader.IdType = FDCAN_STANDARD_ID;
	TxHeader.TxFrameType = FDCAN_DATA_FRAME;
	TxHeader.DataLength = FDCAN_DLC_BYTES_3;
	TxHeader.ErrorStateIndicator = FDCAN_ESI_ACTIVE;
	TxHeader.BitRateSwitch = FDCAN_BRS_OFF;
	TxHeader.FDFormat = FDCAN_FD_CAN; // FDCAN_CLASSIC_CAN
	TxHeader.TxEventFifoControl = FDCAN_NO_TX_EVENTS;
	TxHeader.MessageMarker = 0;

	TxData[0] = press_count;
	TxData[1] = 0xAD;
	TxData[2] = 2;

	Serial2.print("CAN: sending message ");
	Serial2.println(can1.addMessageToTxFifoQ(&TxHeader, TxData) == HAL_OK ? "was ok." : "failed.");
}

Additional info:

• MCU: NUCLEO-G431KB
• Arduino_Core_STM32
• PlatformIO IDE version 2.3.0
  Thank you.

[owennewo]

What error are you seeing? Is it printing 'CAN: sending message failed"?
It might be worth checking what can1.addMessageToTxFifoQ is returning it might be HAL_BUSY or HAL_ERROR

I've looked at the code. I can see a bit of a weird bit on the receiving end but the sending bit looks ok.

The bit that looks weird is:

public:
		RxHandler(uint16_t dataLength, void(*callback)(FDCAN_RxHeaderTypeDef rxHeader, uint8_t *rxData));
		~RxHandler();

		void notify(FDCAN_HandleTypeDef *hfdcan);
	private:
		FDCAN_RxHeaderTypeDef _rxHeader;
		uint8_t *_rxData;
		void(*_callback)(FDCAN_RxHeaderTypeDef, uint8_t *);
	};

I can't see where rxData is initialized.

The code was originally written by erwin74 and discussed here:
https://community.simplefoc.com/t/can-bus-support/407
The stm part of the code was initially writtern by erwin73

[JoseCSNeto]

It's seems to be actually sending the message: addMessageToTxFifoQ returns HAL_OK -> "CAN: sending message was ok.".

I guess the problem is on the receiving side.

_rxData is initialized here (SimpleCan.cpp), but I'm not so sure about rxData.

SimpleCan::RxHandler::RxHandler(uint16_t dataLength, void (*callback)(FDCAN_RxHeaderTypeDef, uint8_t *))
{
	_rxData = new byte[dataLength];
	_callback = callback;
}

Tomorrow I'll compare this with another example and see if I can come up with the solution.

[owennewo]

Can you remove most of the code from handleCanMessage and see if the function is triggered e.g.

static void handleCanMessage(FDCAN_RxHeaderTypeDef rxHeader, uint8_t *rxData)
{
	Serial.println("received");

	digitalToggle(LED_BUILTIN);
}

[JoseCSNeto]

Will try that tomorrow, thanks.

EDIT: It is receiving. Must be blocking somewhere on the handleCanMessage function.

EDIT2: It works if I print it out of the for loop. Serial.print is blocking for some reason?
Example for TxHeader.DataLength = FDCAN_DLC_BYTES_3:

Serial2.println(rxData[0]);
Serial2.print(" ");
Serial2.println(rxData[1]);
Serial2.print(" ");
Serial2.println(rxData[2]);
Serial2.println();

EDIT3: This bit of code inside the for loop blocks everything for some reason:

Serial2.print(" byte[");
Serial2.print(byte_index);
Serial2.print("]=");

When I commented it out it stopped blocking.