STM32F407VET CAN BUS interrupt does not trigger

[JBond.1]

Hi, I am trying to communicate on CAN BUS, I have previously succeeded in doing so with STM32F103C8 and STM32F091RC, but I cant make it work on STM32F407VET It does not trigger its interrupt on message receive. What could be the difference on this MCU? Do I need to enable something different?

MCU clock 168Mhz, APB1 42Mhz, CAN BUS speed is 100000bit/s, enabled "CAN1 RX0 interrupts" in NVIC, code:

hcan1.Instance = CAN1;
hcan1.Init.Prescaler = 28;
hcan1.Init.Mode = CAN_MODE_NORMAL;
hcan1.Init.SyncJumpWidth = CAN_SJW_1TQ;
hcan1.Init.TimeSeg1 = CAN_BS1_12TQ;
hcan1.Init.TimeSeg2 = CAN_BS2_2TQ;
hcan1.Init.TimeTriggeredMode = DISABLE;
hcan1.Init.AutoBusOff = ENABLE;
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_FilterTypeDef  sFilterConfig;
sFilterConfig.FilterBank = 0;
sFilterConfig.FilterMode = CAN_FILTERMODE_IDMASK;
sFilterConfig.FilterScale = CAN_FILTERSCALE_32BIT;
sFilterConfig.FilterIdHigh = 0x0000;
sFilterConfig.FilterIdLow = 0x0000;
sFilterConfig.FilterMaskIdHigh = 0x0000;
sFilterConfig.FilterMaskIdLow = 0x0000;
sFilterConfig.FilterFIFOAssignment = CAN_RX_FIFO0;
sFilterConfig.FilterActivation = ENABLE;
sFilterConfig.SlaveStartFilterBank = 14;
 
if (HAL_CAN_ConfigFilter(hcan1, &sFilterConfig) != HAL_OK)
{
	Error_Handler();
}
 
if (HAL_CAN_Start(hcan1) != HAL_OK)
{
	Error_Handler();
}
 
if (HAL_CAN_ActivateNotification(hcan1, CAN_IT_RX_FIFO0_MSG_PENDING) != HAL_OK)
{
	Error_Handler();
}

I am expecting to get callback on:

void HAL_CAN_RxFifo0MsgPendingCallback(CAN_HandleTypeDef *hcan)
{
}

But its never executed. I tried to set break point on, but it does not brake there ether:

/**
  * @brief This function handles CAN1 RX0 interrupts.
  */
void CAN1_RX0_IRQHandler(void)
{
  /* USER CODE BEGIN CAN1_RX0_IRQn 0 */
 
  /* USER CODE END CAN1_RX0_IRQn 0 */
  HAL_CAN_IRQHandler(&hcan1);
  /* USER CODE BEGIN CAN1_RX0_IRQn 1 */
 
  /* USER CODE END CAN1_RX0_IRQn 1 */
}

 What could be the problem?

I dont know what to trouble shoot next.

[JBond.1]

Both MCU has external transceivers, I switched places to make sure that both transceivers work. STM32F091 works on both of them, STM32F407 does not.

[SKacp.1 · Accepted solution]

Hi,

Probably You have problem with settings of SystemClock.

You have on the board STM32F4VE 8 MHz external resonator?

If yes, please change value from RCC_OscInitStruct.PLL.PLLM = 25 to RCC_OscInitStruct.PLL.PLLM = 8,

Best Regards,

Slawek

[JBond.1]

Thanks for your reply! Indeed its issue with SystemClock, I have 8Mhz external resonator, not sure why its by default 25Mhz. I have changed settings:

Now I am able to send CAN BUS messages from STM32F4 and other can read them!

But STM32F4 is still not receiving messages, interrupt is not triggering...

[SKacp.1]

Hi,

Please add in Your function:

void HAL_CAN_RxFifo0MsgPendingCallback(CAN_HandleTypeDef *hcan)
{
	led = !led;
	GPIO_SetLed(!led);
	GPIO_SetLed2(led);
}

function HAL_CAN_GetRxMessage

I think so You should get the data from the bufor FIFO RX.

Best Regards,

Slawek

[JBond.1]

Thank you! I found another root cause. It seems that ST-Link and MCU must share same power supply or ground and then I receive CAN BUS interrupts!

Yes I should also use HAL_CAN_GetRxMessage as you said.

So there were 2 root causes SystemClock and common ground or power supply with debugger. Do you know why does it need common ground?

Again thanks for your help, I was loosing hope!