STM32F using HAL_CAN Library

Question

I'm trying to communicate over CAN using the HAL_CAN library between two STM32F boards. Specifically the issue seems to be in receiving messages. Following the documentation:

 ==============================================================================
                    ##### How to use this driver #####
[..]
  (#) Initialize the CAN low level resources by implementing the
      HAL_CAN_MspInit():
     (++) Enable the CAN interface clock using __HAL_RCC_CANx_CLK_ENABLE()
     (++) Configure CAN pins
         (+++) Enable the clock for the CAN GPIOs
         (+++) Configure CAN pins as alternate function open-drain
     (++) In case of using interrupts (e.g. HAL_CAN_ActivateNotification())
         (+++) Configure the CAN interrupt priority using
               HAL_NVIC_SetPriority()
         (+++) Enable the CAN IRQ handler using HAL_NVIC_EnableIRQ()
         (+++) In CAN IRQ handler, call HAL_CAN_IRQHandler()

  (#) Initialize the CAN peripheral using HAL_CAN_Init() function. This
      function resorts to HAL_CAN_MspInit() for low-level initialization.

  (#) Configure the reception filters using the following configuration
      functions:
        (++) HAL_CAN_ConfigFilter()

  (#) Start the CAN module using HAL_CAN_Start() function. At this level
      the node is active on the bus: it receive messages, and can send
      messages.

  (#) To manage messages transmission, the following Tx control functions
      can be used:
        (++) HAL_CAN_AddTxMessage() to request transmission of a new
             message.
        (++) HAL_CAN_AbortTxRequest() to abort transmission of a pending
             message.
        (++) HAL_CAN_GetTxMailboxesFreeLevel() to get the number of free Tx
             mailboxes.
        (++) HAL_CAN_IsTxMessagePending() to check if a message is pending
             in a Tx mailbox.
        (++) HAL_CAN_GetTxTimestamp() to get the timestamp of Tx message
             sent, if time triggered communication mode is enabled.

  (#) When a message is received into the CAN Rx FIFOs, it can be retrieved
      using the HAL_CAN_GetRxMessage() function. The function
      HAL_CAN_GetRxFifoFillLevel() allows to know how many Rx message are
      stored in the Rx Fifo.

  (#) Calling the HAL_CAN_Stop() function stops the CAN module.

  (#) The deinitialization is achieved with HAL_CAN_DeInit() function.


  *** Polling mode operation ***
  ==============================
[..]
  (#) Reception:
        (++) Monitor reception of message using HAL_CAN_GetRxFifoFillLevel()
             until at least one message is received.
        (++) Then get the message using HAL_CAN_GetRxMessage().

  (#) Transmission:
        (++) Monitor the Tx mailboxes availability until at least one Tx
             mailbox is free, using HAL_CAN_GetTxMailboxesFreeLevel().
        (++) Then request transmission of a message using
             HAL_CAN_AddTxMessage().


  *** Interrupt mode operation ***
  ================================
[..]
  (#) Notifications are activated using HAL_CAN_ActivateNotification()
      function. Then, the process can be controlled through the
      available user callbacks: HAL_CAN_xxxCallback(), using same APIs
      HAL_CAN_GetRxMessage() and HAL_CAN_AddTxMessage().

  (#) Notifications can be deactivated using
      HAL_CAN_DeactivateNotification() function.

  (#) Special care should be taken for CAN_IT_RX_FIFO0_MSG_PENDING and
      CAN_IT_RX_FIFO1_MSG_PENDING notifications. These notifications trig
      the callbacks HAL_CAN_RxFIFO0MsgPendingCallback() and
      HAL_CAN_RxFIFO1MsgPendingCallback(). User has two possible options
      here.
        (++) Directly get the Rx message in the callback, using
             HAL_CAN_GetRxMessage().
        (++) Or deactivate the notification in the callback without
             getting the Rx message. The Rx message can then be got later
             using HAL_CAN_GetRxMessage(). Once the Rx message have been
             read, the notification can be activated again.

1. I'm calling HAL_CAN_Init , which in turns calls HAL_CAN_MspInit setting the clock, enabling the GPIOs and configuring the CAN pins as alternate function open drain. As I'm using interrupts it also sets the receive interrupt as:

    HAL_NVIC_SetPriority(CAN1_RX0_IRQn, 0, 0);
    HAL_NVIC_EnableIRQ(CAN1_RX0_IRQn);

2. Reception filters are being set as follows using HAL_CAN_ConfigFilter() , and no error is returned:

  sFilterConfig.FilterFIFOAssignment = CAN_FILTER_FIFO0;
  sFilterConfig.FilterIdHigh = 0;
  sFilterConfig.FilterIdLow = 0;
  sFilterConfig.FilterMaskIdHigh = 0;
  sFilterConfig.FilterMaskIdLow = 0;
  sFilterConfig.FilterScale = CAN_FILTERSCALE_32BIT;
  sFilterConfig.FilterActivation = ENABLE;
  sFilterConfig.FilterBank = 0;
  sFilterConfig.FilterMode = CAN_FILTERMODE_IDMASK;
  sFilterConfig.SlaveStartFilterBank = 14;
  HAL_CAN_ConfigFilter(&hcan1, &sFilterConfig)

3. HAL_CAN_Start is called and no error is returned:

HAL_CAN_Start(&hcan1)

4. Using an interrupt triggered by pressing the blue pushbutton a message is sent:

void EXTI0_IRQHandler(void)
{
  /* USER CODE BEGIN EXTI0_IRQn 0 */
for(int n=0;n<1000000;n++);
if (HAL_GPIO_ReadPin(GPIOA, GPIO_PIN_0) == GPIO_PIN_SET) {
    a++;
    if(HAL_CAN_GetTxMailboxesFreeLevel(&hcan1)){
        if(HAL_CAN_AddTxMessage(&hcan1, &pHeader, &a, &TxMailbox)==HAL_OK){
                if(HAL_GPIO_ReadPin(GPIOG, GPIO_PIN_6) == GPIO_PIN_SET){
                    HAL_GPIO_WritePin(GPIOG, GPIO_PIN_6, GPIO_PIN_RESET);
                } else{
                    HAL_GPIO_WritePin(GPIOG, GPIO_PIN_6, GPIO_PIN_SET);
                }
        }
    }
}

5. I've verified the message is pending as the following returns a positive value:

HAL_CAN_IsTxMessagePending(&hcan1, TxMailbox)

6. However the following interrupt that should be triggered when a messaged is available to be received is never triggered:

void CAN1_RX0_IRQHandler(void)
{
  HAL_CAN_IRQHandler(&hcan1);
  /* USER CODE BEGIN CAN1_RX0_IRQn 1 */
  HAL_CAN_GetRxMessage(&hcan1, CAN_RX_FIFO0, &pRxHeader, &r);
  HAL_GPIO_WritePin(GPIOK, GPIO_PIN_3, GPIO_PIN_RESET);

  /* USER CODE END CAN1_RX0_IRQn 1 */
}

Other notes:

• Have verified the transceivers being used are both receiving 3.3V

Any help would be greatly appreciated, Rus

Answer 1

您忘记启用“内部”CAN 中断：

    HAL_CAN_ActivateNotification(&hcan1, CAN_IT_RX_FIFO0_MSG_PENDING);

Answer 2

I am facing the same issues.. I have enabled both CAN interrupts transmission and reception.. however, it does not enter in CAN1_RX0_IRQHandler() anytime.. whereas CAN1_TX_IRQHandler() works fine! and also, i am able to see the data on the bus (verified using logic analyzer)

if (HAL_CAN_ActivateNotification(&hcan1, CAN_IT_RX_FIFO0_MSG_PENDING | CAN_IT_TX_MAILBOX_EMPTY) != HAL_OK)
{
/* Notification Error */
Error_Handler();
}