About the use of CAN1_RX0_IRQn and CAN1_RX1_IRQn in STM32

    "If you use CAN pins PA11 and PA12, use CAN1_RX0_IRQn for receive interrupts. If CAN pins PB8 and PB9 are used, that is, redefined pins, use CAN1_RX1_IRQn for receive interrupts. Since PA11 and PA12 are also USB pins, the library file for non-interconnected microcontrollers with CAN controllers uses USB_LP_CAN1_RX0_IRQn when naming them."

   The above content is referenced from the Internet. It has been confirmed that the above statement is incorrect for the following reasons:

    STM32 has two 3-level deep receive buffers: FIFO0 and FIFO1. Each FIFO can store 3 complete messages, which are completely managed by hardware. If the receive interrupt comes from FIFO0, it is processed by CAN1_RX0_IRQn interrupt. If the receive interrupt comes from FIFO1, it is processed by CAN1_RX1_IRQn interrupt. During the initialization configuration of CAN, use CAN_FilterFIFOAssignment to select the FIFO to use.

Here is an example:

1. Configure the filter
 CAN_FilterInitStructure.CAN_FilterNumber = 0;

 CAN_FilterInitStructure.CAN_FilterMode = CAN_FilterMode_IdMask;

   CAN_FilterInitStructure.CAN_FilterScale = CAN_FilterScale_32bit;

 CAN_FilterInitStructure.CAN_FilterIdHigh = 0x0000;

 CAN_FilterInitStructure.CAN_FilterIdLow = 0x0000;

 CAN_FilterInitStructure.CAN_FilterMaskIdHigh = 0x0000; 
 
 CAN_FilterInitStructure.CAN_FilterMaskIdLow = 0x0000;

 CAN_FilterInitStructure.CAN_FilterFIFOAssignment = 0;   //关联FIFO0

 CAN_FilterInitStructure.CAN_FilterActivation = ENABLE;

 CAN_FilterInit(&CAN_FilterInitStructure);

 
 CAN_FilterInitStructure.CAN_FilterNumber = 14;

 CAN_FilterInitStructure.CAN_FilterFIFOAssignment = 1;   //关联FIFO1

 CAN_FilterInit(&CAN_FilterInitStructure);

 

2. Enable CAN interrupt

   /* IT Configuration for CAN1 */  

   CAN_ITConfig(CAN1, CAN_IT_FMP0, ENABLE);

   CAN_ITConfig(CAN1, CAN_IT_FMP1, ENABLE);
 

   /* IT Configuration for CAN2 */  

   CAN_ITConfig(CAN2, CAN_IT_FMP0, ENABLE);

   CAN_ITConfig(CAN2, CAN_IT_FMP1, ENABLE);

 

3. Interrupt handling function

void CAN1_RX0_IRQHandler(void)

{
        CAN_Receive(CAN1, CAN_FIFO0, &CAN1_RxMsg);

 //
}

void CAN1_RX1_IRQHandler(void)

{
        CAN_Receive(CAN1, CAN_FIFO1, &CAN1_RxMsg);

        //
}

void CAN2_RX0_IRQHandler(void)

{

        CAN_Receive(CAN2, CAN_FIFO0, &CAN2_RxMsg);
       //
}

void CAN2_RX1_IRQHandler(void)

{
        CAN_Receive(CAN2, CAN_FIFO1, &CAN2_RxMsg);
        //
}