Use case #1

In this use case, CAN0 mailbox 0 works in PRODUCER mode, and CAN1 mailbox 0 works in CONSUMER mode. While CAN1 mailbox 0 receives a data frame from the bus, an interrupt is triggered.

Setup steps

Prerequisites

• Power Management Controller driver
• CAN transceiver driver

Example code

Add to application C-file:

can_mb_conf_t can0_mailbox;
can_mb_conf_t can1_mailbox;
volatile uint32_t g_ul_recv_status = 0;

void CAN1_Handler(void)
{
    uint32_t ul_status;

    ul_status = can_mailbox_get_status(CAN1, 0);
    if ((ul_status & CAN_MSR_MRDY) == CAN_MSR_MRDY) {
        can1_mailbox.ul_mb_idx = 0;
        can1_mailbox.ul_status = ul_status;
        can_mailbox_read(CAN1, &can1_mailbox);
        g_ul_recv_status = 1;
    }
}

pmc_enable_periph_clk(ID_CAN0);
pmc_enable_periph_clk(ID_CAN1);

can_init(CAN0, ul_sysclk, CAN_BPS_1000K);
can_init(CAN1, ul_sysclk, CAN_BPS_1000K);

can_reset_all_mailbox(CAN0);
can_reset_all_mailbox(CAN1);

can0_mailbox.ul_mb_idx = 0;
can0_mailbox.uc_obj_type = CAN_MB_PRODUCER_MODE;
can0_mailbox.ul_id_msk = 0;
can0_mailbox.ul_id = CAN_MID_MIDvA(0x0b);
can_mailbox_init(CAN0, &can0_mailbox);

can0_mailbox.ul_datal = 0x11223344;
can0_mailbox.ul_datah = 0x44332211;
can0_mailbox.uc_length = 8;
can_mailbox_write(CAN0, &can0_mailbox);

can1_mailbox.ul_mb_idx = 0;
can1_mailbox.uc_obj_type = CAN_MB_CONSUMER_MODE;
can1_mailbox.uc_tx_prio = 15;
can1_mailbox.ul_id_msk = CAN_MID_MIDvA_Msk | CAN_MID_MIDvB_Msk;
can1_mailbox.ul_id = CAN_MID_MIDvA(0x0b);
can_mailbox_init(CAN1, &can1_mailbox);

can_enable_interrupt(CAN1, CAN_IER_MB0);
NVIC_EnableIRQ(CAN1_IRQn);

Workflow

1. Define the CAN0 and CAN1 Transfer mailbox structure:

   • can_mb_conf_t can0_mailbox;
     can_mb_conf_t can1_mailbox;

2. Define the receive flag that is changed in CAN1 ISR handler:

   • volatile uint32_t g_ul_recv_status = 0; 

3. Define the CAN1 ISR handler in the application:

   • void CAN1_Handler(void); 

4. In CAN1_Handler(), get CAN1 mailbox 0 status:

   • ul_status = can_mailbox_get_status(CAN1, 0); 

5. In CAN1_Handler(), check whether the mailbox 0 has received a data frame:

   • if ((ul_status & CAN_MSR_MRDY) == CAN_MSR_MRDY) {
         can1_mailbox.ul_mb_idx = 0;
         can1_mailbox.ul_status = ul_status;
         can_mailbox_read(CAN1, &can1_mailbox);
         g_ul_recv_status = 1;
     }

6. In CAN1_Handler(), if mailbox 0 is ready, read the received data from CAN1 mailbox 0:

   • can1_mailbox.ul_mb_idx = 0;
     can1_mailbox.ul_status = ul_status;
     can_mailbox_read(CAN1, &can1_mailbox);

7. In CAN1_Handler(), if mailbox 0 is ready, set up the receive flag:

   • g_ul_recv_status = 1; 

8. Enable the module clock for CAN0 and CAN1:

   • pmc_enable_periph_clk(ID_CAN0);
     pmc_enable_periph_clk(ID_CAN1);

9. Initialize CAN0 and CAN1, baudrate is 1Mb/s:

   • can_init(CAN0, ul_sysclk, CAN_BPS_1000K);
     can_init(CAN1, ul_sysclk, CAN_BPS_1000K);

   • Note

     The CAN transceiver should be configured before initializing the CAN module.

10. Reset all CAN0 and CAN1 mailboxes:

    • can_reset_all_mailbox(CAN0);
      can_reset_all_mailbox(CAN1);

11. Initialize CAN0 mailbox 0 as PRODUCER:

    • can0_mailbox.ul_mb_idx = 0;
      can0_mailbox.uc_obj_type = CAN_MB_PRODUCER_MODE;
      can0_mailbox.ul_id_msk = 0;
      can0_mailbox.ul_id = CAN_MID_MIDvA(0x0b);
      can_mailbox_init(CAN0, &can0_mailbox);

12. Prepare the response information when it receives a remote frame:

    • can0_mailbox.ul_datal = 0x11223344;
      can0_mailbox.ul_datah = 0x44332211;
      can0_mailbox.uc_length = 8;
      can_mailbox_write(CAN0, &can0_mailbox);

13. Initialize CAN1 mailbox 0 as CONSUMER:

    • can1_mailbox.ul_mb_idx = 0;
      can1_mailbox.uc_obj_type = CAN_MB_CONSUMER_MODE;
      can1_mailbox.uc_tx_prio = 15;
      can1_mailbox.ul_id_msk = CAN_MID_MIDvA_Msk | CAN_MID_MIDvB_Msk;
      can1_mailbox.ul_id = CAN_MID_MIDvA(0x0b);
      can_mailbox_init(CAN1, &can1_mailbox);

14. Enable the CAN1 mailbox 0 interrupt:

    • can_enable_interrupt(CAN1, CAN_IER_MB0);
      NVIC_EnableIRQ(CAN1_IRQn);

Usage steps

Example code

can_global_send_transfer_cmd(CAN0, CAN_TCR_MB0);
can_global_send_transfer_cmd(CAN1, CAN_TCR_MB0);

while (!g_ul_recv_status) {
}

Workflow

1. Enable CAN0 mailbox 0 to receive remote frame and respond it:

   • can_global_send_transfer_cmd(CAN0, CAN_TCR_MB0); 

2. Enable CAN1 mailbox 0 to send out a remote frame and then receive data frame from bus:

   • can_global_send_transfer_cmd(CAN1, CAN_TCR_MB0); 

3. Wait for the communication to be completed.

   • while (!g_ul_recv_status) {
     }