AWR1843: CANFD Bus Off interrupts vs Bus Off protocol status

Could you tell us which application you are trying here?

And make sure that errInterruptEnable=1 and appErrCallBack callback function are provided in CANFD_MCANInitParams structure during CANFD_init driver function call.

Regards,

Jitendra

Hi Jitendra,

This is based on the demo application.  appErrCallBack is working properly for other errors (PROTCOL_ERR_DATA_PHASE and PROTOCOL_ERR_ARB_PHASE).  But when I get BUS_OFF state in the PSR register (which I can verify by calling CANFD_getOptions with CANFD_Option_MCAN_PROTOCOL_STATUS), I don't get the CANFD_Reason_BUSOFF error reason in my callback.  

Another question I have: if MCAN goes into BUS_OFF state in PSR, what is the correct way to teardown and re-initialize the MCAN/CANFD module?  

Thanks

Hi Jovial,

Let me discuss this internally and get back to you by this week to provide a solution for this CAN error issue.

Regards,

Jitendra

To recover from the BUSOFF mode , the MCAN IP need to be put in NORMAL/operation mode

static void MCANAppErrStatusCallback(CANFD_Handle handle, CANFD_Reason reason, CANFD_ErrStatusResp* errStatusResp)

{

    int32_t                 errCode;

    if(reason == CANFD_Reason_BUSOFF)

    {

        gErrStatusInt++;

        CANFD_BusOffRecovery(handle, &errCode);

    }

    return;

}

int32_t  CANFD_BusOffRecovery(CANFD_Handle handle,  int32_t* errCode)

{

    CANFD_DriverMCB*                ptrCanFdMCB;

    uint32_t                        baseAddr;

     int32_t                         retVal = 0;

    ptrCanFdMCB = (CANFD_DriverMCB*)handle;

    if ((ptrCanFdMCB == NULL) )

    {

        *errCode = CANFD_EINVAL;

        retVal = MINUS_ONE;

    }

    baseAddr = ptrCanFdMCB->hwCfg.regBaseAddress;

    /*Check if the busoff status and also the Error counter*/

    /* Put MCAN in opertional mode */

    MCAN_setOpMode(baseAddr, CANFD_MCANOperationMode_NORMAL);

    /* Wait while MCAN is not in operational mode. TODO add timeout */

    do

    {

    } while (MCAN_getOpMode(baseAddr) != CANFD_MCANOperationMode_NORMAL);

    return retVal;

}

Hi Jitendra,

Thank you for the detailed code snippet.  I will test it out on my side.

My other question still remains: is there a link between the MCAN_PSR Busoff bit and the MCAN_IR Bus off bit?  My understanding is the MCAN_IR is what triggers the MCAN callback function, so if the MCAN_PSR Busoff bit is set, will the MCAN_IR see Bus off set?

Best

Here is the figure snapshot for CAN interrupt tologoy (from AWR1843 TRM), where Bus-off interrupt is routed to DCAN0INT, so you it should arrive at error-callback function.

Regards,

Jitendra

Hi Jitendra,

Thank you for the reference.  Which TRM revision is this diagram from?  I can't find it in the revision E AWR1843 TRM (from this link https://www.ti.com/lit/pdf/swru520 on the AWR1843 product page).

Nevermind - I found this diagram in rev E, it is now Figure 22-13.  I will look at this section in more details and see if I can figure out why I cannot see the bus off interrupt.