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CANSTMOB &= ~_BV(AERR) ;

CANSTMOB = 0;

INTERRUPT CAN IT () {       // Use the correct syntax for your embedded compiler.
    unsigned char save_page;    // Pre­interrupt CANPAGE value storage.
    unsigned char mob;          // Temporary MOb number value.
    unsigned char isr_flags;    // Temporary interrupt flags value.

    save_page = CANPAGE;        // Save the pre­interrupt CANPAGE value.

        // CANGIE ENTX, ENRX and ENERR in can_init() enables the MOb interrupt
        //  CAMSTMOB flags that CANSIT and CANHPMOB will respond to.
        // Only use CANPAGE = CANHPMOB one time for each MOb while loop.
        // See CANHPMOB.CGPn bits for initial CANPAGE AINC and INDX values.
        // See CANHPMOB.HPMOBn bits description for the reason 0xF0 is used.
        // The CANSIT.SITn bit must be set for CANHPMOB to select that MObn value.
    while ((CANPAGE = CANHPMOB) < 0xF0) {

            // Extract the MOb number value of the MOb being processed.
        mob = (CANPAGE >> MOBNB0);
        isr_flags = CANSTMOB;         // Save the MOb interrupt flags state.
            // Clear the MOb interrupt flags when you process each MOb. This also
            // clears the read only CANSIT.SITn bit for this MOb number n (now
            // CANHPMOB will ignore this MOb when the CANSIT.SITn bit is cleared).
        CANSTMOB = 0;                 // Immediately clear the flags.

        // ******* process this active CANSTMOB interrupt MOb number *******
            // isr_flags error bits set means its CANEN.ENMOBn bit is still set
            //  unless the MOb was deliberately disabled (CANCDMOB.CONMOB=0),
            //  aborted (ABRQ=1) or standby mode (ENASTB=0) was applied. None of the following
            //  MOb registers have any useful values during isr_flags errors.
            // isr_flags TXOK bit is set for a Tx and CANEN.ENMOBn bit is cleared.
            // isr_flags RXOK bit is set for a Rx and CANEN.ENMOBn bit is cleared.
            // CANSTM.TIMSTMn bits have the Rx or Tx time stamp value.
            // CANIDT.RTRTAG bit has the actual Rx Data or Remote frame type.
            // CANCDMOB.IDE bit has the actual Rx 11 bit or 29 bit format type.
            // CANIDT.IDTn bits have the actual Rx message identifier value.
            // (CANIDT.IDTn bits >> 21) = 11 bit format unsigned integer ID value.
            // (CANIDT.IDTn bits >> 3) = 29 bit format unsigned long ID value.
            // CANCDMOB.DLC bits have the actual Rx DLC count value.
            // isr_flags DLCW bit warns you if CANCDMOB.DLC was changed by a Rx.
            // CANMSG bytes have the Rx CAN data (up to DLC, only for Data Frame).
            //  If you read any Rx CANMSG bytes always use CANCDMOB.DLC field for
            //  the actual number of CANMSG bytes to read. However, if DLC is over
            //  a value of 8, your software must treat this as a value of 8 (this
            //  is also what the CAN hardware does if a bad DLC is received).
            // CANPAGE.INDX points at each CANMSG byte when you read or write
            //  CANMSG (see CANPAGE.AINC for INDX automatic increment info).
            // If CANEN.ENMOBn==0 this MOb task life cycle is now complete.
    } // ===> end of the while(CANHPMOB) MOb processing loop <===

        // CANGIE in can_init() selects the enabled General interrupt flags.
        // First save and then clear the general interrupt flags.
    isr_flags = CANGIT;         // Save the current general interrupt flags state.
        // OVRTIM does not belong to this CAN IT interrupt vector.
        // Using isr_flags instead of CANGIT prevents clearing any new interrupts.
        // Clear only the General interrupt flags that will be processed next.
    CANGIT = isr_flags & ~(1 << OVRTIM);

    // ***** process all enabled general CANGIT interrupts using isr_flags *****
    // An example of using isr_flags instead of CANGIT would be:
    //  if (isr_flags & (1 << BOFFIT)) - CANGIT is not used since it was cleared.

    CANPAGE = save_page;        // Restore the pre­interrupt CANPAGE value.
}

/* when (isr_flags TXOK bit is set and CANCDMOB.RPLV bit was never set)
       CANSTM.TIMSTM is the only MOb register that has new info.
   when (isr_flags RXOK bit is set)
       CANSTM.TIMSTM has new info.
       if (CANIDM4.IDEMSK bit is cleared)
           CANCDMOB.IDE bit may have new info.
           CANCDMOB.IDE type is required to read CANIDM and CANIDT
       if (any CANIDM.IDMSKn bits are zero values, depends on IDE type)
           corresponding CANIDT.IDTn bits may have new info., depends on IDE type
       if (CANIDM4.RTRMSK bit is cleared)
           CANIDT4.RTRTAG bit may have new info.
       if (isr_flags DLCW bit is set)
           CANCDMOB.DLC has new info. (always limit DLC values to 8 maximum)
       if (CANIDT4.RTRTAG bit is cleared ­ i.e. data frame)
           There are new CANMSG bytes of CANCDMOB.DLC number of bytes (0 to 8 bytes)
*/