CAN RX Interrupt Configuration : AM3517

Dear All,

I have configured the Receive interrupt for CAN.

Flow of Program :

1. Initialise CAN .

2. Setup Transmit/Receive Mailbox.

3. I have configured Mailbox 1 as transmit ..MID 0x15AC0000..Data Length : 4.

4.Mailbox 0 as Receive Mailbox. MID 0x1CA00000..Data Length  : 4.

5. I am using transmit function to transmit data :

uint32_t CAN_transmit(uint8_t mailbox, uint8_t *data, uint8_t length)
{
   uint32_t mask = 1 << mailbox;
   uint8_t i;
   uint32_t begin_time;
   
   debug_print("In TXXXXXXXXXXX");

   // verify we're not exceeding our set length
   if (length > (CANMCF(mailbox) & 0xF))
   {
      return (ERR_INVALID_PARAMETER);
   }

   for (i=0; i < length && i < 4; i++)
   {
      OUT_REGL(CANMDL(mailbox), (IN_REGL(CANMDL(mailbox)) << 8));
      SETBIT_REGL(CANMDL(mailbox), data[i]);
   }

   for (; i < 4; i++)
   {
      OUT_REGL(CANMDL(mailbox), (IN_REGL(CANMDL(mailbox)) << 8));
   }

   for (; i < length && i < 8; i++)
   {
      OUT_REGL(CANMDH(mailbox), (IN_REGL(CANMDH(mailbox)) << 8));
      SETBIT_REGL(CANMDH(mailbox), data[i]);
   }

   for (; i < 8; i++)
   {
      OUT_REGL(CANMDH(mailbox), (IN_REGL(CANMDH(mailbox)) << 8));
   }

   // send the message!
   SETBIT_REGL(CANTRS, mask);

   // wait for transmission ack
   begin_time = USTIMER_get();
   while (!CHKBIT_REGL(CANTA, mask)
            && ((USTIMER_get() - begin_time) < CAN_TIMEOUT_US));         
   if (!CHKBIT_REGL(CANTA, mask))
   {

     // Timeout occurred
      return ERR_FAIL;
   }
   debug_print("Fun CANTA %x\n",IN_REGL(CANTA));       
   // clear transmission ack so we can send again
   SETBIT_REGL(CANTA, mask);    //copied to ISr
   begin_time = USTIMER_get();
   while (CHKBIT_REGL(CANTA, mask)
            && ((USTIMER_get() - begin_time) < CAN_TIMEOUT_US));                
   if (CHKBIT_REGL(CANTA, mask))
   {    
      return ERR_FAIL;
   }

   return (ERR_NO_ERROR);
}

After transmitting the handler Goes to IRQ24_Handler : SECC0_INT interrupt Line.

The CANGIF0 : register Shows value : 0xC000 : Two interrupt have been occured one is GMIF0 : Transmission Over and other is AAIF0..transmission aborted. I am transmitting only once. Not able to understand why two interrupts are raised at a time. the Processor goes twice in the Service routine. first time i receive the Exact data..but the data received on second interrupt gets corrupted. I think i am missing some interrupt Clearing Register . Need Expertise view on this

Thanks and reagrd's

Hrishikesh.