Error Injection

The normal usage of the aperiodic / periodic services is to send accurate data on the data bus. However, for testing purposes, a facility is needed to send erroneous data on the bus. This functionality allows an application to test if the receiving LRU can recover properly from transmission errors.

The MXF_A708_DATAREC.control field can be used for injection of errors on the data-bus.

Example

The following code shows how to inject errors using the ARINC 708 record control property.

ar708_tx_error_injection.c

#define MAX_TX_RECORDS_TO_TRANSMIT    10

uint32 rc=0;
MXF_A708_DATAREC *txHostBuffer=NULL;
MXF_A708_DATAREC *rec=NULL;
uint64 data, word;

   ...

   if(!rc)
   {
      rec = txHostBuffer;
      //Prepare records to send with an error injection in transmission for the 3rd record
      for(data=0; data<MAX_TX_RECORDS_TO_TRANSMIT; data++)
      {
         rec->timeTag = 0;
         if (data==2)
         {
            rec->control = MXF_A708_TX_REC_CTRL_MANCHESTERBIT_ERROR;    //The 3rd record contains manchester error at bit 1000
            rec->manchesterBitErr = 1000;
         }
         else
         {
            rec->control = 0;
            rec->manchesterBitErr = 0;
         }
         rec->repeatCount = 1;
         rec->dataSize = 200;  //200 bytes corresponds to 1600 bits (see ARINC 708 specification)
         for(word=0; word < rec->dataSize/2; word++)     //The first 8 bits of each message have to be 0xB4
         {
            switch(word)
            {
            case 0:
               rec->data[word] = 055;
               break;
            case 1:
            case 2:
            case 3:
            case 4:
               rec->data[word] = 0x0000;
               break;
            default:
              rec->data[word] = (uint16)(0x0101*word);
            }
         }
         rc = mxfA708NextDataRecordPtrGet(rec, &rec);
      }
   }

   if(!rc)
   {
      printf("Transmitting ...\n");
      // Transmits strings on relative record time
      rc = mxfA708TxAperiodicWrite(txBuffer, MXF_TXAPERIODIC_FLAG_DEFAULT, 0, MAX_TX_RECORDS_TO_TRANSMIT, txHostBuffer);
   }

   ...