Basic RAW mode acquisition

When an AFDX channel is allocated in raw mode a calling application receives the data directly from a physical port (Port-A or Port-B).

The way the channel is allocated is described below;

• A physical channel must be obtained using the mxfModuleChannelGet() function or with the mxfModuleChannelAllGet() function by specifying the MXF_SCLASS_ALL subclass.
• The acquisition buffer must be allocated using the mxfRxAcqBufferAlloc() function.
• The acquisition mode can be set using the mxfRxAcqModeSet() function.
  
  Two modes of acquisition are defined;
  
  

  Condition	Description
  MXF_RXACQ_MODE_LINEAR	In this mode the acquisition stops when the buffer is full.
  MXF_RXACQ_MODE_CIRCULAR	In this mode the acquisition buffer is circular and never stops receiving. Whenever the acquisition queue becomes full, the acquisition process will discard the newest received record.

• The acquisition must be started using the mxfRxAcqStart() function.
• A read loop can be implemented using the mxfA664RxAcqRead() function.

The MXF_A664_DATAREC structure must be used for reading an ARINC 664 message with acquisition service.

Example

ar664_raw_rx.c
The example below shows how to implement an ARINC 664 basic receive acquisition application using a Raw port.

#define DATARECS_BUFFER_SIZE_MAX      64*1024

HMXF_CHANNEL phyChn = 0;
MXF_A664_DATAREC* rec664 = NULL;
MXF_A664_DATAREC* recPtr;
HMXF_BUFFER rxBuffer = 0;
uint64 usedBytes, freeBytes;
uint64 status, msgsCount, bytesCount;
uint64 recordIdx, dataIdx;
uint32 dataSize;

  ...

   // In RAW mode the acquisition buffer gets the data 
   // directly from the physical port. This port handle 
   // is used for acquisition and no COM/SAP port is required.
   // In this mode the application will read all the physical 
   // frames received on the port.
   if (!rc)
      rc = mxfRxAcqBufferAlloc(phyChn, 20000, &rxBuffer, NULL);

   if (!rc)
   {
      rec664 = malloc(DATARECS_BUFFER_SIZE_MAX);
      memset(rec664, 0, DATARECS_BUFFER_SIZE_MAX);
      if (!rec664)
         rc = MAXT_ERROR_MEM;
   }

   // Set acquisition mode
   if (!rc)
      rc = mxfRxAcqModeSet(rxBuffer, MXF_RXACQ_MODE_LINEAR);

   // Start acquisition, check status
   if (!rc)
      rc = mxfRxAcqStart(rxBuffer, MXF_RXACQ_FLAG_DEFAULT, 0, 0);

   if (!rc)
   {
      rc = mxfRxAcqBufferStatusGet(rxBuffer, &status, &msgsCount, &usedBytes, &freeBytes);
      if (!rc && (status & MXF_RXACQ_STATUS_RUNNING))
         printf("Acquisition Running\n\n");
   }

   ...

   // Read and display records
   rc = mxfA664RxAcqRead(rxBuffer, 0, DATARECS_BUFFER_SIZE_MAX, &status, &msgsCount, &bytesCount, rec664);
   if (!rc)
      printf("%llu records received\n\n", msgsCount);

   recPtr = rec664;
   for (recordIdx = 0; recordIdx < msgsCount && !rc; recordIdx++)
   {
      printf("  %03llu: timeTag=%012llu, Size=%u", recordIdx, recPtr->timeTag, recPtr->dataSize);
      printf("\n        data=");

      dataSize = recPtr->dataSize;

      for (dataIdx = 0; dataIdx < dataSize; dataIdx++)
      {
         printf("%02X ", recPtr->data[dataIdx]);

         if (!((dataIdx + 1) % 8) && (dataIdx + 1 < recPtr->dataSize))
            printf("\n             ");
      }

      printf("\n\n");

      mxfA664NextDataRecordPtrGet(recPtr, &recPtr);
   }

   ...