Sampling Service

The sampling service is useful when not all the discrete input state change needs to be captured, but only a snapshot (for display for example). The sampling logic keeps the last record.

When sampling discrete input signals, the use of one MXF_DISCRETE_SAMPREC structure is required.

The mxfDiscreteRxSamplingRead() function must be used to get the sampling data.

Example

The example below shows how a sampling application can collect discrete data values.

MXF_DISCRETE_SAMPREC sampRec;
HMXF_CHANNEL channel;                                 
HMXF_BUFFER  buffer;
uint64 count, byteCount, status;
uint32 i, rc = MAXT_SUCCESS;

   ...

   // Allocate the sampling buffer
   if(!rc)
      rc = mxfRxSamplingBufferAlloc(channel, sizeof(MXF_DISCRETE_SAMPREC), &buffer, NULL);

   // Set kill time at 1 sec.
  if (!rc)
    rc = mxfRxSamplingKilltimeSet(buffer, 1*1000*1000*1000);

   // Start sampling.
   if (!rc)
   {
     rc = mxfRxSamplingStart(buffer); 
      if (!rc)
       printf("Sampling started\n\r");
   }

   // Monitor sampling data - 2 secs: 20 times*100ms.
   for (i = 0; !rc && i < 20; i++)   
   {
      // Waits 100 ms
      mxfSleep(100);

      // Gets sampling data
      rc = mxfDiscreteRxSamplingRead(buffer, MXF_RXSAMPLING_FLAG_DEFAULT, 1, sizeof(MXF_DISCRETE_SAMPREC), &count, &byteCount, &sampRec);
      if (!rc)
      {
         if (count!=0)
         {   
            printf("Timetag %llu - data=0x%08x, edge=0x%08x\n", sampRec.timeTag, sampRec.data, sampRec.edge);
         }
      }
   }

   ...