Periodic Frame Service

The transmission channels of A629 modules support this service (logical channel 1 to 120).

Refer to the MXF_A629_TXPERIODIC_MJRFRAME_MSG structure for major frame building.

The major frame (XPP) can contain up to 31 minor frames (messages) and a total of 31 messages (wordstrings).

The minor frame rate is taken from the module TI value.

Each element of the major frame corresponds to the MXF_A629_TXPERIODIC_MJRFRAME_MSG structure. It contains the label to be sent, the length of the wordstring, and other options.

Before setting the major frame, it is suggested to clear it using the mxfTxPeriodicMajorFrameClear() function.

The minor frame can then be set using the mxfA629TxPeriodicMajorFrameSet() function. By default, the major frame is empty.

To set the data associated to the label, refer to the Periodic Update Message Service section.

Building a major frame:

• Clear the major frame (refer to mxfTxPeriodicMajorFrameClear() function).
• Allocate the Periodic Update Message buffer. (refer to the mxfTxPeriodicUpdateMsgBufferAlloc() function).
• Set minor frame #0, #1, etc (refer to mxfA629TxPeriodicMajorFrameSet() function).
• Set the default data of each wordstring. By default, all wordstrings are set to zero. (refer to the mxfA629TxPeriodicUpdateMsgWrite() function).
• Start the Major Frame with the desired mode (block or independent). (refer to the mxfA629TxPeriodicMajorFrameStart() function).
• Update the data of each wordstring when desired. (refer to the mxfA629TxPeriodicUpdateMsgWrite() and mxfTxPeriodicUpdateMsgBufferStatusGet() functions).

#define MAX_TX_RECORDS_TO_TRANSMIT 1
#define TX_BUFFER_SIZE     MAX_TX_RECORDS_TO_TRANSMIT*sizeof(MXF_A629_DATAREC)

HMXF_SERVER server;
HMXF_CHANNEL txChannel;
MXF_A629_TXPERIODIC_MJRFRAME_MSG minorFrame[3];
HMXF_BUFFER  txBuffer[6]={0,0,0,0,0,0};
MXF_A629_TXPERIODIC_MJRFRAME_PROPERTIES majorProperties;
MXF_A629_DATAREC txRec629;
uint64 index;

   ...

   // Sets timebase to RTC nsec
   if(!rc)
      rc = mxfSystemTimeBaseSet(server, MXF_TIMEBASE_DEVICE_NSEC);

   // Allocates buffer for tx data
   if(!rc)
   {
      // Allocate six TX Periodic Update Message buffer
      for(index=0; index<6 && !rc; index++)
         rc = mxfTxPeriodicUpdateMsgBufferAlloc(txChannel, index, TX_BUFFER_SIZE, &txBuffer[index], NULL);
   }

   // Clears the major frame
   if(!rc)
      rc = mxfTxPeriodicMajorFrameClear(rt, 0);

   // Sets the minor frame #0 using 3 WordStrings
   if(!rc)
   {
      memset(minorFrame, 0, sizeof(minorFrame));

      //WordString #0 : Label 0x1, CID 0x4
      minorFrame[0].buffer  = txBuffer[0];
      minorFrame[0].label   = 0x1;
      minorFrame[0].cid     = 0;
      minorFrame[0].length  = 1;

      //WordString #1 : Label 0x2, CID 0x4
      minorFrame[1].buffer  = txBuffer[1];
      minorFrame[1].label   = 0x2;
      minorFrame[1].cid     = 0;
      minorFrame[1].length  = 2;

      //WordString #2 : Label 0x3, CID 0x4
      minorFrame[2].buffer  = txBuffer[2];
      minorFrame[2].label   = 0x3;
      minorFrame[2].cid     = 0;
      minorFrame[2].length  = 3;

      rc = mxfA629TxPeriodicMajorFrameSet(txChannel, 0, 0, 3, minorFrame);
   }

   //--- Set the minor frame #1 with 2 WordStrings --//
   if(!rc)
   {
      //WordString #0 : Label 0x4, CID 0x4
      minorFrame[0].buffer  = txBuffer[3];
      minorFrame[0].label   = 0x4;
      minorFrame[0].cid     = 0;
      minorFrame[0].length  = 4;
      minorFrame[0].options = MXF_A629_TXPERIODIC_MJRFRAME_MSG_OPT_CRC_ENABLE;

      //WordString #1 : Label 0x5, CID 0x4
      minorFrame[1].buffer  = txBuffer[4];
      minorFrame[1].label   = 0x5;
      minorFrame[1].cid     = 0;
      minorFrame[1].length  = 5;
      minorFrame[1].options = MXF_A629_TXPERIODIC_MJRFRAME_MSG_OPT_CRC_ENABLE;

      rc = mxfA629TxPeriodicMajorFrameSet(txChannel, 0, 1, 2, minorFrame);
   }   

   //--- Set default data for label 0x1, CID 0x4 ---//
   if(!rc)
   {
      memset(&txRec629, 0, sizeof(txRec629));

      txRec629.control     = 0;
      txRec629.repeatCount = 1;
      txRec629.dataSize    = 4;
      txRec629.data[0] = 0;
      txRec629.data[1] = 0x1111;
      rc = mxfA629TxPeriodicUpdateMsgWrite(txBuffer[0], 1, &txRec629);
   }

   //--- Set default data for label 0x2, CID 0x4 ---//
   if(!rc)
   {
      txRec629.control     = 0;
      txRec629.repeatCount = 1;
      txRec629.dataSize    = 6;
      txRec629.data[0] = 0;
      txRec629.data[1] = 0x2222;
      txRec629.data[2] = 0x2222;
      rc = mxfA629TxPeriodicUpdateMsgWrite(txBuffer[1], 1, &txRec629);
   }   

   //Start the major frame in the Block mode
   if(!rc)
   {
      majorProperties.mode = MXF_A629_TXPERIODIC_MJRFRAME_PROPERTIES_MODE_BLOCK;
      majorProperties.reserved = 0;
      rc = mxfA629TxPeriodicMajorFrameStart(txChannel, 0, 0, &majorProperties);
   }

   ...

   // Stops the major frame
   if(!rc)
      rc = mxfTxPeriodicMajorFrameStop(txChannel, 0, 0);

   if(!rc)
      rc = mxfTxPeriodicMajorFrameClear(txChannel, 0);

  ...

Note

If two wordstrings with the same buffer are close to each other in the minor frame, it can happen that the firmware doesn't have the time to update the buffer before the next occurrence of the wordstring is sent, so the same data will be sent twice. If they need to have different data, simply assign a different buffer to one of the wordstring and update both buffers individually.