CC2652R: Issue about ZDP_TmpBuf size in ZDP_ParentAnnce

The perfect solution is like this

#define ZDP_BUF_SZ          82 //80

...


afStatus_t ZDP_ParentAnnce( uint8_t *TransSeq,
                            zAddrType_t *dstAddr,
                            uint8_t numberOfChildren,
                            uint8_t *childInfo,
                            cId_t clusterID,
                            uint8_t SecurityEnable )
{
  uint8_t *pBuf = ZDP_TmpBuf;
  ZDO_ChildInfo_t *pChildInfo;
  uint8_t i, len;
  uint8_t *numOfChild;
  uint8_t maxParentAnnceChild = MAX_PARENT_ANNCE_CHILD; //luoyiming fixed at 2020-02-27

  (void)SecurityEnable;  // Intentionally unreferenced parameter

  pChildInfo = (ZDO_ChildInfo_t *)childInfo;

  if ( dstAddr->addrMode == AddrBroadcast )
  {
    // Make sure is sent to 0xFFFC
    dstAddr->addr.shortAddr = NWK_BROADCAST_SHORTADDR_DEVZCZR;
  }
  len = 1;
  if ( clusterID == Parent_annce_rsp )
  {
    // + Status Byte
    len += 1;
    // Set the status bit to success
    *pBuf++ = 0;
    // 79 byte of ZDP_TmpBuf is not enough, fixed by luoyiming 2020-02-27
    maxParentAnnceChild -= 1;
  }

  numOfChild = pBuf;
  *pBuf++ = numberOfChildren;

  for ( i = 0; i < maxParentAnnceChild; i++ )
  {
    pBuf = osal_cpyExtAddr( pBuf, pChildInfo[childIndex].extAddr );
    childIndex++;

    len += Z_EXTADDR_LEN;

    if ( childIndex == numberOfChildren )
    {
      pBuf = numOfChild;
      *pBuf = i + 1;
      // All childs are taken, restart index and go out
      childIndex = 0;
      return fillAndSend( TransSeq, dstAddr, clusterID, len );
    }
  }

  pBuf = numOfChild;
  *pBuf = maxParentAnnceChild;
  if ( childIndex < numberOfChildren )
  {
    if ( clusterID == Parent_annce )
    {
      ZDApp_SetParentAnnceTimer();
    }
    if ( clusterID == Parent_annce_rsp )
    {
      OsalPortTimers_startTimer( ZDAppTaskID, ZDO_PARENT_ANNCE_EVT, 10 );
    }
  }

  return fillAndSend( TransSeq, dstAddr, clusterID, len );
}

——————

The MTU of AF-Broadcast frame is 82-Byte, so ZDP_BUF_SZ  can be set only in 82-byte.

The Parent_annce frame carries 1-Byte ZDP_Sequence, 1-Byte "numChildren". And 80-byte left space can carries 10 IEEE-address.

The Parent_annce_rsp frame carries 1-Byte ZDP_Sequence, 1-Byte "status byte", 1-Byte "numChildren". And 79-byte left space can only carries 9 IEEE-address.

I agree with you. I just want TI to check and confirm it.

The Maximum size of broadcast frame is 82 byte. So the best way is to cut down the number of children in one frame of parent-announce-response command.

Good point Aries!

The only broadcast in this case is Parent Annce, which uses:
- 1 byte for TransSeq
- 1 byte for NumberOfChildren
- 80 bytes left for children --> up to 10 children

However, that Parent Annce Rsp is a unicast, so a payload larger than 82 bytes is possible (but not "pretty", since it will be fragmented).

A good compromise (to avoid fragmentation) may be as you mentioned, to set the buffer size to 82 and reduce the number of children in both Parent Annce and Parent Annce Rsp to 9.
I'll pass this along as well.

Thanks Aries and Toby.