How long will CSMA & Data-Poll waiting cost?

Hello Aries,

The CSMA is implemented as per the 802.15.4 specification in Z-Stack. On an average a good number for CSMA-CA will be about ~1msec. 

The end device after it receives the MAC ACK with pending bit set can wait upto ~19msec according to the IEEE 802.15.4 spec,. Yes, the parent will send the data using the CSMA-CA. 

Hope this helps. 

Regards

As my understanding that follow Ur discrib discribing,the EndDevice will stay in Rx-On status for 1~19ms by random(that meaning by luck,and bad-luck will cost 19ms*28mA power).

By I have test on Osilloscope.When a EndDevice receives the MAC ACK of Data-Poll,and the Parent FFD have no data to send to EndDevice,the EndDevice will sleep as soon as quick.

Yes,I have found Ack-Pending bit can be control by PENDING_OR bit of  FRMCTRL1.

But I have found another question,the "MAC_RADIO_TX_ACK_PEND" is set at rxStartIsr.When this status,CC2530 have only received 6 bytes(read 4bytes),that can't  judge what this packet is.It only can be judged this packet's type.

    if( MAC_FRAME_TYPE(&rxBuf[1]) == MAC_FRAME_TYPE_COMMAND )
    {
      if( macRxCheckMACPendingCallback())
      {
        /* Check is any mac data pending for end devices */
        ackWithPending = MAC_RX_FLAG_ACK_PENDING;
      }
      else
      {
        if( macSrcMatchIsEnabled )
        {
          /* When autopend is enabled, check if allpending is set to true */
          if( MAC_SrcMatchCheckAllPending() == MAC_AUTOACK_PENDING_ALL_ON )
          {
            ackWithPending = MAC_RX_FLAG_ACK_PENDING;
          }
        }
        else
        {
          /* When autopend is disabled, check the application pending callback */
          if( macRxCheckPendingCallback() )
          {
            ackWithPending = MAC_RX_FLAG_ACK_PENDING;
          }
        }
      }
    }

    if( ackWithPending == MAC_RX_FLAG_ACK_PENDING )
    {
      MAC_RADIO_TX_ACK_PEND();
    }
    else
    {
      MAC_RADIO_TX_ACK();
    }


    /* request a callback to macRxAckTxDoneCallback() when the ACK transmit has finished */
    MAC_RADIO_REQUEST_ACK_TX_DONE_CALLBACK();
    HAL_EXIT_CRITICAL_SECTION(s);
  }

Like these code,I feel that the once FFD receive RFD's CMD type packet,it will enable  PENDING_OR bit.

Then,I have found under code in "rxFcsIsr".

    if ((pRxBuf->internal.flags & MAC_RX_FLAG_ACK_PENDING) && (*pRxBuf->msdu.p != MAC_DATA_REQ_FRAME))
    {
      /* For non-data request commands, cancel the pending bit in the ACK. */
      MAC_RADIO_TX_ACK();
    }

but,I can,t understand this logic is wrong.If the received packet is MAC_DATA_REQ,but FFD have no data to this RFD,the "&&" should be "||".