[Tinyos-help] How to enableACK on tmote

[Ole Bischoff]

Hy Lee Ee Foong,

I never tried to read the ack element in my message before sending, but I successfully checked the
fcfhi element (after sending) from a received messages. 
fcfhi is the high byte of the FrameControlField (IEEE 802.15.4), if this is equal to 0x21 your message 
requests ACK.

You could make a check (on a receiving mote) like:

event TOS_MsgPtr ReceiveMsg.receive(TOS_MsgPtr _msg) {
    if (_msg->fcfhi & (1 << CC2420_DEF_FCF_BIT_ACK))    // with ACK
        call Leds.redToggle();
    else                                                // without ACK
        call Leds.greenToggle();
}


The condition of the if statement (_msg->fcfhi & (1 << CC2420_DEF_FCF_BIT_ACK))
checks bit number 5 of fcfhi, because this indicates a requested ACK (2^5=32=0x20).

The following defines can be found in CC2420Const.h:
CC2420_DEF_FCF_BIT_ACK 0x05  // bitposition in fcfhi
CC2420_DEF_FCF_HI      0x01  // without ACK
CC2420_DEF_FCF_HI_ACK  0x21  // with ACK


Regards,
            OLE

  ----- Original Message ----- 
  From: Lee Ee Foong 
  To: Tinyos-help at Millennium.Berkeley.EDU 
  Sent: Friday, November 03, 2006 5:11 AM
  Subject: [Tinyos-help] How to enableACK on tmote


  I'm trying to test the ack in the sendDone( ) but the ack field always set to zero. I call MacControl.enableACK( ) in the StdControl.start( ).  Is there something that I did wrong or missing?

  I wired the components as following:

   Main.StdControl -> CC2420RadioC;
   MultiHopEngineM.MacControl -> CC2420RadioC;

   command result_t StdControl.start()
    {
       call MacControl.enableAck();
       return SUCCESS;
    }


   event result_t SendMsg.sendDone[uint8_t id](TOS_MsgPtr pMsg, result_t success)
   {
      dbg(DBG_TEMP, "ack is %d \n", pMsg->ack);
   
      if (pMsg->ack == 1)
        call Leds.redToggle();
      else
        call Leds.greenToggle();
     
      return SUCCESS;
    }



   Thank you.

  Andre


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