From the last email it appears that CC2420 does provide snooping functionality, doesn't it?
If unfortunately, it does not, then how to snoop on micaz? Synchronous ACK is not necessary to us.
Really need help. Thanks a lot.
Tie
On 10/28/06, Tie Luo <[EMAIL PROTECTED]> wrote:
Thanks.But in CC2420ActiveMessageC, Snoop is wired to CC2420ActiveMessageP.snoop,and in CC2420ActiveMessageP, it has the following code:event message_t* SubReceive.receive(message_t* msg, void* payload, uint8_t len) {
if (call AMPacket.isForMe(msg)) {
return signal Receive.receive[call AMPacket.type(msg)](msg, payload, len - CC2420_SIZE);
}
else {
return signal Snoop.receive[call AMPacket.type(msg)](msg, payload, len - CC2420_SIZE);
}
}
where SubReceive is finally wired to CC2420ReceiveP.receive.In CC2420ReceiveP, it has the following code:if ( type == IEEE154_TYPE_DATA ) {
post receiveDone_task();
return;
}
and in receiveDone_task(), Receive.receive is signaled.All the above means that, no component seems to check the destination address unless CC2420ActiveMessageP. But this component does signal Snoop.Receive().So, why CC2420 is not able to snoop? And, I indeed do not need synchronous ACKs.Tie--On 10/28/06, Philip Levis <[EMAIL PROTECTED] > wrote:On Oct 27, 2006, at 10:13 PM, Tie Luo wrote:
> Dear all,
>
> I am using AMSnoopingReceiverC, but the node seems only receive
> message destined to the node itself, and cannot receive messages
> for others.
> I saw in CC2420ActiveMessageC.nc there is a comment:
> "Note that snooping may not work, due to CC2420 early packet
> rejection if acknowledgements are enabled."
> However when I check all relevant files like CC2420CsmaC.nc,
> CC2420CsmaP.nc, CC2420ReceiveC.nc, CC2420ReceiveP.nc, it appears
> that the snooping function does get fulfilled.
>
> So, does AMSnoopingReceiver really work on micaz? (TinyOS 2.x)
>
> Dr. Levis, you wrote that comment, may you help on this question?
> Many thanks!
>
You cannot snoop with the default T2 CC2420 stack. If you want to
snoop you have to disabled address decode, which means you do not get
synchronous acks.
Phil
Regards,
Tie
--
Regards,
Tie
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