Hi Mischa - CC2420Transmit.resend(FALSE) will resend whatever has been previously loaded into the TXFIFO on the CC2420, without using clear channel assessments. This is one of the fastest methods of repetitively transmitting a single packet on the CC2420, and is what the low power listening implementation uses to wake up other nodes.
The CC2420 receiver will detect each packet separately and present those packets to CC2420Receive. Higher up, the UniqueReceive layer of the radio stack will filter out duplicate packets based on their DSN and source address information. If you want to actually receive the duplicate packet, you'll need to connect directly to CC2420ReceiveC and intercept it there. If it makes it easier on your implementation, send a packet using low power listening to the broadcast address. Tell the LowPowerListening interface before send that the receiver's rx sleep interval is, say... 10 minutes. YThen, LPL will do all the transmitting of that single packet for you as fast as it possibly can for 10 full minutes (you'll hit send and the sendDone will occur 10 minutes later). Of course, you can modify the DefaultLplP implementation on your machine if you want to see when it's calling resend(). -David -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Mischa Weise Sent: Wednesday, July 25, 2007 1:23 PM To: [email protected] Subject: [Tinyos-help] CC2420 send / resend context: ******** I want to find out, how fast I can broadcast packets with the CC2420 Radio on the Tmote platform (under the newest TinyOS-2.x from cvs). Therefore I send a packet burst of the same packet and measure the time at the sender (send->sendDone-event) and at a receiver(receive-event or SFDpinUp->SFDpinDown). My implementation is working if I use AMSend for every single packet of the burst. But now I want to make it faster and use CC2420Transmit.resend(...) Actually, I don't care about seq-no. or acks. (all acks turned off anyway). I just want the receiver to get the payload of any broadcasted package. questions: ********* Can I just use AMSend.send(AM_BROADCAST_ADDR, &pkt, paylen) and than use CC2420Transmit.resend(FALSE) as long as I want to resend the packet at &pkt? (to generate a packet burst of that packet) And will the CC2420 detect each packets separately? Or will it detect only the first such package and then discard all the following? (There are obviously different meanings of "detect": SFD pin behavior, TinyOS CC2420 behavior, TinyOS ActiveMessage behavior) Thank you in advance for any answers, clues, pointers to instruction. M. _______________________________________________ Tinyos-help mailing list [email protected] https://mail.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help _______________________________________________ Tinyos-help mailing list [email protected] https://mail.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
