[Tinyos-help] CC2420: length field in 802.15.4 header is used without initialisation, fcf field not set in any case

Silvan Nellen Nellen at cmc.ca
Mon Nov 8 06:01:35 PST 2010

Hi Stephen

Yes, the problems are fixed in revision 5215.

Thank you!


-----Original Message-----
From: sdhags at gmail.com [mailto:sdhags at gmail.com] On Behalf Of Stephen Dawson-Haggerty
Sent: November 6, 2010 1:41 AM
To: Silvan Nellen
Cc: tinyos-help at millennium.berkeley.edu
Subject: Re: [Tinyos-help] CC2420: length field in 802.15.4 header is used without initialisation, fcf field not set in any case

Yes, you are correct.  Thanks for suggesting the changes -- can you
check out 5215 and verify that this fixes the problem?


On Thu, Nov 4, 2010 at 9:34 PM, Silvan Nellen <Nellen at cmc.ca> wrote:
> Hello,
> I have two issues regarding revision 5214 (the newest at the time of
> writing) of the trunk (https://tinyos-main.googlecode.com/svn/trunk):
> 1.
> After updating from revision 5160 to 5214, Zigbee communication stopped
> working on Shimmer. Using a Zigbee packet sniffer I found out that all
> updated nodes send packets with the length field of the header set to an
> invalid value. After looking at the source code of the CC2420 driver
> (Shimmer uses CC2420) I found the reason why: the code that sets the length
> field in the header had been commented out
> (/trunk/tos/chips/cc2420/csma/CC2420CsmaP.nc, line 136)! The change was
> introduced in r5174.
> Am I missing something or is this a serious bug that needs to be fixed ?
> 2.
> Another CC2420 related issue is that the fcf field in the header is not set
> in some cases. In the current version of the trunk the fcf field is set in
> the RadioResource.granted() event handler in
> /trunk/tos/chips/cc2420/csma/CC2420ActiveMessageP.nc. However this event is
> not triggered if access to the radio is granted immediately (line 104), in
> this case fcf remains uninitialized!
> Why was the initialization fcf code moved from the Send.send() command in
> tos/chips/cc2420/csma/CC2420CsmaP.nc to RadioResource.granted() ? What would
> be the cleanest way to fix this ? Move the initialization code back to
> CC2420CsmaP.nc?
> Regards,
>  Silvan Nellen
> _______________________________________________
> Tinyos-help mailing list
> Tinyos-help at millennium.berkeley.edu
> https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help

stephen dawson-haggerty
uc berkeley wireless and embedded systems lab
berkeley, ca 94720

More information about the Tinyos-help mailing list