What is the relationship between a Tinyos message_t type message, particularly CC2420 message, and 802.15.4 MAC Layer frame? (TinyOS 802.15.4 Frames specification can be found here<http://www.tinyos.net/tinyos-2.x/doc/html/tep125.html> .)
As for 802.15.4 Standard, nxle_uint8_t length is PHR. So the MAC Layer header is 11bytes(including nxle_uint8_t network and type) Could you please give me some reference on why this is true? The maxium MAC Layer frame is 127bytes. Where can I find this? I notice it is said to be 128 bytes in one of the archived email<https://www.millennium.berkeley.edu/pipermail/tinyos-help/2007-July/026346.html> s. Thanks for your patience. -Xiaohui On Sat, May 9, 2009 at 8:01 AM, Lizhao You <[email protected]> wrote: > I think the maxium TOSH_DATA_LENGTH should be 114bytes(including 114). > > For Telosb, the header_t definition: > platfom_message.h > typedef union message_header { > cc2420_header_t cc2420; > serial_header_t serial; > } message_header_t; > > CC2420.h > typedef nx_struct cc2420_header_t { > nxle_uint8_t length; > nxle_uint16_t fcf; > nxle_uint8_t dsn; > nxle_uint16_t destpan; > nxle_uint16_t dest; > nxle_uint16_t src; > > /** I-Frame 6LowPAN interoperability byte */ > #ifdef CC2420_IFRAME_TYPE > nxle_uint8_t network; > #endif > > #ifndef TINYOS_IP > nxle_uint8_t type; > #endif > > } cc2420_header_t; > > cc2420_header_t is 12byte. As for 802.15.4 Standard, nxle_uint8_t length is > PHR. So the MAC Layer header is 11bytes(including nxle_uint8_t network and > type) , then FCS is 2bytes. The maxium MAC Layer frame is 127bytes. So > TOSH_DATA_LENGTH should not exceed 127-11-2=114byte. > > I had tested the maxium TOSH_DATA_LENGTH, and remembered that it is > 114bytes, although in Makefile we can set TOSH_DATA_LENGTH more than 114. I > run BlinkToRadio and changed BlinkToRadio.h payload, then run BaseStation to > see whether it works. > > Regards, > Lizhao > > 2009/5/9 Eric Decker <[email protected]> > > The maximum that TOSH_DATA_LENGTH can be set do is determined by the CC2420 >> h/w. >> >> eric >> >> >> On Fri, May 8, 2009 at 9:09 PM, Xiaohui Liu <[email protected]> wrote: >> >>> Hi Eric, >>> >>> Thanks for your help. The same is found in >>> TOSROOT\tos\chips\cc2420\CC2420.h. >>> However, neither of them talks about the max value that can be set. Any >>> thought? >>> -Xiaohui >>> >>> On Fri, May 8, 2009 at 11:32 PM, Eric Decker <[email protected]> wrote: >>> >>>> You have to start the search from the top level of the T2 tree. >>>> >>>> I get the following as well as others: >>>> >>>> ./tos/types/message.h:6:#ifndef TOSH_DATA_LENGTH >>>> ./tos/types/message.h:7:#define TOSH_DATA_LENGTH 28 >>>> >>>> >>>> eric >>>> >>>> >>>> >>>> On Fri, May 8, 2009 at 8:07 PM, Xiaohui Liu <[email protected]> wrote: >>>> >>>>> I appreciate your help and I find TOSH_DATA_LENGTH in >>>>> TOSROOT\tos\chips\cc2420\CC2420.h, >>>>> but it contains no info on the maximum of TOSH_DATA_LENGTH. Any other >>>>> idea? Thanks. >>>>> -Xiaohui >>>>> >>>>> On Fri, May 8, 2009 at 7:05 PM, Eric Decker <[email protected]> wrote: >>>>> >>>>>> The best way is to look in the source code. >>>>>> I use something like >>>>>> >>>>>> find . -exec grep -nHi tosh_data_length \{\} \; >>>>>> >>>>>> >>>>>> >>>>>> On Fri, May 8, 2009 at 3:42 PM, Xiaohui Liu <[email protected]> wrote: >>>>>> >>>>>>> Hi all, >>>>>>> What is the max value of TOSH_DATA_LENGTH I can set in TinyOS 2.x? I >>>>>>> find some previous discussions on this, but it seems to me no >>>>>>> conclusion has >>>>>>> been reached. Also do I find it in TEP 111, which does not clarify this >>>>>>> neither. Thanks for your availability. >>>>>>> >>>>>>> -Xiaohui >>>>>>> >>>>>>> _______________________________________________ >>>>>>> Tinyos-help mailing list >>>>>>> [email protected] >>>>>>> >>>>>>> https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help >>>>>>> >>>>>> >>>>>> >>>>>> >>>>>> -- >>>>>> Eric B. Decker >>>>>> Senior (over 50 :-) Researcher >>>>>> Autonomous Systems Lab >>>>>> Jack Baskin School of Engineering >>>>>> UCSC >>>>>> >>>>>> >>>>> >>>> >>>> >>>> -- >>>> Eric B. Decker >>>> Senior (over 50 :-) Researcher >>>> Autonomous Systems Lab >>>> Jack Baskin School of Engineering >>>> UCSC >>>> >>>> >>> >> >> >> -- >> Eric B. Decker >> Senior (over 50 :-) Researcher >> Autonomous Systems Lab >> Jack Baskin School of Engineering >> UCSC >> >> >> _______________________________________________ >> Tinyos-help mailing list >> [email protected] >> https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help >> > > > > -- > Lizhao You > Undergraduate Student of GPS Group > Department of Computer Science and Technology, Nanjing University > Nanjing, Jiangsu, 210093 China PR. >
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