A suggestion:
Can someone with write access to the tree add some comments to this effect
to the source code?
eric
On Fri, Sep 5, 2008 at 8:55 AM, David Moss <[EMAIL PROTECTED]> wrote:
> Length = length of the header + payload of the packet, minus the size of
> the length byte itself (1). This is what allows for variable length
> packets.
>
>
>
> DSN = Data Sequence Number, a number incremented for each packet sent by a
> particular node. This is used in acknowledging that packet, and also
> filtering out duplicate packets.
>
>
>
> Type = TinyOS AM type. When you create a new AMSenderC(AM_WHATEVER), the
> AM_WHATEVER definition is the type of packet.
>
>
>
> TOSH_DATA_LENGTH defaults to 28, it represents the maximum size of the
> payload portion of the packet, and is specified in the tos/types/message.h
> file.
>
>
>
> All of these fields will be filled in automatically by the radio stack when
> you attempt to send a message.
>
>
>
> -David
>
>
>
>
>
>
>
>
>
> *From:* [EMAIL PROTECTED] [mailto:
> [EMAIL PROTECTED] *On Behalf Of *Jim Fell
> *Sent:* Friday, September 05, 2008 8:45 AM
> *To:* tinyos-help@millennium.berkeley.edu
> *Cc:* Jim Fell
> *Subject:* [Tinyos-help] 802.15.4 TinyOS Qs
>
>
>
> Hello. On lines 45 through 59 of …/tinyos-2.x/tos/chips/cc2420/CC2420.h
> the CC2420 header is specified:
>
>
>
> typedef nx_struct cc2420_header_t {
>
> nxle_uint8_t length;
>
> nxle_uint16_t fcf; // Frame Control (Field)
>
> nxle_uint8_t dsn;
>
> nxle_uint16_t destpan; // Destination PAN ID
>
> nxle_uint16_t dest; // Destination address
>
> nxle_uint16_t src; // Source address
>
>
>
> /** I-Frame 6LowPAN interoperability byte */
>
> #ifdef CC2420_IFRAME_TYPE
>
> nxle_uint8_t network; // I-frame (interoperability frame) byte
>
> #endif
>
>
>
> nxle_uint8_t type; // Packet type
>
> } cc2420_header_t;
>
>
>
> Can someone please clarify for me what the length and dsn fields are? Is
> dsn Device Sequence Number? How is length used?
>
>
>
> Can the type field be anything? For example, if I wanted to add additional
> RF commands to the stack, could I make my own definitions using this type
> field to specify each, or is it a static field?
>
>
>
> Where is the maximum payload size specified? Is it TOSH_DATA_LENGTH (line
> 96 of CC2420.h)?
>
>
>
> Thanks,
>
>
>
> -Jim
>
>
>
> _______________________________________________
> Tinyos-help mailing list
> Tinyos-help@millennium.berkeley.edu
> 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
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