Re: [Tinyos-help] 802.15.4 TinyOS Qs
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
Re: [Tinyos-help] 802.15.4 TinyOS Qs
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
___
Tinyos-help mailing list
Tinyos-help@millennium.berkeley.edu
https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
Re: [Tinyos-help] 802.15.4 TinyOS Qs
On Sep 5, 2008, at 12:56 PM, Eric Decker wrote: > 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. > Well, this is the 802.15.4 specification, so... Phil ___ Tinyos-help mailing list Tinyos-help@millennium.berkeley.edu https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
