[Tinyos-help] Precise contents and length of the 802.15.4 frames (and most especially with the TestNetwork App)

[Philip Levis]

On Jul 3, 2007, at 2:10 PM, John Griessen wrote:

> Steve McKown wrote:
>> 3 - If it's not.. what use does it have?
>>
>
> The metadata is useful for writing network functionality.  It's  
> used in CTP for example, to manage neighbors and routing.  I don't  
> think you'd want an application to use metadata directly, since  
> you're then tying that application to a specific bit of radio  
> hardware.
>
>
> So timestamp metadata should go in a component or an interface?
>
> Has anyone found the most accurate way to deterministically
> clock the arrival of a timing packet, that can be recognized  
> without decoding,
> since its data content never varies?   (The application I have in
> mind is precise timestamping.)   Is there any physical output of  
> the radio for the
> timing of a received packet as the radio locks onto its data  
> transitions, or
> is packet timing and recognizing  all internal and a RX ready   
> interrupt is the earliest
> output?

Take a look at the RadioTimeStamping interface. Some radio stacks  
issue an event on the first data bit of a packet, right after the  
preamble.

Phil