[Tinyos Core WG] arbiter issues

[Philip Levis]

On Oct 23, 2006, at 11:55 AM, Joe Polastre wrote:

> This then implies that all chips with radios must support 32kHz
> precision to be TinyOS 2.x-compliant.  What is the width of the
> timestamp?  32-bits?  16-bits is only a 2 second duration, so that
> implies that the radio stack will not delay the timestamp by more than
> 2 seconds when dispatching to higher layers

Yes.


> , something that may or may
> not be possible based on platform, tasks, etc.

Are you serious?

>
> Timestamping on receive is only half the battle; it is the
> reconciliation of transmit and receive stamps that reconcile timing
> differences between nodes.  Are you suggesting that T2 not initially
> support this in a single packet reception but rather require multiple
> packet transmissions to establish a common time base?
>

Agreed. The point is that these are values which stacks already  
collect and so should be made available. This is different than  
providing a meaningful full time synchronization service, which I  
think would be inadvisable to require stacks to do. It would be  
exactly the kind of thing that an additional interface would provide.

Phil