[Tinyos-devel] SimpleArbiterP bug

[Kevin Klues]

In retrospect, it might have made sense to push this policy outside
the arbiter, and force the mux/demux to occur at some layer above.
Changing the existing code to follow this policy and then providing a
component above that provides the proper multiplexing would be
trivial.  Its just a question of how much code would need to be
changed based on this change.  Are there places other than the tda5250
driver that rely on ResourceRequested?

Kevin

On Wed, Oct 15, 2008 at 5:34 PM, Philip Levis <pal at cs.stanford.edu> wrote:
>
> On Oct 15, 2008, at 5:28 PM, Kevin Klues wrote:
>
>> The idea was first brought in for implementing the priority scheme
>> used to arbitrate access to USART0 between the Tda5250 radio driver
>> and the flash chip on the eyes platform.  I don't remember the
>> details, and Vlado will have to comment, but I think the
>> ResourceRequested interface was used to allow the radio to keep
>> control of the USART while listening for incoming packets, but
>> optionally allow the flash chip to take control if it had things it
>> needed to write quickly.  Making the radio driver the dfault owner
>> complicated things because there were times when a normal power
>> manager would be used to shutdown the USART if neither the radio or
>> the flash needed access to it.
>
> Right -- so the answer here is that you need to mux/demux between multiple
> default owners. When the radio is on, it's the default owner. When it's off,
> the power manager is. This mux/demux can be done outside the arbiter.
>
> Phil
>



-- 
~Kevin