[Tinyos Core WG] Re: [Tinyos-devel] Re: I2C and SPI sharing

[Vlado Handziski]

On 10/27/06, David Gay <dgay42 at gmail.com> wrote:
>
> My motivation for unconfigure was powering off a sensor: the basic
> sensor board sensors don't have a separate arbiter, instead they
> piggyback on the ADC's arbiter and rely on configure/unconfigure to
> power the sensor on and off. If you don't have unconfigure, you can't
> do this. I.e., what you're proposing (relying on other configure
> calls) only works if all clients of the arbiter are controlling the
> exact same set of resources (and that you're using a power manager to
> switch the thing off).
>
>
You are right. The proposed approach will not work for "tunneled"
arbitration. Having the unconfigure here helps, but its semantics can become
confusing in more complicated cases where there is n:1 mapping instead 1:1.

Vlado
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