[Tinyos-devel] Parameterization of UartStream interface in UART abstraction on all platforms?

[Kevin Klues]

So I started looking at the Atm128Uart stuff and noticed that it is
not enabled for Resource arbitration at all.  The changes to the
Msp430Uart components were rather straight forward since an arbiter
was already used to arbitrate across the UartByte interrace, and all
that was needed for UartStream was to parameterize it and wire in the
correct client id in order to enforce arbitration.

It would be somewhat straightforward to introduce Resource arbitration
to the Atm128Uart component, but this raises issues for the users of
this component since they are implemented with the assumption that
there is no arbitration and for that matter currently don't wire in a
Resource interface to take control of the uart.  The primary place
where I noticed this will cause issues is in the PlatformSerialC for
any atm128x based platforms.  In order to operate they will
(minimally) need to now have a PlatfromSerialP component (similar to
how telos does it) and perform an immediateRequest on the Resource.

My question is whether it is worth it to make these changes now or
wait until after the release.  The changes would require testing on
all atm128x platforms and changing the semantics of any components in
tinyos that use the Atm128Uart0C component.

Kevin

On Thu, May 15, 2008 at 7:56 AM, Vlado Handziski
<handzisk at tkn.tu-berlin.de> wrote:
> As discussed in the thread here started by Eric Decker, parametrization of
> the UartStream interfaces exported from the UART abstraction can simplify
> the event handling logic in the user components. Eric has sent patches to
> this end for the msp430 which Kevin will test and incorporate in the tree,
> as agreed at the teleconference yesterday.
>
> I am not sure who is currently maintaining the UART components for the
> atm128 but the current implementation does not support multiple users
> through arbitration. Although this is not currently needed, we never know
> when a platform might come that needs this functionality, as in Eric's case
> for the msp430. In principle all HIL level abstractions should by default
> support arbitrated operation, and buses in particular. So maybe this is a
> good opportunity to line up the abstractions on the different
> microcontrollers?
>
> Vlado
>
>
>
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-- 
~Kevin