[ag-automation] application layer use cases for fieldbus stack

[Robert Schwebel]

On Wed, Jul 11, 2007 at 01:26:55PM +0200, Peter Soetens wrote:
> This is a 'dream' I have heard before when developing frameworks for
> embedded.  If you standardise on the API, different libs can fill it
> in and offer single-thread/multi-thread solutions.

I'm not sure if it is possible - we'll see.

> :-) Actually, our components do have a CAN interface using Peak CAN
> and CANPie as backends, and there's where my limited fieldbus
> experience come from.

Ok; note that Peak does in the mean time also use Socket-CAN - it's a
good opportunity to drive things into a mainline direction.

> We are definately overdoing it with respect to super embedded nodes,
> but once in a multi-threaded environment, the advantages become
> apparant.

Yup.

> > Doesn't sound good; think of situations like the netX, where we have 32
> > kB SRAM buffers in the CPU, probably mappable as 8 buffers containing a
> > 4k page; I'd like to be able to use them as TPU buffer space. There is
> > not much space for complete-process-image copies if you have only 8
> > buffers :-)
> 
> I'm sure you're not multithreading in that case and can leave the whole 
> locking or RCU stuff behind.

I'm not sure. netX is a normal 200 MHz ARM environment, and we have it
running with EABI and NPTL. Not too different from any other embedded
CPU, so there's no reason for example not to run a visualization task,
rendering to the onboard video controller on the same box as the
fieldbus stack ...

Robert 
-- 
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