[etherlab-dev] Slave to Slave communication

Florian Pose fp at igh-essen.com
Wed Jan 30 15:45:57 CET 2008

Hallo again,

On Tue, Jan 29, 2008 at 02:16:45PM +0100, Thomas Elste wrote:
> Is there a way, and if not, what would be the best approach to
> allow the users the configuration of a direct _slave to slave_
> communication? In some bus setups with complex- and some I/O-slaves
> this would allow even faster communication between slaves and save
> a great deal of bandwith. For example if the inputs are aligned at
> the start of the bus followed by complex slaves which do some
> calculations, the complex slaves could read in the same bus cycle
> data at the same logical address the inputs have just written
> it on. Likewise for the outputs.
> Such setups aren't often in need of a heavy master PC either. One
> could use a cheap, power saving embedded board (not even necessarily
> x86 based, as shown in my previous mails) as hardware for the master.

Slave-to-slave communication is specified in EtherCAT, but we had no
needs for it, yet. This is the reason, that it's not implemented. ;-)
Moreover, I have not engaged in this, and don't know, what is necessary
to make slaves communicate with each other... Do you have more
background information than I do?

> Ok, that's it for now. Please forgive me this "list-bombing", :).

There's nothing to forgive, separating the different questions into
separate threads was the best thing to do!

Best regards,
Florian Pose


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