On Tue, 2009-04-07 at 08:59 +0100, Alan B. Pearce wrote:
> >So, one possible outcome is, that after reading all these replies,
> >you may decide that polling ain't so bad after all.  This all is
> >quite an adventure for an i2c first-timer.
> 
> There is an alternative to polling, doing a token passing to determine who 
> is master. It will require each master to know the next address of who may 
> want to be a master in the system, to know who to pass the 'master' token 
> to, but that could be set up by a broadcast message from the 'master 
> master'.

I hadn't thought of token passing, it might be useful if the collision
detection doesn't work well enough....

It will be a totally static system so "next address" can be hard coded
without a problem.   

> This will save the overhead of one device doing all the polling. Each device 
> 'just' needs to look for the message that passes the master token, and if it 
> doesn't require access to other devices, it passes the token on to the next 
> potential master. 

I shall think about this, but right now I have the simpler task of an
RS-232 interface to the host to implement.   

PeterO
 

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