Re: TI-H: Multimaster I2C routines


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Re: TI-H: Multimaster I2C routines



Josha Foust wrote:
> 
> >
> > Josha Foust wrote:
> >
> > >         One of the biggest problems with networking any number of calculators
> > > with radio links is that no two calculators could transmit on the same
> > > frequency.  The best way would be to have a centralized hub, but thats still
> > > two frequencies per calculator on the network.  I could be wrong about this,
> > > because Im not sure how Cell phones handle it...  I think a network of
> > > calculators is an insane idea anyway!
> >
> > Nope, it's not a very big problem. The I2C protocol was designed for
> > just this purpose, to use only 2 data lines for a network of IC's. And
> > you can use I2C on radio networks, so you need only two frequencies for
> > the whole network. Only one calculator can transmit at a time, but it's
> > not a big problem.
> >
> 
> Actually this is a very big problem.  Even if one could achieve 35kb/s on
> every calculator on the network, your throughput would be 35/number of
> calculators!  So after about 5 calculators you will have very little bandwidth
> to work with.

Well, perhaps we could design something such as this.  Each calc would
listen for information with it's own number, or and identification
number and ignore everything else.  This way only calculators actually
using the network would use up the bandwidth.  Therefore it would really
be 35/2 because only two calcs would be using the network at once
(except for the identification calls) which isn't that big of a problem.

-- 
Andy Johnson





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