> On Wed, 9 Sep 1998, Richard B. Johnson wrote:
>
> > On Wed, 9 Sep 1998, Daniel Engstrom wrote:
> >
> > > On 8 Sep, David Lang wrote:
> > >
[SNIPPED]
> >
> > Therefore, everybody on the bus has to use a pseudo-random back-off-time to
> > resolve deadlocks.
>
> Eh? Are we talking about $I^{2}C$? It sounds like you are talking about
> Ethernet. I could have sworn that I remembered I2C being a clocked
> tri-state bus (or whatever the correct terminology is), with automatic
> backoff (multiple devices can start transmitting at once: the first one to
> notice the bus differing from what it is sending simply stops
> transmitting.
You can write and read at the same time. You don't know that somebody
else is attempting to write while you are.
The bus is unharmed by this, and one message is guaranteed
> to go though.
The bus is permanently hung until both persons who thought they were
the master, reinitialize their controllers.
No messages are guaranteed to go through.
The devices that backed off start again after the mssage is
> complete, just as David Lang was describing). There is no exponential
> backoff, no bus crashing, no deadlocks, etc. I always thought it was an
> quite elegant bus, to be honest.
>
It is just a cheap interface bus designed to communicate with something
that didn't require reliable communication and I can't imagine what
that would be. Even TV-Tuners need to be set to the correct channel.
Cheers,
Dick Johnson
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