Am Samstag, 21. April 2007 20:45 schrieb njh:
> On Sat, 21 Apr 2007, Paul Alfille wrote:
> > The problem isn't technical -- Louis Swart does it (PIC based) in his LCD
> > controller.
> >
> > Dallas/Maxim restricts 1-wire slaves (their patents, intellectual
> > property, and "quality assurance"), while making bus master design freely
> > available and unrestricted. I think it's a poor business decision,
> > limitting their market, mindshare, etc, but they seem to have the right.
>
> I agree, this seems rather stupid (and probably explains the lack of new
> products built around it).
>
To guarantee unique slave adresses, Dallas Semi's choice is just an obvious
one...
> > The DS2408 can also talk to a microprocessor a byte at a time, with a
> > strobe line to coordinate data transfer. We'd have to do some additions
> > to OWFS to support that mode, but it's quite doable.
>
> Yes, my friend is prototyping this approach. But it's ugly, uses up 9
> port pins, requires the PIC to interrupt to handle data (rather than
> reading from shared memory as with the 2404) and requires another layer of
> checksumming. The 2404 based approach was very elegant (although allowing
> bus mastering would make it the ultimate low cost sensor/actuator
> networking interface).
>
Ouch. The DS2404 was a useful chip for such appliances. I planned to use it in
a future design, too. I have a datasheet from last year without "Do not use
for new designs" printed over it...
> I don't suppose dallas/maxim are amenable to listening to us mere
> hobiests...
>
Not being a mere hobbyist, I'll ask at Maxim about the discontinuation of
DS2404... maybe there will be a substitute for this.
Kind regards
Jan
--
Linux, Playboy Edition: nichts als die nackte Kommandozeile...
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