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The following archive was created by hippie-mail 7.98617-22 on Fri Aug 21 1998 - 17:16:24 ADT
Brian C. Lane (nexus@tatoosh.com)
Mon, 30 Mar 1998 19:55:56 -0800
Ben Laurie wrote:
> Although I haven't played with a Java iButton yet, I've been messing
> with other members of the family (hmmm ... sounds dodgy :-), and the
> reader can probably be made even cheaper than that - essentially it is
> some rather weird front-end for a serial port that you abuse to do
> 1-wire LAN (for that is the iButton inteface). You drive the serial at
> strange speeds, and read the bytes you write (which come back subtly
> altered) to do the actual comms. Strange but fun stuff.
4 diodes and a resistor. You set the serial port to 115kbps and one byte is
the equivelant of one bit to the one-wire bus. To reset it you use 9600 bps. I
haven't had a chance to play with the iButtons yet (one of my future projects
is a iButton based login for Linux), but I've built a bunch of these adapters
and used them with the Dallas DS1820 digital temperature sensor. See my
webpage for links to all the one-wire protocol .pdf files you need.
Brian
-- ====================================================================== Nexus Computing http://www.eskimo.com/~nexus Electronics, Embedded Software and Linux nexus@tatoosh.com
The following archive was created by hippie-mail 7.98617-22 on Fri Aug 21 1998 - 17:16:24 ADT