DESIGN OF A CUSTOM ASIC INCORPORATING CAN™ AND 1 ...

2.5 Network Types and Precedents
As the use and popularity of 1 – Wire® devices has increased over the past two decades,
so to have the methods to extend the 1 – Wire® protocol to networked applications well beyond
the size of a circuit board. There have been many application notes, tech briefs, and other
documents published over the years from a variety of sources, authorized and unauthorized alike,
regarding 1 – Wire® implementations. As the world of 1 – Wire® devices and systems has
grown and evolved, some of the information in these documents has been augmented, modified,
or sometimes even proven incorrect. This has lead to the creation of some misinformation before
a complete analysis of large 1 – Wire® networks was completed, and some was perhaps based
on anecdotal information. As the scope of 1 – Wire® networks has grown, much has been
learned about those characteristics that make a large network reliable, and the devices themselves
have undergone a process of evolution that continues in earnest today.
As is the case with most other communication protocols and buses, a proper match
among network components (i.e., master, network cabling, and 1 – Wire® slave devices) is the
precondition for reliable 1 – Wire® operation. When bus masters are improperly designed or
implemented, or when masters intended for short-line use are pressed into service with greatly
extended communication lines, then satisfactory performance cannot always be expected [4].
Since 1 – Wire® networks are often quite “free form” in structure, this leads to numerous
combinations of wire types and topologies that can be used with 1 – Wire® devices. Due to
space limitations here, only the most general and typical applications associated with 1 – Wire®
networks are considered.
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