Programmable Logic Devices (PLDs) have become the key implementation
medium for the vast majority of digital circuits designed today. While
the highest-volume devices are still built with full-fabrication rather
than field- programmability, the trend towards ever fewer ASICs and more
FPGAs is clear. This makes the field of PLD architecture ever more
important, as there is stronger demand for faster, smaller, cheaper and
lower-power programmable logic. PLDs are 90% routing and 10% logic. This
book focuses on that 90% that is the programmable routing: the manner in
which the programmable wires are connected and the circuit design of the
programmable switches themselves. Anyone seeking to understand the
design of an FPGA needs to become lit- erate in the complexities of
programmable routing architecture. This book builds on the
state-of-the-art of programmable interconnect by providing new methods
of investigating and measuring interconnect structures, as well as new
programmable switch basic circuits. The early portion of this book
provides an excellent survey of interconnec- tion structures and
circuits as they exist today. Lemieux and Lewis then provide a new way
to design sparse crossbars as they are used in PLDs, and show that the
method works with an empirical validation. This is one of a few routing
architecture works that employ analytical methods to deal with the
routing archi- tecture design. The analysis permits interesting insights
not typically possible with the standard empirical approach.
