vi EMBE DDED SYSTEM DESIGN:
tems have been manufactured for years, industry and academia have not been
sufficiently focused on developing and formalizing a system-level design tech-
nology and methodology, even though there was a clear need for it. This need
has been magnified by appearance of embedded systems, which can be used
anywhere and everywhere, in plains, trains, houses, humans, environment, and
manufacturing and in any possible infrastructure. They are application specific
and tightly constrained by different requirements emanating from the environ-
ment they operate in. Together w ith ever increasing complexities and market
pressures, this makes their design a tremendous challenge and the development
of a clear and well-defined system-level design technology unavoidable.
There are two reasons for emphasizing more abstract, system-level method-
ologies. T he first is the fact that high-level abstractions are closer to a designer’s
usual way of reasoning. It would be difficult to imagine, for example, how a
designer could specify, model and communicate a system design by means of
a schematic or hundred thousand lines of VHDL or Verilog code. The more
complex the design, the more difficult it is for the designer to comprehend its
functionality when it is specified on register-transfer level of abstraction. On
the other hand, when a system is described with an application-oriented model
of computation as a set of processes that operate on abstract data types and
communicate results through abstract channels, the designer will find it much
easier to specify and verify proper functionality and to evaluate various imple-
mentations using different technologies. The second reason is that embedded
system are usually defined by the experts in application domain who understand
application very well, but have only basic knowledge of design technology and
practice. System-level design technology allows them to specify, explore and
verify their embedded system products without expert knowledge of system
engineering and manufacturing.
It must be acknowledged that research on system design did start many years
ago; at the time, however, it remained rather focused to specific domains and
communities. For example, the computer architecture community has consid-
ered ways of partitioning and mapping computations to different architectures,
such as hypercubes, multiprocessors, massively parallel or heterogeneous pro-
cessors. The software engineering community has been developing methods
for specifying and generating software code. The CAD community has focused
on system issues such as specification capture, languages, and modeling. How-
ever, simulation languages and models are not synthesizable or verifiable for
lack of proper design meaning and formalism. That resulted in proliferation
of models and modeling styles that are not useful beyond the modeler’s team.
By introduction of well-defined model semantics, and corresponding model
transformations for different design decision, it is possible to generate models
automatically. Such models are also synthesizable and verifiable. Furthermore,
model automation relieves designers from error-prone model coding and even
