Page 56 - The Mechatronics Handbook

4

Microprocessor-Based

Controllers and

Microelectronics

4.1 Introduction to Microelectronics
4.2 Digital Logic
Ondrej Novak 4.3 Overview of Control Computers
Technical University Liberec
4.4 Microprocessors and Microcontrollers
Ivan Dolezal 4.5 Programmable Logic Controllers
Technical University Liberec 4.6 Digital Communications

4.1 Introduction to Microelectronics

The field of microelectronics has changed dramatically during the last two decades and digital technology
has governed most of the application fields in electronics. The design of digital systems is supported by
thousands of different integrated circuits supplied by many manufacturers across the world. This makes
both the design and the production of electronic products much easier and cost effective. The permanent
growth of integrated circuit speed, scale of integration, and reduction of costs have resulted in digital
circuits being used instead of classical analog solutions of controllers, filters, and (de)modulators.
The growth in computational power can be demonstrated with the following example. One single-
chip microcontroller has the computational power equal to that of one 1992 vintage computer notebook.
This single-chip microcontroller has the computational power equal to four 1981 vintage IBM personal
computers, or to two 1972 vintage IBM 370 mainframe computers.
Digital integrated circuits are designed to be universal and are produced in large numbers. Modern
integrated circuits have many upgraded features from earlier designs, which allow for “user-friendlier”
access and control. As the parameters of Integrated circuits (ICs) influence not only the individually
designed IC, but all the circuits that must cooperate with it, a roadmap of the future development of IC
technology is updated every year. From this roadmap we can estimate future parameters of the ICs, and
adapt our designs to future demands. The relative growth of the number of integrated transistors on a
chip is relatively stable. In the case of memory elements, it is equal to approximately 1.5 times the current
amount. In the case of other digital ICs, it is equal to approximately 1.35 times the current amount.
In digital electronics, we use quantities called logical values instead of the analog quantities of voltage
and current. Logical variables usually correspond to the voltage of the signal, but they have only two
values: log.1 and log.0. If a digital circuit processes a logical variable, a correct value is recognized because
between the logical value voltages there is a gap (see Fig. 4.1). We can arbitrarily improve the resolution
of signals by simply using more bits.

©2002 CRC Press LLC