of Microprocessors

126 MUSICAL ApPLICATIONS OF MICROPROCESSORS
the user's manual. The reason given for such behavior is that users are not yet
sophisticated enough to handle the increased f1exibility olTered by programmability.
The forces necessary to change this attitude are already at work,
however, because the increasing number of computers in use also brings on
increased public awareness of their nature, and most importantly, programmability.
In the 1960s, computers were so expensive that only large
corporation accounting departments and well-financed research organizations
could afford them. Consequently, there were very few people working with
and knowledgable about computers and programming. Now with inexpensive
business and school computers and particularly millions of home and
hobby computers, many more people are being exposed to programming
concepts. It has been proven many times with elementary school children
that programming itself is an easy skill to acquire, and what's more, is nearly
intoxicating when introduced properly. Thus, a more aware public will
encourage designers of all microprocessor products, not just synthesis
equipment, to make available full f1exibility through programming.
In this chapter, a cursory review of the history of microprocessors will
be given and the important characteristics of three microprocessor chips that
will be exemplified in Sections II and III will be outlined. Unfortunately, a
tutorial overview of microprocessor hardware and software fundamentals
would require an entire book this size to cover. For those unfamiliar with
computers in general, there are indeed several such volumes, at least one of
which should be read in conjunction with the remaining text of this book.
Those only familiar with a high-level computer language such as BASIC or
FORTRAN should also study the sections of those books devoted to machine
code programming. The discussion to follow will therefore assume some
familiarity with fundamental hardware and software concepts so that we may
concentrate on the specifics of music synthesis with microprocessors.
Microprocessor Terminology
The terminology that will be used very frequently in the discussions to
follow needs to be defined. A microprocessor is the central processing unit
(CPU) of a computer system built with a small number of integrated circuits.
Most microprocessors are single ICchips, although the more powerful ones
may be a set of highly specialized ICs specifically designed to work together.
Standard logic components have also been put on a single printed circuit
board and marketed as "microprocessors," but they do not fit the present
definition.
A microcomputer is a microprocessor with program memory, data storage
memory, and input and output means added. It is functionally equivalent to
the contents of conventional minicomputer cabinets. Recently, single-chip
microcomputers have become available. Although they satisfy the definition,