PART 2: INTRODUCTION TO
MCS-85™
THE
MCS·SS™
MICROCOMPUTER
SYSTEM
The
basic
philosophy
behind
the
MCS·85
microcomputer system is one of logical, evolu-
tionary
advance in
technology
without
the
waste
of
discarding
existing
investments in
hardware and software. The MCS-85 provides
the existing 8080 user
with
an increase in per-
formance, a decrease in the component count,
operation from a single 5-Volt power supply, and
still
preserves 100% of his existing software in-
vestment. For the' new microcomputer user, the
MCS-85 represents the refinement of the most
popular microcomputer in the industry, the Intel
8080, along with a wealth
of
supporting soft-
ware,
documentation
and
peripheral
com-
ponents
to
speed the cycle from prototype
to
production. The same development tools that
Intel
has
produced
to
support
the
8080
microcomputer system can be used for the
MCS-85, and additional add-on features are
available to optimize system development for
MCS-85~
This section of the MCS-80/85 User's Manual
will briefly detail the basic differences between
the
MCS-85
and MCS-80 families. It will illus-
trate both the hardware and software compati-
bilities and also reveal some
of
the engineering
trade-ofts that were met during the design 'of
the
MCS-85.
More detailed discussion of the
MCS-85
bus
operation
and
component
specifications are available in Chapters:
2,
3,
4,
and
5.
The information provided in Chapter 1
will
be
helpful in understanding the basic con-
cepts and philosophies behind the
MCS-85.
EVOLUTION
In December 1971, Intel introduced the
first
general purpose, 8-bit
microprocessor,
the
8008. It was implemented in P-channel MOS
technology and was packaged in a single
18
pin, dual in-line package
(DIP).
The 8008 used
standard semiconductor
ROM
and
RAM
and,
for the most part, TTL components for I/O and
general interface. It immediately found applica-
tions
in byte-oriented end products such as ter-
minals and computer peripherals where
its
in-
struction execution
(20
micro·seconds), general
1·6
60
30
15
3
1
1\
\ 8080
~
~
80SOA
"-
8080A
AND
PERIPHERALS
\ 8085
1971 1972 1973 1974 1975 1976 1977
8-BIT SMALL
SYSTEM
COMPONENT
COUNT
1971
-1977