Title of Paper : EVOLUTION OF MICROPROCESSORS
Grade Received on Report : 79%

Only once in a lifetime will a new invention come about to touch every aspect of our lives. Such a device
that changes the way we work, live, and play is a special one, indeed. The Microprocessor has been around
since 1971 years, but in the last few years it has changed the American calculators to video games and
computers (Givone 1). Many microprocessors have been manufactured for all sorts of products; some have
succeeded and some have not. This paper will discuss the evolution and history of the most prominent 16
and 32 bit microprocessors in the microcomputer and how they are similar to and different from each other.
Because microprocessors are a subject that most people cannot relate to and do not know much about, this
paragraph will introduce some of the terms that will be involved in the subsequent paragraphs. Throughout
the paper the 16-bit and 32-bit microprocessors are compared and contrasted. The number 16 in the 16-bit
micro-processor refers how many registers there are or how much storage is available for the
microprocessor (Aumiaux, 3). The microprocessor has a memory address such as A16, and at this address
the specific commands to the microprocessor are stored in the memory of the computer (Aumiaux, 3). So
with the 16-bit microprocessor there are 576 places to store data. With the 32-bit microprocessor there are
twice as many places to store data making the microprocessor faster.
Another common term which is mentioned frequently in the paper is the os-cillator or the time at which the
processors “clock” ticks. The oscillator is the pace maker for the microprocessor which tells what
frequency the microprocessor can process information, this value is measured in Mega-hertz or MHz. A
nanosecond is a measurement of time in a processor, or a billionth of a second. This is used to measure the
time it takes for the computer to execute an instructions, other wise knows as a cycle.
There are many different types of companies of which all have their own family of processors.
Since the individual processors in the families were developed over a fairly long period of time, it is hard to
distinguish which processors were in-troduced in order. This paper will mention the families of processors
in no particular order. The first microprocessor that will be discussed is the family of microproces-sors
called the 9900 series manufactured by Texas Instruments during the mid-70s and was developed from the
architecture of the 900 minicomputer series (Titus, 178). There were five different actual microprocessors
that were designed in this family, they were the TMS9900, TMS9980A, TMS9981, TMS9985, and the
TMS9940. The TMS9900 was the first of these microprocessors so the next four of the microprocessors
where simply variations of the TMS9900 (Titus, 178). The 9900 series microprocessors runs with 64K
memory and besides the fact that the 9900 is a 16-bit micropr!
ocessor, only 15 of the address memory circuits are in use (Titus, 179). The 16th address is used for the
computer to distinguish between word and data functions (Titus, 179. The 9900 series microprocessors
runs from 300 nanoseconds to 500 ns from 2MHz to 3.3MHz and even some variations of the original
microprocessor where made to go up to 4MHz (Avtar, 115).
The next microprocessor that will be discussed is the LSI-11 which was pro-duced from the
structural plans of the PDP-11 minicomputer family. There are three microprocessors in the LSI-11 family
they are the LSI-11, LSI-11/2, and the much improved over the others is the LSI-11/32 (Titus, 131). The
big difference between the LSI-11 family of microprocessors and other similar microprocessors of its kind
is they have the instruction codes of a microcomputer but since the LSI-11 microproc-essor originated from
the PDP-11 family it is a multi-microprocessor (Avtar, 207). The fact that the LSI-11 microprocessor is a
multi-microprocessor means that many other microprocessors are used in conjunction with the LSI-11 to
function properly (Avtar, 207). The LSI-11 microprocessor has a direct processing speed of 16-bit word
and 7-bit data, however the improved LSI-11/22 can directly process 64-bit data (Titus, 131). The average
time that the LSI-11 and LSI-11/2 process at are 380 nan!
oseconds, while the LSI-11/23 is clocked at 300 nanoseconds (Titus, 132). There are some great