Lecture-1
An Overview of Microprocessor
The first question that comes in one’s mind is "What is a
microprocessor?”. Let us start with a more familiar term computer. A
digital computer is an electronic machine capable of quickly
performing a wide variety of tasks. They can be used to compile,
correlate, sort, merge and store data as well as perform complex
calculations at much faster rate than human being by means of
stored instructions.
A digital computer is different from a general purpose calculator
in a sense that digital computer is capable of operating according to
the instructions that are stored within the computer whereas a
calculator must be given instructions on a step by step basis to
perform calculations. By this definition a programmable calculator can
be considered a computer.
Historically, digital computers have been categorized according
to the size using the words large, medium, minicomputer and
microcomputer. In the early years of development, the emphasis was
on large and more powerful computers. Large and medium sized
computers were designed to solve complex scientific and engineering
problems. In early stage of development these computers were
accessible and affordable only to large corporations, big universities
and government agencies. Later on, minicomputers were made
available for use in office, small collage, medium size business
organization, small factory etc. As the technology has advanced from
SSI to VLSI & SLSI, the face of the computer has changed gradually
, and it became possible to build the entire central processing unit
(CPU) on a single-chip known as microprocessor.
A control processing unit (CPU) with its related timing functions
on a single chip known as microprocessor. A microprocessor
combined with memory and input/output devices forms a
microcomputer.
The microcomputer is making an impact on every activity of
mankind. It is being used in almost all control applications. For
example analytical and scientific instruments, data communication,
character recognition, musical instruments, household items, defence
equipments, medical equipments etc.
Microcomputers or, in general, computers communicate and
operate in binary numbers ‘0’ and ‘1’ also known as bits. A bit is the
abbreviation for the term binary digit. The bit size of a microprocessor
refers to the number of bit which can be processed simultaneously by
the arithmetic circuit of the microprocessor. A number of bits taken as
a group in this manner is called word. For example, the first
commercial microprocessor the Intel 4004 which was introduced in
1971 is a 4-bit machine and is said to process a 4-bit word. A 4-bit
word is commonly known as nibble and an 8-bit word is commonly
known as byte. Intel 8085A is an 8-bit microprocessor whereas Intel
8086 is a 16-bit microprocessor. It should be noted that a processor
can perform calculations involving more than its bit size but through
program and takes more time to complete the operation. For
example, multi-byte data can be added byte by byte in 8085A
processor which is an 8-bit processor. The short word length requires
few circuitry and interconnection in the CPU.
An Overview of Microprocessor
The first question that comes in one’s mind is "What is a
microprocessor?”. Let us start with a more familiar term computer. A
digital computer is an electronic machine capable of quickly
performing a wide variety of tasks. They can be used to compile,
correlate, sort, merge and store data as well as perform complex
calculations at much faster rate than human being by means of
stored instructions.
A digital computer is different from a general purpose calculator
in a sense that digital computer is capable of operating according to
the instructions that are stored within the computer whereas a
calculator must be given instructions on a step by step basis to
perform calculations. By this definition a programmable calculator can
be considered a computer.
Historically, digital computers have been categorized according
to the size using the words large, medium, minicomputer and
microcomputer. In the early years of development, the emphasis was
on large and more powerful computers. Large and medium sized
computers were designed to solve complex scientific and engineering
problems. In early stage of development these computers were
accessible and affordable only to large corporations, big universities
and government agencies. Later on, minicomputers were made
available for use in office, small collage, medium size business
organization, small factory etc. As the technology has advanced from
SSI to VLSI & SLSI, the face of the computer has changed gradually
, and it became possible to build the entire central processing unit
(CPU) on a single-chip known as microprocessor.
A control processing unit (CPU) with its related timing functions
on a single chip known as microprocessor. A microprocessor
combined with memory and input/output devices forms a
microcomputer.
The microcomputer is making an impact on every activity of
mankind. It is being used in almost all control applications. For
example analytical and scientific instruments, data communication,
character recognition, musical instruments, household items, defence
equipments, medical equipments etc.
Microcomputers or, in general, computers communicate and
operate in binary numbers ‘0’ and ‘1’ also known as bits. A bit is the
abbreviation for the term binary digit. The bit size of a microprocessor
refers to the number of bit which can be processed simultaneously by
the arithmetic circuit of the microprocessor. A number of bits taken as
a group in this manner is called word. For example, the first
commercial microprocessor the Intel 4004 which was introduced in
1971 is a 4-bit machine and is said to process a 4-bit word. A 4-bit
word is commonly known as nibble and an 8-bit word is commonly
known as byte. Intel 8085A is an 8-bit microprocessor whereas Intel
8086 is a 16-bit microprocessor. It should be noted that a processor
can perform calculations involving more than its bit size but through
program and takes more time to complete the operation. For
example, multi-byte data can be added byte by byte in 8085A
processor which is an 8-bit processor. The short word length requires
few circuitry and interconnection in the CPU.
