2. Microprocessors
• A microprocessor is the brain, the soul as well as the
heart a computer system.
• It includes all the logical functions, data storage, timing
functions and interaction with other peripheral devices.
• The term microprocessor is used interchangeably with the
term Central Processing Unit (CPU).
• The CPU coordinates all functions of a computer.
• It incorporates the functions of a computer’s CPU on a
single integrated circuit or at most a few integrated
circuits.
• It is a multipurpose, programmable device that accepts
digital data as input, processes it according to instructions
stored in its memory and provides results as output.
3. Microprocessors cont’d …
• It generates timing signals, sends and receives data to and
from every peripheral used inside and/or outside the computer.
• The commands required to do this are fed into the device in
form of current variations which are converted into meaningful
instructions by use of Boolean logic system.
• Functions are divided into two categories:- logical and
processing functions
- The ALU and the Control Unit handle these functions
respectively.
• Information is communicated through a bunch of wires called
buses;
- the address bus carries the address of the location with which
communication is desired
- the data bus carries the data that is being exchanged.
4. Microprocessors cont’d …
A processor may be referred to as a circuitry that
responds to and processes basic instructions that drive a
computer.
CPU – hardware in a computer that helps execute a
program(s)
When such a processor is in a PC / Desktop or is
embedded in a small device(s), it is referred to as a
microprocessor.
Examples:
• Intel – Pentium family (I, II, III, IV), Itanium family (i3, i5, i7)
• AMD – FX family, A series
• ARM
5. Microprocessors cont’d …
• They are designed for specific purpose; graphics processing,
application specific instruction set, application specific for
particular use case, digital signals, image processor,
smartphones
Instruction Set Architecture
• Boundary between software and hardware.
• Is described using five (5) categories;
(i) Operand storage
(ii) Number of operands in an instruction
(iii) Operations
(iv) Operation location – memory or registers
(v) Type and size of operands
6. Applications
• Thousands of items nowadays include microprocessors;
including large and small household appliances, cars, related
accessories, tools and test instruments, toys, light switches /
dimmers, circuit breakers, smoke detectors / alarms, hi-fi audio
/ visual components, cellular phones, HDTV – Explora (DSTV),
PVR
Processor Categories
• Complex Instruction Set Computer (CISC), which offers many
specialized instructions, some of which may only be rarely
used in practical programs.
• Reduced Instruction Set Computer (RISC), which simplifies the
processor by only implementing instructions that are frequently
used in programs; unusual operations are implemented as
subroutines where extra processor execution time is offset by
their rare use.
• Very Long Instruction Word (VLIW), where the processor
receives many instructions encoded and retrieved in one
instruction word.
