A microcontroller is a
single chip microcomputer made through VLSI fabrication. A microcontroller also
called an embedded controller because the microcontroller and its support
circuits are often built into, or embedded in, the devices they control. A microcontroller
is available in different word lengths like microprocessors
(4bit,8bit,16bit,32bit,64bit and 128-bit microcontrollers are available today).
1) A microcontroller basically contains one or more following components:
ü
Central
processing unit (CPU)
ü
Random
Access Memory (RAM)
ü
Read
Only Memory (ROM)
ü
Input/output
ports
ü
Timers
and Counters
ü
Interrupt
Controls
ü
Analog
to digital converters
ü
Digital
analog converters
ü
Serial
interfacing ports
ü
Oscillatory
circuits
2) A microcontroller internally consists of
all features required for a computing system and functions as a computer
without adding any external digital parts in it.
3) Most of the pins in the microcontroller
chip can be made programmable by the user.
4) A microcontroller has many bits handling
instructions that can be easily understood by the programmer.
5) A microcontroller is capable of handling
Boolean functions.
6) Higher speed and performance.
7) On-chip ROM structure in a microcontroller
provides better firmware security.
8) Easy to design with low cost and small
size.
Difference between
Microprocessor and Microcontroller:
|
Microprocessors |
Microcontrollers |
|
It is used for big applications. |
It is used to execute a single task within
an application. |
|
Microprocessor is the heart of computer
system. |
It is the heart of the embedded system. |
|
It is just a processor. Memory and I/O
components have to be having to be connected externally. |
Microcontroller contains external processor
along with internal memory and I/O components. |
|
Since I/O and memory connected externally,
the circuit becomes large. |
Since I/O and memory present internally,
the circuit is small. |
|
Can't be used in compact systems and hence
inefficient. |
Can be used in compact systems and
microcontroller is an efficient technique. |
|
Cost of entire system increases. |
Cost of entire system is low. |
|
Power consumption is high. |
Power consumption is low. |
|
Most of the microprocessors do not have
power saving modes. |
Most of the microcontrollers have power
saving mode. |
|
Difficult to replace. |
Easy to replace. |
|
Mainly used in personal computers. |
Used mainly in washing machine, MP3
players. |
Advantages
of Microcontrollers
The main advantages of microcontrollers are
given.
a)
Microcontrollers act as a microcomputer without any digital parts.
b) As the higher
integration inside microcontroller reduces cost and size of the system.
c) Usage of a
microcontroller is simple, easy to troubleshoot and system maintaining.
d) Most of the pins
are programmable by the user for performing different functions.
e) Easily
interface additional RAM, ROM, I/O ports.
f) Low
time required for performing operations.
Disadvantages of
Microcontrollers
a)
Microcontrollers have got more complex architecture than that of
microprocessors.
b) Only perform a
limited number of executions simultaneously.
c) Mostly used
in micro-equipments.
d) Cannot interface
high power devices directly.
Applications
You can find microcontrollers in all kinds of
electronic devices these days. Any device that measures, stores, controls,
calculates, or displays information must have a microcontroller chip inside.
The largest single use for microcontrollers is in the automobile industry
(microcontrollers widely used for controlling engines and power controls in
automobiles). You can also find microcontrollers inside keyboards, mouse,
modems, printers, and other peripherals. In test equipment, microcontrollers
make it easy to add features such as the ability to store measurements, to
create and store user routines, and to display messages and waveforms. Consumer
products that use microcontrollers include digital camcorders, optical players,
LCD/LED display units, etc. And these are just a few examples.
Some basic applications of a microcontroller
are given below.
a) Used in
biomedical instruments.
b) Widely used in
communication systems.
c) Used as a
peripheral controller in PC.
d) Used in robotics.
e) Used in
automobile fields.
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