Microcontroller Architecture and
programming
M. Sc 3rd semester
ELE-19305DCE
Er. Abida Yousuf
PG Department of Electronics& Instrumentation
Technology,
University of Kashmir
E-mail:-134ece@gmail.com
overview
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Basic computer system
Introduction to microprocessor and microcontroller
Brief evolution of microcontroller
Criteria for choosing a controller
Need of a microcontroller
Features of microprocessor and microcontroller
Microprocessor VS microcontroller
Basic computer system
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A basic computer system combines Processor, RAM, ROM, I/O
to form the basic hardware of the computer system
contd…
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Microprocessor:-CPU on a single integrated chip (IC), is a
small processor, where small refers to size and not
computational capability. For example intel,pentium and
power pc are microprocessors.
Microcomputer:- A microcomputer is a small computer, where
again small refers to size not computational capability. For
example Desktop pc is a microcomputer
Microcontroller:-Computer on a Chip, i.e contains all the
components of a computer like RAM, ROM I/O, Timers, Serial
ports on a single chip or IC.
Microprocessor
Evolution of microcontroller
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In the year 1976, Motorola created a microprocessor chip
called 6801 which replaced 6800 with certain add on chips to
make a computer this paved the way for the new revolution in
the history of the chip design and give birth to new entity
called microcontroller.
The intel bagged the credit of producing the first
microcontroller 8048 with a CPU and 1K bytes of EPROM ,64
bytes of RAM ,an 8 bit timer and 27 I/O pins in 1976.
Then followed the most popular controller 8051 in the year
1980 with 4K bytes of ROM ,128 Bytes of RAM, a serial port,
two 16 bit timers, and 32 I/O pins.
Contd…
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The same INTEL introduced a 16 bit controller 8096 in year
1982.
Later intel introduced 80c196 series of 16 –bit microcontrollers
for many industrial applications
Microchip, another company has introduced a microcontroller
PIC 16C64 an 8 –bit in the year 1985.
32-bit microcontroller have been developed by IBM And
motorola –MPC 505 is a 32 bit RISC controller of motorola.
The 405 GA is a 32 –bit RISC embedded controller of IBM
In recent times ARM (Advanced RISC machines )has developed
and introduced 32 bit controllers which are highend
application devices,especially communication devices.
Microcontroller
Microcontroller and embedded system
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Microcontroller may be considered as a Specialized computer
on a chip or a single chip computer .The word micro means
device is small and controller means device may be used to
control one or more functions of objects, processes or events.
It is also called as embedded controller as it is always
embedded in the device or the system that it controls.
The word embedded means “hidden inside so one cannot
see it” the software that controls how the program is fixed
inside ROM and is not accessible to the user of the device.
The first microcontroller was developed in 1971 by Texas
Instruments and is called TMS 1000. It was made available for
commercial use in 1974.
Important four characteristics of embedded system
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Typically embedded systems perform single function.
They are tightly constrainted.
Many embedded systems must operate in real time.
Small memory requirements.
Common Microcontrollers
ATMEL
ARM
8 BIT E.G MCS48,MCS51, 8XC42 ,8XC251
INTEL
National Semiconductor
Microchip
16 BIT E.G MCS96,MXCS296
14 BIT PIC E.G PIC16F84
16 BIT PIC
Texas Instruments
E.G MSP 430, TMS 370
Zilog E.G Z8,Z86E02
8 bit E.G 68HC05,68HC08
Motorola
16 bit E.G 68HC12, 68HC17
Microcontroller classification
Criteria for choosing a microcontroller
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Meeting the computing needs of the task efficiently and
cost effectively
 speed, the amount of ROM and RAM, the number of I/O
ports and timers, size, packaging, power consumption
 easy to upgrade
 cost per unit
Availability of software development tools
 assemblers, debuggers, C compilers, emulator, simulator,
technical support
Wide availability and reliable sources of the
microcontrollers.
Typical features of microprocessor and microcontroller
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Smaller size
Cost reduction
Higher reliability
Lower power consumption
Higher versatility
More power in the sense that todays processors are built with
millions of transistors on a single chip.
Need of a microcontroller
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There is no electronic gadget on the earth which is
designed without a microcontroller. For example
communication devices, digital entertainment, portable
devices etc
Personal information products:cell phones, pager, watch ,pocket, recorder, calculator
Laptop components:Mouse , keyboard, modem ,fax card , sound card, battery
charger
Home appliances:Doorlock,alarmclock, thermostat, airconditioner, TV remote,
Refrigrator, microwave oven
Contd..
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Industrial equipments:-Temperature/pressure controllers,
counters, timers, RPM controllers
Toys:- video games, cars, dolls
Test and measurement equipments:-signal generators,multimeters,
frequency counters, oscilloscopes
In Automobiles:-microcontrollers used for engine control,car cruise
control, antilock brakes.
Microprocessor vs Microcontroller
MICROPROCESSOR
MICROCONTROLLER
INTERNAL STRUCTURE
•CPU is standalone ,RAM,ROM,I/O, timer are
separate.
•Microprocessor assimilates the function of a
CPU on a single IC
CPU,RAM,ROM,I/O and timer are all on a single
chip.
Mirocontroller can be considered as a small
computer on an IC
PROCESSING POWER AND MEMORY
•Clock speed:-1GHZ-4GHZ
•RAM:- 512MB-32GB
•ROM:-128GB-2TB
•Peripheral:-UART,USB
•Clock speed:-1MHZ-300MHZ
•RAM:- 2KB-250KB
•ROM:-32KB-2MB
•Peripheral:-UART
POWER CONSUMPTION AND COST
•Power consumption is high bcz of external
devices hence it requires cooling system.
•Overall cost high bcz of requirement of
•Power consumption is low
•Overall cost less as all components are readily
available
Microprocessor vs Microcontroller
MICROPROCESSOR
MICROCONTROLLER
MEMORY ARCHITECTURE
•Microprocessor is based on von-Neumann •Microcontroller is based on harvard
architecture
architecture.
DESIGN
•Flexible from design point of view .i.e •Since there is fixed amount of on chip
designer can decide the amount of RAM,ROM RAM,ROM so it is not so flexible from design
and I/O ports needed to fit the task
point of view.
APPLICATION
•Microprocessor used in general purpose
applications
•It is used in applications where intensive
processing is required
•They are basic components of PCs
•Microcontrollers are dedicated to one task and
run on one specific program
•Microcontroller is application specific not used
in applications where intensive processing is
required.
•They are used in embedded systems.
Contd…
MICROPROCESSOR
MICROCONTROLLER
•They are used in designing general purpose •They are used in automatically controlled
systems and super computers
systems
•Computational capacity of microprocessor is v •Less computational capacity usually used for
high hence can perform complex tasks
simple tasks
•Microprocessor
have
integrated
math •Generally they don’t have math co-processors
coprocessor complex mathematical calculations they used software to perform floating point
which involve floating point arthimetics can be calculations which slows down the devices
performed with graet ease
•Instruction throughput is given higher priority •In contrast microcontrollers are designed to
than interrupt latency.
optimise interrupt latency
•Have few bit manipulation instructions
•They have
instructions.
•Not used in real time systems
•Used to handle real time tasks
numerous
bit
manipulation
Memory architecture classification
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Harvard architecture:- The most obvious characteristic of
harvard architecture is it has physically separate signals ,buses
and storage for code and data memory.
Von-neumann(princeton)architecture:-von-neumann machines
have shared signals ,buses and memory for code and data
thus program can be easily modified by itself since it is stored
in RAM.
Contd…
Instruction set architecture(ISA) Classification
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ISA is a set of processor design techniques used to implement
the instruction work flow on hardware.
It tells us how the processor is going to process instructions for
program.
Two major approaches to processor architecture are CISC and
RISC .
Complex instruction set processors use complex instructions
intended for direct implementation of high level operations.
Reduced instruction set processors design approach uses simple
instructions.
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Common CISC processors are
Intel 8086
Motorola 68xxx
National semiconductor 32xxx
Intel pentium
Common RISC processors are
Freescale/IBM
The ARM
The ATMEL
The Microchip PIC.
Contd…