The document provides an introduction to embedded systems, explaining their definitions, characteristics, and popular examples across various applications. It discusses the design challenges in optimizing metrics such as cost, size, and performance, as well as the differences between microprocessors and microcontrollers. Ultimately, it emphasizes the necessity of a unified understanding of hardware and software to enhance system design and function.

1. 1
Introduction to Embedded Systems
Sudhanshu Janwadkar, Teaching Asst, SVNIT
Lecture Notes: January 1-4th 2018

2. Outline
2
 Embedded systems overview
 What are they?
 Definition and Examples
 Characteristics of Embedded Systems
 Design Metrics
 Processor Technology
 General Purpose, Single Purpose and Application
Specific processors
 Differences between Microprocessors and
Microcontrollers

3. Embedded systems overview
3
 Computing systems are everywhere
 Most of us think of “desktop” computers
 PC’s
 Laptops
 Mainframes
 Servers
 But there’s another type of computing system
 Far more common...

4. Embedded systems overview
4
 Embedded computing systems
 Computing systems embedded within
electronic devices
 Difficult to define. Nearly any computing
system other than a desktop computer
 Perhaps 100’s of Embedded systems
per household!!!
Embedded System are
involved here...
and here...
and even here...
Lots more of these, though they
cost a lot less each!!!!!
An Embedded System is a system which consists of hardware and
underlying (embedded) software, called firmware, that makes it a system
dedicated for an application or specific part of application or product.

5. Popular Examples of embedded systems
5
And the list goes on and on
Anti-lock brakes
Auto-focus cameras
Automatic teller machines
Automatic toll systems
Automatic transmission
Avionic systems
Battery chargers
Camcorders
Cell phones
Cell-phone base stations
Cordless phones
Cruise control
Curbside check-in systems
Digital cameras
Disk drives
Electronic card readers
Electronic instruments
Electronic toys/games
Factory control
Fax machines
Fingerprint identifiers
Home security systems
Life-support systems
Medical testing systems
Modems
MPEG decoders
Network cards
Network switches/routers
On-board navigation
Pagers
Photocopiers
Point-of-sale systems
Portable video games
Printers
Satellite phones
Scanners
Smart ovens/dishwashers
Speech recognizers
Stereo systems
Teleconferencing systems
Televisions
Temperature controllers
Theft tracking systems
TV set-top boxes
VCR’s, DVD players
Video game consoles
Video phones
Washers and dryers

6. Characteristics of embedded systems
6
 Single-purposed
 Executes a single program, repeatedly
 Traditionally, Embedded Systems were Single Functioned.
 Now a days, the Embedded systems may be Multi-
functioned, but still are single-purposed.
 For example, a washing machine is always a washing
machine. It serves single purpose- i.e. washing clothes.
Multiple functions like variable spin speed, temperature
controlled washing etc may be added for enhancing
user experience, but still the purpose is washing
clothes. It cannot be used for printing characters!

7. Characteristics of embedded systems
7
 Tightly-constrained
 Low cost
 Low power
 Small, size
 Fast etc.
 For example, a mobile phone which doesn’t fit in
pockets may not be desirable. Similarly, a mobile phone
costing Lakhs of rupees may not find market. Or, one
which requires to be charged for hours together, may
not be welcome!

8. Characteristics of embedded systems
8
 Reactive and real-time
 Continually reacts to changes in the system’s
environment
 Must compute certain results in real-time without delay
 An airconditioner is an excellent example
of Real-time and Reactive system.

9. An embedded system example -- a
digital camera
9
Microcontroller
CCD preprocessor Pixel coprocessor
A2D
D2A
JPEG codec
DMA controller
Memory controller ISA bus interface UART LCD ctrl
Display ctrl
Multiplier/Accum
Digital camera chip
lens
CCD
• Single-functioned -- always a digital camera
• Tightly-constrained -- Low cost, low power, small, fast
• Reactive and real-time -- only to a small extent
Note: Images on this slide are only for understanding of the topic.

10. Design challenge – optimizing design
metrics
10
 Obvious design goal:
 Construct an implementation with desired functionality
 Key design challenge:
 Simultaneously optimize numerous design metrics
 Design metric
 A measurable feature of a system’s implementation
 Optimizing design metrics is a key challenge

11. Design challenge – optimizing design
metrics
11
 Common metrics
 Unit cost: the monetary cost of manufacturing each copy of the
system, excluding NRE cost
 NRE cost (Non-Recurring Engineering cost): The one-time
monetary cost of designing the system
 Size: the physical space required by the system. It is measured in
terms of number of transistor for hardware, size of program code
for software.
 Performance: the execution time (software) or throughput
(hardware)
 Power: the amount of power consumed by the system
 Flexibility: the ability to change the functionality of the system
without incurring heavy NRE cost
 Time-to-market: the time required to develop a system to the point
that it can be released and sold to customers
 Correctness, safety, many more

12. Design metric competition -- improving
one may worsen others
12
 Expertise with both software and hardware is needed to
optimize design metrics
 Not just a hardware or software expert, as is common
 A designer must be comfortable with various technologies in order
to choose the best for a given application and constraints
SizePerformance
Power
NRE cost

13. Processor technology
13
 The architecture of the computation engine used to
implement a system’s desired functionality
 Processor does not have to be programmable
 “Processor” not equal to general-purpose processor

14. Processor technology
14
 Processors vary in their customization for the problem at hand
General-purpose
processor
Single-purpose
processor
Application-specific
processor
Desired
functionality

15. General-purpose processors
15
 Programmable device used in a variety of applications
 Also known as “microprocessor”
 Features
 Program memory
 Large registers and general ALU
 User benefits
 Low time-to-market and NRE costs
 High flexibility
 “Pentium” the most well-known, but there are hundreds of
others

16. Single-purpose processors
16
 Digital circuit designed to execute exactly one program
 a.k.a. coprocessor, accelerator or peripheral
 Features
 Contains only the components needed to execute a single
program
 No program memory
 Benefits
 Fast
 Low power
 Small size

17. Application-specific processors
17
 Programmable processor optimized for a particular class
of applications having common characteristics
 Compromise between general-purpose and single-purpose
processors
 Features
 Program memory
 Special functional units
 Benefits
 Some flexibility, good performance, size and power

18. Difference between microprocessor and
microcontroller
18
Organization
 Microprocessor is an IC which has only the CPU (i.e processing
core) inside them. E.g Intel 8085,8086, 80386, i3, i5, i7, i9 etc.
Microprocessors don’t have RAM, ROM, and other peripheral on the
chip. A system designer has to add them externally to make them
functional. Application of microprocessor includes Desktop PC’s,
Laptops, notepads etc.
 On the contrary, Microcontrollers have a CPU(processing core), in
addition with a fixed amount of RAM, ROM and other peripherals, all
embedded on a single chip. They typically found applications in
Embedded Systems


19. Difference between microprocessor and
microcontroller
19
Architecture
 Microprocessors are based on Von-Neumann architecture, where in
program and data are stored in same memory module.
 On the contrary, Microcontrollers are based on Harward achitecture.
Here, code memory and program memory are separate
Von-Neumann Architecture Harward Architecture
Self Study: 1. Pls. list out differences between the two architectures and compare them
2. Justify yourself why 8051 is Harward architecture?

20. Difference between microprocessor and
microcontroller
20
Task performed
 Microcontrollers are designed to perform specific
tasks. Specific means applications where the
relationship of input and output is defined and is
fixed. For example, keyboards, mouse, washing
machine, digicam, remote, microwave etc.
 Since the applications are very specific, they need small resources like
RAM, ROM, I/O ports etc and hence can be embedded on a single chip.
This in turn reduces the size and the cost.
 Microprocessor find applications where tasks are
unspecific like developing software, games,
websites, photo editing, creating documents etc. In
such cases the relationship between input and
output is not defined.
 They need high amount of resources like RAM, ROM, I/O ports etc.

21. Difference between microprocessor and
microcontroller
21
Speed of operation (Clock Frequency)
 The clock speed of the Microprocessor is quite high
as compared to the microcontroller. Whereas the
microcontrollers operate from a few MHz to 30 to 50
MHz, today’s microprocessor operate above 1GHz
as they perform complex tasks.

22. Difference between microprocessor and
microcontroller
22
Cost
 Comparing microcontroller and microprocessor in
terms of cost is not justified. Undoubtedly a
microcontroller is far cheaper than a microprocessor.
 However microcontroller cannot be used in place of
microprocessor and using a microprocessor is not
advised in place of a microcontroller as it makes the
application quite costly.
 Microprocessor cannot be used stand alone. They
need other peripherals like RAM, ROM, buffer, I/O
ports etc and hence a system designed around a
microprocessor is quite costly.

23. Difference between microprocessor and
microcontroller
23
Size and Power Consumption
 In case of Microprocessors, due to a number of
external components connected, the size of the
system is large. Also, these components consume a
lot of power, making them unsuitable candidates for
battery-powered devices as well as other
portable/stand-alone applications.
 The reverse is true for microcontrollers. Typically
most of embedded systems are battery powered and
portable devices. All of the embedded systems are
stand-alone applications.

24. Summary
24
 Embedded systems are everywhere
 Key challenge: optimization of design metrics
 Design metrics compete with one another
 A unified view of hardware and software is necessary to
improve productivity
 Three key technologies
 Processor: general-purpose, application-specific, single-purpose
 Microprocessors vs Microcontrollers