1. EMBEDDED SYSTEM BASICS

2. TOPICS TO BE DISCUSSED System Embedded System Components
Classifications
Processors
Other Hardware
Software
Applications

3. INTRODUCTION What is a system?
A system is a way of working, organizing or doing one or many tasks according to a fixed plan, program or set of rules.
A system is also an arrangement in which all its units assemble and work together according to the plan or program.

4. SYSTEM EXAMPLES WATCH It is a time display SYSTEM
Parts: Hardware, Needles, Battery, Dial,
Chassis and Strap
Rules
All needles move clockwise only
A thin needle rotates every second
A long needle rotates every minute
A short needle rotates every hour
All needles return to the original position after 12 hours

5. SYSTEM EXAMPLES WASHING MACHINE
It is an automatic clothes washing SYSTEM
Parts: Status display panel, Switches & Dials, Motor, Power supply & control unit, Inner water level sensor and solenoid valve.
Rules
Wash by spinning
Rinse
Drying
Wash over by blinking
Each step display the process stage
In case interruption, execute only the remaining

6. EMBEDDED SYSTEM
Definition: An Embedded System is a system that has computer hardware with software embedded in it as one of its important components.
Its software embeds in ROM (Read Only Memory). It does not need secondary memories as in a computer
SOFTWARE PROGRAM
#include <16f876a.h> #use delay (clock= ) #byte PORTB=6 main() { set_tris_b(0); portb=255;        //decimal delay_ms(1000); portb=0x55;        //hexadecimal delay_ms(1000); portb=0b ;  //binary delay_ms(500); }
HARDWARE

7. Embedded System Definitions
“An embedded system is a system that has software embedded into computer-hardware, which makes a system dedicated for an application (s) or specific part of an application or product or part of a larger system.” – Present Book
“An embedded system is one that has a dedicated purpose software embedded in a computer hardware.” – Present Book

8. “It is a dedicated computer based system for an application(s) or product. It may be an independent system or a part of large system. Its software usually embeds into a ROM (Read Only Memory) or flash.” – Present Book
“It is any device that includes a programmable computer but is not itself intended to be a general purpose computer. ” – Wayne Wolf
“Embedded Systems are the electronic systems that contain a microprocessor or a microcontroller, but we do not think of them as computers– the computer is hidden or embedded in the system.” – Todd D. Morton

9. Best Definition of Embedded Systems
“Embedded Systems are the electronic systems that contain a microprocessor or a microcontroller, but we do not think of them as computers– the computer is hidden or embedded in the system.”
It is a combination of Software and Hardware”
It is Specific to an application
E.g. Biometric Finger Print System

10. Embedded System v/s General Purpose System
An embedded system is a microprocessor-based system that is incorporated into a device to monitor and control the functions of the components of the device. They are used in many devices ranging from a microwave oven to a nuclear reactor.
Unlike personal computers that run a variety of applications, embedded systems are designed for performing specific tasks.
An embedded system used in a device (for instance the embedded system in washing machine that is used to cycle through the various states of the washing machine) is programmed by the designers of the system and generally cannot be programmed by the end user.

11. COMPUTER HARDWARE A Microprocessor A Large Memory Input Units
(Primary and Secondary)
(RAM, ROM and caches)
Input Units
(Keyboard, Mouse, Scanner, etc.)
Output Units
(Monitor, printer, etc.)
Networking Units
(Ethernet Card, Drivers, etc.)
I/O Units
(Modem, Fax cum Modem, etc.)

12. COMPONENTS OF EMBEDDED SYSTEM
It has Hardware
Processor, Timers, Interrupt controller, I/O Devices, Memories, Ports, etc.
It has main Application Software
Which may perform concurrently the series of tasks or multiple tasks.
It has Real Time Operating System (RTOS)
RTOS defines the way the system work. Which supervise the application software. It sets the rules during the execution of the application program. A small scale embedded system may not need an RTOS.

13. EMBEDDED SYSTEM HARDWARE

14. EMBEDDED SYSTEM CONSTRAINTS
An embedded system is software designed to keep in view three constraints:
Available system memory
Available processor speed
The need to limit the power dissipation
When running the system continuously in cycles of wait for events, run, stop and wakeup.

15. What makes embedded systems different?
• Real-time operation
• Size
• Cost
• Time
• Reliability
• Safety
• Energy
• Security
• Software up-gradation capability

16. Four example embedded systems with approximate attributes.

17. CLASSIFICATIONS OF EMBEDDED SYSTEM
Small Scale Embedded System
Medium Scale Embedded System
Sophisticated Embedded System

18. SMALL SCALE EMBEDDED SYSTEM
Single 8 bit or 16bit Microcontroller.
Little hardware and software complexity.
They May even be battery operated.
Usually “C” is used for developing these system.
The need to limit power dissipation when system is running continuously.
Programming tools:
Editor, Assembler and Cross Assembler

19. MEDIUM SCALE EMBEDDED SYSTEM
Single or few 16 or 32 bit microcontrollers or Digital Signal Processors (DSP) or Reduced Instructions Set Computers (RISC).
Both hardware and software complexity.
Programming tools:
RTOS, Source code Engineering Tool, Simulator, Debugger and Integrated Development Environment (IDE).

20. SOPHISTICATED EMBEDDED SYSTEM
Enormous hardware and software complexity
Which may need scalable processor or configurable processor and programming logic arrays.
Constrained by the processing speed available in their hardware units.
Programming Tools:
For these systems may not be readily available at a reasonable cost or may not be available at all. A compiler or retargetable compiler might have to be developed for this.

21. PROCESSOR Two Essential Units: Operations
A Processor is the heart of the Embedded System.
For an embedded system designer knowledge of microprocessor and microcontroller is a must.
Two Essential Units: Operations
Control Unit (CU), Fetch
Execution Unit (EU) Execute

22. VARIOUS PROCESSOR 1. General Purpose processor (GPP) Microprocessor
Microcontroller
Embedded Processor
Digital signal Processor
2. Application Specific System Processor (ASSP)
3. Multi Processor System using GPPs

23. MICROPROCESSOR
A microprocessor is a single chip semi conductor device also which is a computer on chip, but not a complete computer.
Its CPU contains an ALU, a program counter, a stack pointer, some working register, a clock timing circuit and interrupt circuit on a single chip.
To make complete micro computer, one must add memory usually ROM and RAM, memory decoder, an oscillator and a number of serial and parallel ports.

24. HISTORY OF MICROPROCESSOR
1st Generation (4 bit processors)
4004 and bit in early 1970 by Intel (Integrated Electronics)
2nd Generation (8 bit processors)
8008 and bit in 1974 Intel with +5 V Input supply  bit
3rd Generation (16 bit processors)
bit. Same as 8086, the 8088 introduced 8088 has only 8 bit data bus
(This made it easier to interface to the common 8 bit peripheral devices available at the time)
Followed by:
The & (16 bit processor), the & (a 32 bit processor), leading to the Pentium range of microprocessors (64 bit processors) available today. The 80x86 and Pentium processors have all been designed for use in personal computer type applications and have large memory maps.

25. VARIOUS MICROPROCESSORS
Intel
4004, 4040
8080, 8085
8086, 8088,
80186, 80188
80286, 80386
x86-64
Motorola
6800
6809
68000
G3, G4, G5
Zilog
Z80, Z180, eZ80
Z8, eZ8
and others

26. MICROCONTROLLER
A microcontroller is a functional computer system-on-a-chip. It contains a processor, memory, and programmable input/output peripherals.
Microcontrollers include an integrated CPU, memory (a small amount of RAM, program memory, or both) and peripherals capable of input and output.

27. VARIOUS MICROCONTROLLERS
INTEL
8031,8032,8051,8052,8751,8752
PIC
8-bit PIC16, PIC18,
16-bit DSPIC33 / PIC24,
PIC16C7x
Motorola
MC68HC11

28. MICROPROCESSOR Vs MICROCONTROLLER
The functional blocks are ALU, registers, timing & control units
It includes functional blocks of microprocessors & in addition has timer, parallel i/o, RAM, EPROM, ADC & DAC
Bit handling instruction is less, One or two type only
Many type of bit handling instruction
Rapid movements of code and data between external memory & MP
Rapid movements of code and data within MC
It is used for designing general purpose digital computers system
They are used for designing application specific dedicated systems

29. EMBEDDED PROCESSOR
Special microprocessors & microcontrollers often called, Embedded processors.
An embedded processor is used when fast processing fast context-switching & atomic ALU operations are needed.
Examples : ARM 7, INTEL i960, AMD

30. DIGITAL SIGNAL PROCESSOR
DSP as a GPP is a single chip VLSI unit.
It includes the computational capabilities of microprocessor and multiply & accumulate units (MAC).
DSP has large number of applications such as image processing, audio, video & telecommunication processing systems.
It is used when signal processing functions are to be processed fast.
Examples : TMS320Cxx

31. APPLICATION SPECIFIC SYSTEM PROCESSOR (ASSP)
ASSP is dedicated to specific tasks and provides a faster solution.
An ASSP is used as an additional processing unit for running the application in place of using embedded software.
Examples : W3100A

32. MULTI PROCESSOR SYSTEM USING GPPs
Multiple processors are used when a single processor does not meet the needs of different task.
The operations of all the processors are synchronized to obtain an optimum performance.

33. Design Processes And Design Metric For An Embedded-system Design

34. DESIGN PROCESSES IN EMBEDDED SYSTEM
Abstraction
Hardware & Software
Extra functional Properties
System Related Family of designs:
Modular Design
Mapping
User interface Design
Refinements

35. Abstraction Each problem component first abstracted.
For example, Display picture and text as an abstract class
Robotic system problem abstraction in terms of control of motors in different degrees of freedoms.
Application software abstracted as concurrently running multiple threads and interrupt service threads

36. Hardware and Software architecture
Assumed to consists multiple layers
Each architectural layer be well understood before a design

37. Extra functional Properties
Extra functionalities required in the system being developed be well understood from the design.

38. Modular Design
Decomposition of software into modules that are to be implemented.
Modules should be such that they can be composed (coupled or integrated) later.
Effective Modular design should ensure effective (i) Function independence, (ii) Cohesion( It is a measure of how strongly-related each piece of functionality expressed by the source code of a software module is)
(iii) Coupling.

39. Modules Be clearly understood and maintain continuity.
Appropriate protection strategies are necessary for each module. A module is not permitted to change or modify another module functionality.
For example, protection from a device driver modifying the configuration of another device

40. Mapping
Mapping into various representations done considering the software requirements.
For example, an image is input data to a system; it can have a different number of pixels and colors of each pixel. The system has to store or process each pixel and color Transform mapping of image is done by appropriate compression and storage algorithms.
Transaction mapping is done to define the sequence of the images

41. User Interfaces Design
Designed as per user requirements, analysis of the environment and system functions.
For example, in an automatic chocolate vending machine(ACVM) system, the user interface is a LCD matrix display. It can display a welcome message as well as specify the coins needed to be inserted into the machine for each type of chocolate. Same ACVM may be designed with touch screen GUI.
Same ACVM may be designed with Voice User Interfaces (VUIs). A GUI or VUI or user interface or LCD matrix display

42. Refinements
Each component and module design needs to be refined iteratively till it becomes the most appropriate for implementation by the software team.

43. OTHER HARDWARE Power Source Clock Oscillator Real Time Clock (RTC)
Reset Circuit, Power-up Reset and watchdog timer Reset
Memory
I/O Ports, I/O Buses
Interrupt Handler
DAC and ADC
LCD and LED Display
Keypad/Keyboard

44. 1. Power Supply
System own supply with separate supply rails for IOs, clock, basic processor and memory and analog units,
Supply from a system to which the embedded system interfaces
Charge pump concept used in a system of little power needs.
A Charge Pump is an electronic circuit that converts the supply voltage VDD to a DC output voltage Vout that is several times higher than VDD (i.e., it is a DC-DC converter whose input voltage is lower than the output one).

45. Circuit of Charge Pump
CPs are only made of capacitors and switches (or diodes), thereby allowing integration on silicon.

46. 2. Clock Oscillator Circuit and Clocking Units
Appropriate clock oscillator circuit
Real Time Clock*( System Clock) and Timers driving hardware and software.
A timer circuit is suitably configured as the real time clock (RTC) that generates system interrupts periodically for the schedulers.

47. 3. Reset Circuit Reset on Power-up External and Internal Reset circuit
It means on switching-on reset of the system or on detection of low voltage.
External and Internal Reset circuit
Reset on Timeout of Watchdog timer.

48. SOFTWARE
SOFTWARE C
C++
Dot Net
SIMULATOR
Masm
COMPILER
RIDE
KEIL

49. APPLICATIONS Household appliances:
Microwave ovens, Television, DVD Players & Recorders
Audio players
Integrated systems in aircrafts and
missiles
Cellular telephones
Electric and Electronic Motor controllers
Engine controllers in automobiles
Calculators
Medical equipments
Videogames
Digital musical instruments, etc.