UNIT-I

1. UNIT-I INTRODUCTION TO EMBEDDED SYSTEM Prof. Prasad mahale

2. OUTLINE • What is an Embedded System? • Applications Areas • Categories of Embedded Systems • Overview of Embedded Systems Architecture • Specialties of Embedded Systems • Recent trends in Embedded Systems • Hardware Architecture • Communication protocols like SPI, SCI, I2C, CAN

3. It is an arrangement in which all its units, assemble work together according to set of rules. • It is a combination of Hardware & Software. • It is design to perform particular task. • The task has to be completed in a given time

4. Introduction to Embedded System (ES) • A System is a way of working, organizing or doing one or many tasks according to a fixed plan, program, or set of rules. • Example: Analog watch • Embedded system can be defined as a computing device that does a specific focused job. • Examples: VCD, DVD player, printer, fax, etc. • Software in ES is always fixed.

6. Embedded systems date back to the 1960s. Charles Stark Draper developed an integrated circuit (IC) in 1961 to reduce the size and weight of the Apollo Guidance Computer, the digital system installed on the Apollo Command Module and Lunar Module. 

7. In 1965, Autonetics, now a part of Boeing, developed the D-17B, the computer used in the Minuteman I missile guidance system.

8. Do very specific or dedicated job. • Have very limited resources like memory, do not have secondary storage). • Specific job completed within specific real time System. • ES are constrained for power. • ES need to be highly reliable. • ES have to operate in extreme environmental condition such as high temp, pressure, humidity, etc.

10. Embedded System (ES) • ES have been defined in several ways: • Wayne Wolf author of Computers as Components –Principles of Embedded Computing System Design: “what is an embedded computing system? Loosely defined, it is any device that includes a programmable computer but is not itself intended to be a general-purpose computer” • Todd D. Morton author of Embedded Microcontroller: “Embedded Systems are electronic systems that contain a microprocessor or microcontroller, but we do not think of them as computers-the computer hidden or embedded in the system.” • David E. Simon author of An Embedded Software Primer: “People use term embedded system to mean any computer system hidden in any of these products.”

11. Tim Wilmshurst author of An introduction to the Design of Small Scale Embedded Systems with examples from PIC, 80C51 and 68HC05/08 microcontrollers: • (a) “An embedded system is a system whose principal function is not computational, but which is controlled by a computer embedded within it.” • (b) “An embedded system is a microcontroller-based, software-driven, reliable, real time control system, autonomous, or human- or network-interactive, operating on diverse physical variables and in diverse environment, and sold into a competitive and cost-conscious market.”

12. Raj Kamal author of Embedded System Architecture, Programming and Design “An Embedded system is a system that has embedded software & computer hardware, which makes it a system dedicated for an application(s) or specific part of an application or a product or a part of larger system” • Main Definition of ES: • An Embedded system is a system that has embedded software & computer hardware or any mechanical parts, which makes it a system dedicated for an application(s) or specific part of an application or a product or a part of larger system”

15. Applications of Embedded System • Nearly 99% of the processors manufactured end up in ES. • Consumer Electronics. • Digital Camera. • Microwave Oven. • Air Conditioner. • High tech car has about to ES for transmission control.(AC, Navigation, etc) • Wrist Watches. • Palmtops (Playing Games and Word Processing) • Office Automation. • Fax Machine. • Modem. • Printer, Scanner, etc.

16. Applications of Embedded System • Industrial Automation. • Industries use ES for process control these include- • Pharmaceutical, nuclear energy, electricity generation and transmission. • To carry out specific task such as • Monitoring the temperature, pressure, humidity, voltage, current, etc and then take appropriate action based on the monitored levels to control other devices.

17. Applications of Embedded System • Medical Electronics. • ECG. • Blood pressure measuring devices, radiation, endoscopy, etc • Development in medical electronics of ES for more accurate diagnosis of diseases. • Computer Networking. • Products such as bridges, routers, ISDN, ATM, X.25 and frame relay switches which implements Data Communication Protocol

18. Applications of Embedded System • Wireless Technologies. • Mobile Communication, mobile phones. • Powerful ES that provide voice communication while we are on move. • PDAs and Palmtops use to access multimedia services over the internet. • Base station controllers, module switching centers are also powerful embedded systems. • Instrumentation. • Testing and measuring are fundamental requirements in all scientific and engineering activities. • We use in laboratories to measure parameters such as weight, temperature, pressure, humidity, voltage, current, etc. • Test equipment such as oscilloscope, spectrum analyzer, logic analyzer, radio communication test set, etc

19. Applications of Embedded System • Security. • Security of persons and info. has always been major issues. • Protect homes, office, airports and also info. we transmit & store. • Biometric system using fingerprint and face recognition are extensively used for authentication as well as for access control in high security buildings. • Finance. • Financial dealing through cash and cheques are now slowly paying way for transactions using Smart Card and ATM. • Smart card of the size of credit card has a small microcontroller and memory and it interact with smart card reader/ATM machine.

20. Applications of Embedded System • Telecommunications. • In telecommunication, the ES can be categorized as subscriber terminals and n/w equipment. • Key telephones, ISDN phones, terminal adapters, web cameras. • Multiplexers, multiple access systems, Packet Assemblers Disassemblers (PADs), satellite modems, etc • IP phone, gateway, gatekeeper are latest ES that provide low cost voice communication over the internet.

21. Examples of embedded systems in daily life • Digital alarm clocks • Electronic parking meters and parking pay stations • Robotic vacuum cleaners (‘robovacs’) • Smart watches and digital wrist watches • Washing machines and dishwashers • Home security systems • Air-conditioners and thermostats • Electric stoves, pressure cookers, and tea/coffee machines • Traffic lights • Vending machines

22. Examples of embedded systems in daily life • Fire alarms and carbon monoxide detectors • Printers, photocopy, fax machines and scanners • Digital and video cameras • Calculators • Remote control gate keys • Digital thermometers • Motion sensors • PDAs and hand-held computers • Lighting systems • GPS navigation devices

23. Examples of embedded systems in daily life • Heart rate monitors and pacemakers • CD players, iPods and MP3 players • Parking lot ticket machines • Cash registers • Digital signature pads • Electronic toys • Refrigerators and freezers • Electronic safes • WiFi routers • Automobile systems (cruise control, anti-lock braking system (ABS), transmission control, electronic fuel injection, suspensions systems, in-vehicle entertainment systems, etc.)

24. Categories of Embedded System

25. Categories of Embedded System • Standalone Embedded System • This type of embedded system works for itself as a device without needing any interconnected computer. • It can take data in the form of analog or digital signals. This system first process data and then outputs data by displaying on the screen. • Microwave ovens • Digital cameras • Mp3 players • Video game consoles • Temperature measurement systems

26. Real Time System • Real time systems are those systems that work within strict time constraints and provide a worst case time estimate for critical situations. • Hard Real Time Embedded System  A Hard Real-Time System guarantees that critical tasks complete on time. • Soft Real Time Embedded System  A Hard Real-Time System guarantees that critical tasks complete on time.

28. Network Information Appliances • These types of embedded systems are related to a network to access the resources. • The connected network can be LAN, WAN or the internet. • The connection can be any wired or wireless. • This type of embedded system is the fastest growing area in embedded system applications. 

30. Mobile Devices • Mobile embedded systems are used in portable embedded devices like cellphones, mobiles, digital cameras MP3 players and personal digital assistants, etc. • The basic limitation of these devices is the other resources and limitation of memory.

31. Overview of Embedded System Architecture • The software residing on memory chip is called firmware. • Integrate the application software with OS and then transfer the entire software on the memory chip.

32. The operating system runs above the hardware & the application software runs above the operating system • Not compulsory to have an OS in every Embedded System • No need of OS for small appliances (remote control units, AC, toys) • For application involving complex processing it is advisable to have an OS. • In such case needs to integrate the application software with the OS & then transfer the entire software onto the memory chip. • Once it transferred to memory chip the software will continuer to run for long time & don’t need to reload a new software

34. 1. CPU:- It can be any of following • Microcontroller • Microprocessor • DSP • The processor unit or central processing unit (CPU) is the unit containing the microprocessor. • This unit interprets the input signals and carries out the control actions according to the program stored in its memory, communicating the decisions as action signals to the outputs. 2. Memory (RAM & ROM):- • Firmware stores in the ROM. • When power is switched on the process reads the ROM. • The program transferred to RAM and the program is executed.

35. 3. Input Devices:- • Input devices have limited capability. • Once we press one key it may reflects specific operation. • It interact with sensors or transducers & produce electric signals that interrupt other system. • 4. Output Devices:- • It has limited capability, Some ES have few LED’s to indicate the health status of system module. • A small LCD may also used to display some important parameters. • 5. Communication interface:- • ES may need to interact other ES or they have transmitted data to desktop. • It includes one or more communication interfaces such as RS 232, RS 422. • The circuit interacts with the processors to carry out the necessary work.

36. Specialities of Embedded System • Reliability • Performance • Power Consumption • Cost • Size • Limited User Interface • Software Upgradation Capability

37. Recent Trends In ES • Most of ES was written only in assembly language and hence writing, debugging and maintaining the code is difficult. • Processor Power. • The growing importance of ES can be gauged by availability of processors. • Powerful 8-bit, 16-bit, 32-bit, 64-bit microcontrollers and microprocessor are cater to different market segments. • The clock speed and the memory addressing capability of the processors are increasing. • Powerful DSP are available for real time analysis of audio and video signals. • Power of Desktop computers is available on Palmtops. • Memory. • Cost of memory chip is reducing day by day. • ES can made functionality rich, having additional feature such as networking protocol and GUI.

38. Operating System. • Advantage of embedding OS is s/w development will fast and maintaining the code is easy. • S/W can developed in high level language such as C. • If real time performance is required a real time OS can be used. • Open source s/w campaign to development of many open source OS. • Communication Interfaces and Networking Capability. • Availability of low cost chips ES can provide network capability through communication interfaces. • Advantages: it can accessed over a n/w for remote control or monitoring. • Upgrading the embedded s/w is easy • Programming Languages. • Development of embedded s/w was done on assembly languages. • Availability of cross compilers. • OO language are catching up. (Java)

39. Development Tools. • Availability of no. of tools for development, debugging and testing as well as for modeling the ES is now giving way for fast development of robust and reliable system. • MATLAB and Simulink. • Java 2 Micro Edition (J2ME) and WAP . • Programmable Hardware. • Programmable Logic Devices(PLDs) and Field Programmable Gate Arrays (FPGAs) giving the way reducing component of an ES. • After developing the prototype mass production of FPGA can be developed which will have all the functionalities of the processor, peripherals as well as application specific circuitry.

40. Hardware Architecture

41. Central Processing Unit • It has two categories • 1. General Purpose Processor (GPP) • 2. Digital Signal Processor • 1. Microprocessor • 2. Microcontroller

42. Central Processing Unit • Register contain the current data and operands that are being manipulated by processor. • In the external memory, processor implements a stack.

43. 1. Arithmetic Logic Unit: • 2. General Purpose Register: • Used to contain current data & operands • Various form of processor (8 bit, 16 bit) • 3. Control Unit: • Fetched instruction from memory to decode them & execute them. • A. Instruction Pointer • B. Stack Pointer • C. Instruction Decoder • D. Memory Address Register & Memory Data Register.

44. Processor Architecture • To do function the processor communicates with other devices using three buses, a bus being a group of signals. • Data Bus- carries the data between processor & other devices. • Address Bus- carries address information from processor to memory • Control and Status Bus- carries the control/ status information like(read or write/ indication error/interrupt signal)

45. Processor Architecture • Von Neuman Architecture Fig: Von Neuman Architecture • Most widely used architecture • It has one memory chip which stored both instruction & data

46. Processor Architecture • Harvard Architecture • Two separate memory blocks • One is program memory & other is data memory • This architecture is much more efficient because accessing the instruction & data will be very fast Fig: Harvard Architecture

47. Processor Architecture • SuperHarvard Architecture • In this architecture the data memory is accessed more frequently than program memory • This architecture provision has been made to store some secondary data in program memory to balance the load Fig: SuperHarvard Architecture

48. Memory • Two Categories: • Program Memory • Data Memory • Memory Chips: • RAM – Random Access Memory • ROM – Read Only Memory • Hybrid Memory

50. RAM • Random Access Memory (RAM) is the best known form of Computer Memory. • The Read and write (R/W) memory of a computer is called RAM. • The User can write information to it and read information from it • SRAM • DRAM