1. Introduction to Embedded Systems 1 Jaydeep Patil-AISSMS IOIT Pune

2. Outline 2 What is an embedded system Characteristics and Classification of Embedded Systems Systems-on-a-Chip Distributed Systems Internet-of-Things Embedded Systems Design Challenges Real-Time Embedded Systems Jaydeep Patil-AISSMS IOIT Pune

3. Microprocessors for Embedded systems 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... Jaydeep Patil-AISSMS IOIT Pune

4. Embedded systems overview 4 Embedded computing systems Computing systems embedded within electronic devices Hard to define. Nearly any computing system other than a desktop computer Billions of units produced yearly, versus millions of desktop units Perhaps 50 per household and per automobile A lot more programming is done for embedded systems than desktop computers or servers Computers are in here... and here... and even here... Lots more of these, though they cost a lot less each. Jaydeep Patil-AISSMS IOIT Pune

5. A “short list” 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 Jaydeep Patil-AISSMS IOIT Pune

6. Definitions 6 Broad definition: Any computer system that is not a general-purpose computer That would include robots, and all portable devices Narrow definition: A computer system (software and hardware) that interacts with its physical environment, mainly without human intervention That would exclude printers, modems, portable devices such as dvd and mp3 players, etc. Jaydeep Patil-AISSMS IOIT Pune

7. Some common characteristics of embedded systems 7 Single-functioned Executes a single program, repeatedly Tightly-constrained Low cost, low power, small, fast, etc. Reactive and real-time Continually reacts to changes in the system’s environment Must compute certain results in real-time without delay Jaydeep Patil-AISSMS IOIT Pune

8. Considerations in embedded system design 8 An embedded system receives input from its environment through sensors, processes this input and acts upon its environment through actuators Besides the usual software and hardware design issues the embedded system designer must consider the properties of the sensors and actuators and the environment itself The ultimate test of an embedded systems are the laws of physics Jaydeep Patil-AISSMS IOIT Pune

9. Classification of Embedded Systems 9 Centralized vs distributed Real-time vs non real-time Hard deadline Failsafe Fail-operational Soft deadline Firm deadline Battery powered vs mains powered System-on-Chip vs discrete element Jaydeep Patil-AISSMS IOIT Pune

10. What is real-time? Is there any other kind? 10 A real-time computer system is a computer system where the correctness of the system behavior depends not only on the logical results of the computations, but also on the physical time when these results are produced. By system behavior we mean the sequence of outputs in time of a system. Jaydeep Patil-AISSMS IOIT Pune

11. Real-time means reactive 11  A real-time computer system must react to stimuli from its environment  The instant when a result must be produced is called a deadline.  If a result has utility even after the deadline has passed, the deadline is classified as soft, otherwise it is firm.  If severe consequences could result if a firm deadline is missed, the deadline is called hard.  Example: Consider a traffic signal at a road before a railway crossing. If the traffic signal does not change to red before the train arrives, an accident could result. Jaydeep Patil-AISSMS IOIT Pune

12. Fail-Safe hard-deadline RT systems 12 If a safe state can be identified and quickly reached upon the occurrence of a failure, then we call the system fail-safe. Failsafeness is a characteristic of the controlled object, not the computer system. In case a failure is detected in a railway signaling system, it is possible to set all signals to red and thus stop all the trains in order to bring the system to a safe state. In failsafe applications the computer system must have a high error-detection coverage. Often a watchdog, is required to monitor the operation of the computer system and put it in safe state. Jaydeep Patil-AISSMS IOIT Pune

13. Fail-Operational hard-deadline RT systems 13 In fail-operational applications, threre is no safe state a flight control system aboard an airplane. The computer system must remain operational and provide a minimal level of service even in the case of a failure to avoid a catastrophe Jaydeep Patil-AISSMS IOIT Pune

14. 14 Are the following embedded systems? If yes, classify them. Which characteristics of an embedded system do they have or do not have? Printer DVD player Mobile phone Tablet Netbook/laptop Jaydeep Patil-AISSMS IOIT Pune

15. Typical Embedded System Components 15 Sensors: Allow the system to “read” the environment Processing Elements: Control of the embedded system Actuators: Allow the system to act on its environment Network Connection: Local or internet, allowing exchange of information Jaydeep Patil-AISSMS IOIT Pune

16. An embedded system example – Digital camera 16 Single-functioned -- always a digital camera Tightly-constrained -- Low cost, low power, small, fast Reactive and real-time -- only to a small extent Microcontroller CCD preprocessorPixel coprocessor A2D D2A JPEG codec DMA controller Memory controllerISA bus interfaceUARTLCD ctrl Display ctrl Multiplier/Accum Digital camera chip lens CCD Jaydeep Patil-AISSMS IOIT Pune

17. Embedded Software Development Requires as Much/More Design Effort Than Hardware 17 Jaydeep Patil-AISSMS IOIT Pune

18. A System-on-a-Chip: Example 18 Courtesy: Philips Jaydeep Patil-AISSMS IOIT Pune

19. Design at a crossroad System-on-a-Chip 19 RAM 500 k Gates FPGA + 1 Gbit DRAM Preprocessing Multi- Spectral Imager  C system +2 Gbit DRAM Recog- nition Analog 64 SIMD Processor Array + SRAM Image Conditioning 100 GOPS Embedded applications where cost, performance, and energy are the real issues! DSP and control intensive Mixed-mode Combines programmable and application-specific modules Software plays crucial role Jaydeep Patil-AISSMS IOIT Pune

20. The Future of Embedded Systems 20 In the past an embedded system was more or less isolated In the past decade Wireless Sensor Networks have changed that Today embedded systems + internet connection = Internet of Things ! Near future: Embedded systems + internet + mobile devices + cloud computing + artificial intelligence + ? = smart environment Jaydeep Patil-AISSMS IOIT Pune

21. IoT forecasts 21 Global Internet of Things (IoT) market reached USD 598.2 Billion in 2015 is expected to reach USD 724.2 Billion by 2023 the market is projected to register a CAGR of 13.2% The number of connected IoT (Internet of Things) devices, sensors and actuators will reach over 46 billion in 2021 Jaydeep Patil-AISSMS IOIT Pune

22. IoT 22 Embedded system with internet connection Not quite as simple as it sounds Increased need for security Safety issues Direct machine to machine (M2M) communication Jaydeep Patil-AISSMS IOIT Pune

23. Case studies of distributed embedded systems 23 Jaydeep Patil-AISSMS IOIT Pune

24. Outline 24 Case study 1: RFID Case study 2: Wireless sensor networks Case study 3: Internet of things Jaydeep Patil-AISSMS IOIT Pune

25. RFID Tags 25 Developed to automate the process of object identification electronic tags (called RFID tags) can be read from a small distance by an RFID reader An RFID reader does not require a direct line-of-sight to the RFID tag. The RFID tag stores the unique Electronic Product Code (EPC) of the attached object. Jaydeep Patil-AISSMS IOIT Pune

26. RFID Tag dimensions 26 Since an RFID tag has to be attached to every object, the cost of an RFID tag is a major issue. RFID tags come in various shapes and sizes and continue to decrease in size RFID tags are implantable and implants have been approved in humans as well as animals. Jaydeep Patil-AISSMS IOIT Pune

27. RFID Reader 27 The RFID reader can act as a gateway to the Internet and transmit the object identity, together with the read-time and the object location (i.e., the location of the reader) to a remote computer system that manages a large database. It is thus possible to track objects in real-time Applications: toll gates, hospitals and large organizations, public transportation systems, tracking of animals, libraries Jaydeep Patil-AISSMS IOIT Pune

28. Electronic product code 28 A typical EPC has a length of 96 bits and contains the following fields: Header (8 bits): defines the type and the length of all subsequent fields. EPC Manager (28 bits): specifies the entity (most often the manufacturer) that assigns the object class and serial number in the remaining two fields. Object Class (24 bits): specifies a class of objects (similar to the optical bar code). Object Identification Number (36 bits): contains the serial number within theobject class. The EPC is unique product identification, but does not reveal anything about the properties of the product. Two things that have the same properties, but are designed by two different manufacturers, will have completely different EPCs. Jaydeep Patil-AISSMS IOIT Pune

29. Passive RFID tags 29 Passive RFID Tags. No power supply. They get the power needed for their operation from energy harvested out of the electric field that is beamed on them by the RFID reader. The energy required to operate a passive tag of the latest generation is below 30 mW and the cost of such a tag is below 5 ¢. Due to the low level of the available power and the cost pressure on the production of RFID tags, the communication protocols of passive RFID tags do not conform to the standard Internet protocols. Specially designed communication protocols between the RFID tag and the RFID reader that consider the constraints of passive RFID tags have been standardized by the ISO (e.g., ISO 18000-6C also known as the EPC global Gen 2) and are supported by a number of manufacturers. Jaydeep Patil-AISSMS IOIT Pune

30. Active RFID tags 30 Active RFID Tags have their own on-board power supply The lifetime of an active tag is limited by the lifetime of the battery typically in the order of a year. Active tags can transmit and receive over a longer distance typically in the order of hundreds of meters, can have sensors to monitor their environment sometimes support standard Internet communication protocols. An active RFID tag resembles a small embedded system More expensive Jaydeep Patil-AISSMS IOIT Pune

31. 31 Jaydeep Patil-AISSMS IOIT Pune

32. WSN 32 A set of sensor nodes that each contains a sensor a microcontroller a wireless communication controller Jaydeep Patil-AISSMS IOIT Pune

33. WSN node 33 A sensor node can acquire a variety of physical, chemical, or biological signals to measure properties of its environment. Jaydeep Patil-AISSMS IOIT Pune

34. WSN node constraints 34 Sensor nodes are resource constrained. They are powered either by a small battery or by energy harvested from its environment, have limited computational power, a small memory, and constrained communication capabilities. Jaydeep Patil-AISSMS IOIT Pune

35. WSN deployment and operation 35 a number (from few tens to millions) of sensor nodes are deployed, either systematically or randomly, in a sensor field to form an ad hoc self-organizing network The WSN collects data about the targeted phenomenon and transmits the data via an ad-hoc multi-hop communication channel to one or more base stations that can be connected to the Internet. Jaydeep Patil-AISSMS IOIT Pune

36. WSN function 36 Phase 1: detect neighbors and establish communication Phase 2: learn about the arrangement in which the nodes are connected to each other, the topology of nodes build up ad-hoc multi-hop communication channels to a base station In case of the failure of an active node, it must reconfigure the network Applications: remote environment monitoring, surveillance, medical applications, ambient intelligence, military The utility of a wireless sensor network is in the collective emergent intelligence of all active sensor nodes, not the contribution of any particular node. Jaydeep Patil-AISSMS IOIT Pune

37. Primary concern for WSN: energy 37 A WSN is operational as long as a minimum number of nodes is active and the connectivity of the active nodes to one of the base stations is maintained. In battery-powered sensor networks, the lifetime of the network depends on the energy capacity of the batteries and the power- consumption of a node. When a sensor node has depleted its energy supply, it will cease to function and cannot forward messages to its neighbors any more. The design of the nodes, the communication protocols, and the design of the system and application software for sensor networks are primarily determined by this quest for energy efficiency and low cost. Jaydeep Patil-AISSMS IOIT Pune

38. WSN + RFID = the future? 38 RFID infrastructure for the interconnection of autonomous low-cost RFID-based sensor nodes has been proposed nodes operate without a battery and harvest the energy either from the environment or the electromagnetic radiation emitted by the RFID reader. Potential for long-lasting, low-cost ubiquitous sensor nodes that may revolutionize many embedded applications. Jaydeep Patil-AISSMS IOIT Pune

39. IoT component: Smart object 39 A smart object is a cyber-physical system or an embedded system, consisting of a thing (the physical entity) and a component (the computer) that processes the sensor data and supports a wireless communication link to the Internet. Example: smart refrigerator keeps track of the availability and expiry date of food items and places orders Jaydeep Patil-AISSMS IOIT Pune

40. IoT issues 40 The novelty of the IoT is not in the functional capability of a smart object Novelty exists in the expected size of billions or even trillions of smart objects that bring about novel technical and societal issues that are related to size. issues are: authentic identification of a smart object, autonomic management and self-organization of networks of smart objects, diagnostics and maintenance, intrusion of privacy Safety issues Autonomous mobile robots and self-driving cars Jaydeep Patil-AISSMS IOIT Pune

41. Key technologies for IoT 41 low-power wireless communication: no need of a physical connection. GPS: makes a smart object location- and time-aware Jaydeep Patil-AISSMS IOIT Pune

42. Smart object categories 42 Goal: an autonomic smart object that has access to a domain specific knowledge base is empowered with reasoning capabilities to orient itself in the selected application domain. Based on the capability level of a smart object it can be activity aware policy aware process aware Jaydeep Patil-AISSMS IOIT Pune

43. Ultimate vision: smart planet 43 everyday things around us with an identity in cyberspace capable of acquiring information and intelligence the world economy and support systems will operate more smoothly and efficiently Jaydeep Patil-AISSMS IOIT Pune

44. Social and legal issues in IoT 44 But the life of the average citizen will also be affected by changing the relation of power between those that have access to the acquired information and can control the information and those that do not. IoT devices can be hacked with significant dangers to safety and property Jaydeep Patil-AISSMS IOIT Pune

45. IoT drivers 45 The IoT should extend the interoperability of the internet to the universe of heterogeneous smart objects. Iot must establish a uniform access pattern to things in the physical world. Jaydeep Patil-AISSMS IOIT Pune

46. Logistics 46 The first commercial application of a forerunner of the IoT, the RFID is in the area of logistics There are many quantitative advantages in using RFID technology in supply- chain management: the movement of goods can be tracked in real-time, shelf space can be managed more effectively inventory control is improved the amount of human involvement in the supply chain management is reduced considerably. Jaydeep Patil-AISSMS IOIT Pune

47. Energy savings 47 Already today, embedded systems contribute to energy savings in many different sectors of our economy and our life. increased fuel efficiency of automotive engines, improved energy-efficiency of household appliances, reduced loss in energy conversion The future: of IoT devices opens many new opportunities for energy savings: Smart buildings: individual climate and lighting control in residential buildings Smart grids: reduced energy loss in transmission by the installation of smart grids, Smart meters: better coordination of energy supply and energy demand Other energy savings: Physical meetings replaced by virtual meetings delivery of information goods such as the daily paper, music, and videos by the Internet Jaydeep Patil-AISSMS IOIT Pune

48. Security and safety 48 Automated IoT based access control systems to buildings and homes IoT-based surveillance of public places Smart passports and IoT based identifications (e.g., a smart key to access a hotel room or a smart ski lift ticket) Car-to-car and car-to-infrastructure communication will alert the driver of dangerous traffic scenarios Jaydeep Patil-AISSMS IOIT Pune

49. Industrial 49 computerized observation and monitoring of industrial equipment reduces maintenance cost improves the safety in the plant A smart object can monitor its own operation and call for preventive or spontaneous maintenance in case a part wears out or a physical fault is diagnosed Automated fault-diagnosis and simple maintenance are absolutely essential prerequisites for the wide deployment of the IoT technology in the domain of ambient intelligence. Jaydeep Patil-AISSMS IOIT Pune

50. Medical 50 The wide deployment of IoT technology in the medical domain is anticipated. Health monitoring (heart rate, blood pressure, etc.) precise control of drug delivery by a smart implant Body area networks that are part of the clothing can monitor the behavior of impaired persons and send out alarm messages if an emergency is developing. Smart labels on drugs can help a patient to take the right medication at the right time and enforce drug compliance. Example: A heart pacemaker can transmit important data via a Bluetooth link to a mobile phone that is carried in the shirt pocket. The mobile phone can analyze the data and call a doctor in case an emergency develops. Jaydeep Patil-AISSMS IOIT Pune

51. Technical issues: internet integration 51 Guaranteeing the safety and information security of IoT- based systems is considered to be a difficult task. Many smart objects will be protected from general Internet access by a tight firewall to avoid that an adversary can acquire control of a smart object. Jaydeep Patil-AISSMS IOIT Pune

52. Naming and identification 52 A well-thought-out naming architecture in order to be able to identify a smart object and to establish an access path to the object is essential. Isolated Objects. The following three different object names have to be distinguished when we refer to the simple case of an isolated object: Unique object identifier (UID) refers to the physical identity of a specific object. The Electronic Product Code (EPC) of the RFID community is such a UID. Object type name refers to a class of objects that ideally have the same properties. Object role name. In a given use context, an object plays a specific role that is denoted by the object role name. Jaydeep Patil-AISSMS IOIT Pune

53. Composite object naming 53 Composite Objects. Whenever a number of objects are integrated to form a composite object, a new whole, i.e., new object is created that has an emerging identity that goes beyond the identities of the constituent objects. The composite object resembles a new concept (see Sect. 2.2.1) that requires a new name. Jaydeep Patil-AISSMS IOIT Pune

54. IoT vs cloud computing 54 Smart objects that have access to the Internet can take advantage of services that are offered by the cloud The division of work between a smart object and the cloud will be determined, to a considerable degree, by privacy and energy considerations If the energy required to execute a task locally is larger than the energy required to send the task parameters to a server in the cloud, then the task is a candidate for remote processing. However, there are other aspects that influence the decision about work distribution: autonomy of the smart object, response time, reliability, and security. Jaydeep Patil-AISSMS IOIT Pune

55. Processing Elements used in Embedded Systems 55 Microcontroller: Cheap Optimized for control applications Low processing power Low power consumption General-Purpose Processor: More expensive Medium processing power Suitable but not optimized for any application High power consumption Digital Signal Processor: Optimized for DSP applications (high-end audio, video and image processing) FPGA: Good processing power Longer development time Medium cost Low power consumption ASIC: High processing power Very low power consumption Expensive at low volume Optimized for specific application (hardware accelerators) Long development time Jaydeep Patil-AISSMS IOIT Pune

56. Design challenge – optimizing design metrics 56 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 Jaydeep Patil-AISSMS IOIT Pune

57. Design challenge – optimizing design metrics 57 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 Performance: the execution time or throughput of the system Power: the amount of power consumed by the system Flexibility: the ability to change the functionality of the system without incurring heavy NRE cost Jaydeep Patil-AISSMS IOIT Pune

58. Design challenge – optimizing design metrics 58 Common metrics (continued) Time-to-prototype: the time needed to build a working version of the system Time-to-market: the time required to develop a system to the point that it can be released and sold to customers Maintainability: the ability to modify the system after its initial release Correctness, safety, many more Jaydeep Patil-AISSMS IOIT Pune

59. Design metric competition -- improving one may worsen others 59 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 Microcontroller CCD preprocessorPixel coprocessor A2D D2A JPEG codec DMA controller Memory controllerISA bus interfaceUARTLCD ctrl Display ctrl Multiplier/Accum Digital camera chip lens CCD Jaydeep Patil-AISSMS IOIT Pune

60. Time-to-market: a demanding design metric 60 Time required to develop a product to the point it can be sold to customers Market window Period during which the product would have highest sales Average time-to-market constraint is about 8 months Delays can be costly Revenues ($) Time (months) Jaydeep Patil-AISSMS IOIT Pune

61. Losses due to delayed market entry 61 Simplified revenue model Product life = 2W, peak at W Time of market entry defines a triangle, representing market penetration Triangle area equals revenue Loss The difference between the on- time and delayed triangle areas On-time Delayed entry Peak revenue Peak revenue from delayed entry Market rise Market fall W2W Time D On-time Delayed Revenues ($) Jaydeep Patil-AISSMS IOIT Pune

62. Losses due to delayed market entry (cont.) 62 Area = 1/2 * base * height On-time = 1/2 * 2W * W Delayed = 1/2 * (W-D+W)*(W-D) Percentage revenue loss = (D(3W- D)/2W 2 )*100% Try some examples –Lifetime 2W=52 wks, delay D=4 wks –(4*(3*26 –4)/2*26^2) = 22% –Lifetime 2W=52 wks, delay D=10 wks –(10*(3*26 –10)/2*26^2) = 50% –Delays are costly! On-time Delayed entry Peak revenue Peak revenue from delayed entry Market rise Market fall W2W Time D On-time Delayed Revenues ($) Jaydeep Patil-AISSMS IOIT Pune

63. Real-time (reactive) systems 63 Systems that are bound by a real-time constraint (“deadline”) in their operation If the deadline is not met it is usually considered a system failure, even if the output is eventually correct Deadlines are usually relative to an event Hard deadlines: Anti-lock brakes, Soft deadlines: Digital video Not the same as high-performance systems, because often running faster than real-time requirement is not necessary or desired Jaydeep Patil-AISSMS IOIT Pune

64. Real-time constraints 64 te + to < tc te: execution time to: overhead time tc: constraint time Jaydeep Patil-AISSMS IOIT Pune

65. Example 65 Assuming a real-time system that processes samples at a f= 10 MHz sampling rate, and a to= 20 ns, select the most appropriate implementation among the following: A processor running at 500 MHz, requiring 100 cycles at a cost of 50$ An FPGA running at 200 MHz, requiring 10 cycles at a cost of 60$ A DSP running at 500 MHz, requiring 20 cycles at a cost of 100$ An ASIC running at 2 GHz, requiring 20 cycles at a cost of 500$ Jaydeep Patil-AISSMS IOIT Pune