A prologue to Embedded Systems

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A prologue to Embedded Systems Michele Arcuri Software Engineering 2 A.A. 2001-2002

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Outline Introduction Embedded System Design Formal System Specification Introduction to POLIS Design Methodology As illustration that uses a formal framework determination References Glossary

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Introduction Fundamental ideas and definitions What is an inserted framework? Installed System Applications Main qualities Typical Embedded System Constraints Distinctive Embedded System Attributes Reactive Real-Time Embedded Systems

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What is an inserted framework? Inserted System = Computer Inside a Product

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What is an installed framework? An inserted framework utilizes a PC to play out some capacity, however is not utilized (nor saw) as a PC Software is utilized for elements and adaptability Hardware is utilized for execution Typical qualities it plays out a solitary capacity it is a piece of a bigger (controlled) framework cost and unwavering quality are regularly the most huge viewpoints

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Typical Embedded System Organization ADC ASIC DAC FPGA

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Embedded System Applications Consumer gadgets (microwave broiler, camera, ...) Telecommunication exchanging and terminal gear (PDA, ...) Automotive, air spatial (motor control, non-freezing stopping device, ...) Plant control and creation robotization (robot, plant screen, ...) Defense (radar, savvy weapon, ...)

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Typical Embedded System Constraints Small Size, Low Weight Hand-held gadgets Transportation applications – weight costs cash Low Power Battery influence for 8+hours (portable workstations frequently last just 2 hours) Limited cooling may confine influence regardless of the possibility that AC influence accessible Harsh environment Power changes, RF obstruction, lightning Heat, vibration, stun Water, consumption, physical manhandle Safety-basic operation Must capacity effectively Must not work in effectively Extreme cost affectability

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Small Size, Low Weight Embedded PCs are installed in something Form element might be directed by style Electronics might be pressed into whatever space is left over Form element might be persist from past, less-able frameworks Weight might be basic Fuel economy for transportation Comfort for conveyed objects Hardware outline challenges Non-rectangular, 3-D geometries Integrating computerized + simple + influence on single chip for littler size/lighter weight

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Power administration Power is frequently restricted because of influence stockpiling limit "Low Power" desktop CPUs are not by any stretch of the imagination appropriate for some implanted applications 3-7 Watt Low Power Pentium for tablet Less than 1 Watt craved for PDA Less than 1 mW required for some implanted frameworks (may need to run 30 days to 5 years on a battery) Hardware outline challenges Ultra-low influence Fast wake-up when required Low-cost interminable influence era

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Harsh Environment Many inserted frameworks don't have a controlled domain Heat from ignition/constrained cooling Vibration/stun Lightning/Electromagnetic Interference (EMI)/Electrostatic Discharge (ESD) "Dirty" influence supplies Water/erosion Fire Shipping harm Physical mishandle ("drop test") Hardware outline challenges Accurate warm demonstrating Use of various segments for every plan, contingent upon working environment

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Safe and Reliable Systems must be sheltered to ensure individuals and property "Mission-critical" frameworks ~ if gadgets fizzle, somebody could pass on or lose heaps of cash Software and equipment must envision disappointment modes Traditional blame tolerant procedures work, yet are costly Replicated equipment Distributed accord Hw and Sw outline challenges: Realistic dependability expectations with business segments Use of approval strategies (reenactment, formal confirmation,… ) to remedy most mistakes before usage

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Distinctive Embedded System Attributes Reactive : calculation happen in light of outer occasions Periodic events Aperiodic occasions Real Time : rightness is in part an element of time Hard ongoing Absolute due date, past which answer is futile (May incorporate least and greatest time = due date window) Soft continuous Approximate due date Answer corrupts with time contrast from due date Firm continuous Result has no utility outside due date window, yet framework can withstand a couple missed results

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Reactive Real-Time Embedded Systems Maintain a nonstop and perpetual cooperation with nature Must obey timing imperatives managed by the earth Specified as an accumulation of simultaneous modules which converse with each other Implemented utilizing a blend of processors complex peripherals custom equipment and programming

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Embedded System Design The Design Problem System Architecture Traditional Methodology HW/SW Co-Design Methodology Behavior/Architecture Co-Design Methodology

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The Design Problem Deciding the product and equipment engineering for the framework which parts ought to be actualized in programming running on the programmable segments and which ought to be actualized in more particular equipment

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System Architecture Hardware One miniaturized scale controller (to be amplified later… ) ASICs Software Set of simultaneous errands Customized working framework (Real-Time scheduler) Interfaces Hardware modules Software I/O drivers (surveying, intrude on handlers, ...)

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Embedded System Design Traditional Methodology Hardware/Software Partitioning and Allocation HW Design & Build SW Design & Code Interface Design HW/SW Integration

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Problems with Past Design Method Lack of brought together framework level representation Can not check the whole HW-SW framework Hard to discover incongruencies crosswise over HW-SW limit (regularly discovered just when model is constructed) Architecture is characterized from the earlier , in light of master assessment of the usefulness and limitations Lack of very much characterized plan stream Time-to-market issues Specification correction gets to be troublesome

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Embedded System Design HW/SW Co-Design Methodology Hardware/Software Partitioning and Allocation HW Design & Build SW Design & Code Interface Design HW/SW Integration

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Architectural Specifications Architectural Specifications Architectural Specifications Architectural Specifications C HDL Embedded System Design Behavior/Architecture Co-Design Methodology Behavioral Specification Mapping High Level Performance Simulation System Synthesis

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Behavior/Architecture Co-Design Goals Clear division between conduct design correspondence Same structure for detail and behavioral reproduction execution recreation refinement to usage HW, SW and interface union quick prototyping

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Formal System Specification Why a Formal System Specification ? Formal System Specification Formal Model Language Synthesis Mapping from Specification to Architecture Partitioning Hardware and programming amalgamation System Validation Simulation Formal Verification

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Why a Formal System Specification ? In the improvement of installed responsive frameworks the detail of the prerequisites is most basic issue. The dependability of implanted framework relies on upon very much impelled responses as indicated by the clients' desires, even in extraordinary circumstances Embedded frameworks – particularly when running in hazard basic applications – request a high level of unwavering quality Statistics demonstrate that in run of the mill application territories more than half of the glitches that happen are not issues with rightness of usage but rather with misguided judgments in catching the prerequisites ( theoretical necessities mistakes )

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Formal System Specification Main reason: give clear and unambiguous depiction of framework capacity documentation of beginning configuration handle permit the utilization of Computer Aided Design plan space investigation and engineering choice HW/SW dividing HW, SW, interface, RTOS amalgamation approval testing in a perfect world ought not compel the execution

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Formal System Specification Distinguish amongst models and dialects Model decision relies on upon Application area E.g. information stream for computerized flag handling, limited state machines for control, Discrete Event for equipment, ... Dialect decision relies on upon Available apparatuses Personal taste or potentially organization approach Underlying model (the dialect must have a semantics in the picked show)

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Formal Model (in light of L. Lavagno 's articles ) Consist of A practical specificatio n , given as an arrangement of express or understood relations which include data sources, yields and potentially inside (state) data An arrangement of properties that the plan must fulfill, given as an arrangement of relations over information sources, yields, and expresses, that can be checked against the useful particular. An arrangement of execution lists that assess the nature of the outline regarding cost, unwavering quality, speed, estimate, and so on., given as an arrangement of conditions including, in addition to other things, sources of info and yields. An arrangement of requirements on execution records, determined as an arrangement of imbalances.

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Language A dialect depends on an arrangement of images standards for consolidating them (its synta x ) rules for deciphering mixes of images (its semantic s ).

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Synthesis The phase in the outline refinement where a more unique determination is converted into a less theoretical particular For inserted frameworks, blend is a mix of manual and programmed forms, and is frequently separated into three phases mapping to design , in which the general structure of an execution is picked apportioning , in which the segments of a determination are bound to the engineering units equipment and programming amalgamation , in which the points of interest of the units are rounded out

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Mapping from Specification to Architecture The issue of engineering