Design of Embedded Systems An Introduction http://cs.lth.se/EDAN15 Krzysztof Kuchcinski [email protected]Department of Computer Science Lund Institute of Technology Sweden March 19, 2018 Kris Kuchcinski (LTH) Design of Embedded Systems March 19, 2018 1 / 37 Outline 1 Introduction 2 Course Organization 3 General introduction, definition of the field 4 Embedded Systems Examples 5 Embedded Systems Design Methodologies Kris Kuchcinski (LTH) Design of Embedded Systems March 19, 2018 2 / 37 Examples of Embedded Systems Kris Kuchcinski (LTH) Design of Embedded Systems March 19, 2018 3 / 37
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ModemsMPEG decodersNetwork cardsNetwork switches/routersOn-board navigationPagersPhotocopiersPoint-of-sale systemsPortable video gamesPrintersSatellite phonesScannersSmart ovens/dishwashersSpeech recognizersStereo systemsTeleconferencing systemsTelevisionsTemperature controllersTheft tracking systemsTV set-top boxesVCR’s, DVD playersVideo game consolesVideo phonesWashers and dryers
Source: Embedded Systems Design: A UnifiedHardware/Software Introduction, (c) 2000 Vahid/Givargis
Kris Kuchcinski (LTH) Design of Embedded Systems March 19, 2018 4 / 37
Course Organization
Twelve lectures.Four lab assignments plus an introductory lab.
carried out in groups of two studentsuse special software and hardware (lab E:4115 and E:4118)require preparationdeadline for lab reports (last lab assignment) Sunday, May 27,2018, 23:59.
Group day time room1 Wed 10-13 E:41152 Wed 13-15 E:4118
Kris Kuchcinski (LTH) Design of Embedded Systems March 19, 2018 5 / 37
Course Organization (cont’d)
Seminars17/05, 8:15 and 10:15 in E:211624/05, 8:15 and 10:15 in E:2116
Obligatory examinations1 June 2018 at 8-13, Vic:2C, 2D21 August 2018 at 8-13, MA:8C
Books:Peter Marwedel, Embedded System Design, 2nd Edition, Springer,2011 (ISBN: 978-94-007-0256-1).
Kris Kuchcinski (LTH) Design of Embedded Systems March 19, 2018 6 / 37
LecturesPreliminary Schedule
Date Content18-03-19 Introduction, motivation, etc.18-03-23 Design methodology (HW/SW co-design, etc)18-03-26 VHDL introduction18-03-29 VHDL for synthesis18-04-16 Computational models18-04-20 Design representations18-04-23 System partitioning18-04-27 Allocation, assignment18-05-04 and scheduling18-05-07 Communication synthesis18-05-14 Testability18-05-17 Low-power design | ARM presentation
Kris Kuchcinski (LTH) Design of Embedded Systems March 19, 2018 7 / 37
Embedded Systems
“A device that includes a programmable computer but is notitself a general-purpose computer”
Execution deadlines,Power and energy consumption constraints,:
Kris Kuchcinski (LTH) Design of Embedded Systems March 19, 2018 8 / 37
Embedded Systems (cont’d)
Computing systems embedded within electronic devicesHard to define. Nearly any computing system other than adesktop computerBillions of units produced yearly, versus millions of desktop unitsPerhaps 50 per household and per automobile
Source: Embedded Systems Design: A UnifiedHardware/Software Introduction, (c) 2000 Vahid/Givargis
Kris Kuchcinski (LTH) Design of Embedded Systems March 19, 2018 9 / 37
Embedded Systems (cont’d)
Non User-Programmable.Based on programmable components (e.g., Micro-controllers,DSP’s...) but often contain application specific hardware (IC’s,ASIC’s).Reactive Real-Time Systems:
React to external environment,Maintain permanent interaction,Ideally never terminate,Are subject to external timing constraints (real-time).
Kris Kuchcinski (LTH) Design of Embedded Systems March 19, 2018 10 / 37
Characteristics Embedded Systems
Sophisticated functionality.Real-time operation.Low manufacturing cost.Low power.Designed to tight deadlines by small teams."Resource conscious" vs. "Unlimited resources" programming
Kris Kuchcinski (LTH) Design of Embedded Systems March 19, 2018 11 / 37
A Single Processor Embedded System
Source: W. Wolf, Computers as Components:Principles of Embedded Computing Systems Design
Kris Kuchcinski (LTH) Design of Embedded Systems March 19, 2018 12 / 37
SoC Embedded System
Assembly of "prefabricatedcomponent" often purchasedfrom external vendors ("IP")
"black box" hierarchyDesign & Verification at theSystem level
rather than the logic levelInterface andcommunication
Great Importance of Software
Source: Alberto Sangiovanni-Vincentelli, 35th DAC
Kris Kuchcinski (LTH) Design of Embedded Systems March 19, 2018 13 / 37
A Digital Camera Example
Source: F. Vahid and T. Givargis, Embedded System Design: A Unified Hardware Software Approach
Kris Kuchcinski (LTH) Design of Embedded Systems March 19, 2018 14 / 37
Hardwarespeed,power consumption,cost in large volumes,...
Kris Kuchcinski (LTH) Design of Embedded Systems March 19, 2018 24 / 37
Design of Embedded Systems
Need to be done using high-level specification, programming andhardware description languages - not assembly languages andgate/transistor level design.Requires efficient design space exploration andsynthesis/compilation tools.Different design requirements has to be taken into account, e.g.,cost, performance, testability, quality of service, powerconsumption.Multi-language design framework.
Kris Kuchcinski (LTH) Design of Embedded Systems March 19, 2018 25 / 37
Importance of High-Level Design Methods
System Verification Processing Speeds
System implementation Processing time (s/frame)Behavioral model 1 200 (20 min/frame)RTL model 144 000 (1.6 days/frame)Gate model 228 000 (2.6 days/frame)Gate model on hardware accelerator 1 200Rapid prototype 0.5Target hardware 0.05
Source: Paul Clemente, Ron Crevier, Peter Runstadler "RTL andBehavioral Synthesis, A Case Study", VHDL Times, vol. 5, no. 1.
Kris Kuchcinski (LTH) Design of Embedded Systems March 19, 2018 26 / 37
General Design Flow
Specify-Explore-Refine
Kris Kuchcinski (LTH) Design of Embedded Systems March 19, 2018 27 / 37
Specification and Programming
Specification languages, such as UML, SDL.Programming languages, such as C, C++, Java, Esterel, assemblylanguages.Hardware description languages, such as VHDL, Verilog,SystemC.
Example: combining SystemC and C++ gives a unified simulationenvironment for hardware and software.
Kris Kuchcinski (LTH) Design of Embedded Systems March 19, 2018 28 / 37
Hardware Description Languages
Cover several levels of design abstraction as well as behavioraland structural description domain.Contain typical features of programming languages, such as datatypes and program statements.Special features:
time concept,structure description,parallelism.
VHDL (IEEE standard), Verilog, SystemC.
Kris Kuchcinski (LTH) Design of Embedded Systems March 19, 2018 29 / 37
Design Representations(Computational Model)
Used to represent/model digital systems under design.Generated by a compiler from system specification or codeddirectly in the model.Represent the semantics, structure and timing of the system.Usually based on some kind of annotated graph representation.Used internally by design automation systems or by themodeler/designer.
Kris Kuchcinski (LTH) Design of Embedded Systems March 19, 2018 30 / 37
Design – Synthesis
Software is translated into target code for a processor.Real-time operating system might be used.Hardware synthesis – translation of a behavioral representation ofa design into a structural one.Communication synthesis – generates hardware and softwarewhich interconnects system components.
Kris Kuchcinski (LTH) Design of Embedded Systems March 19, 2018 31 / 37
Hardware Synthesis Levels
System level – accepts as an input specification in a form ofcommunicating concurrent processes. The synthesis task is togenerate the general system structure defined by processors,ASIC’s, buses, etc.High level – the input specification is given as a behavioral leveldescription of an algorithm describing the functionality of a designand generates implementation at RT-level. Basic synthesis stepsare scheduling, allocation and binding.Logic level – it can be divided into combinational and sequentiallogic synthesis.Physical design – it accepts a gate-level netlist and produces finalimplementation of the design in a given technology.
Kris Kuchcinski (LTH) Design of Embedded Systems March 19, 2018 32 / 37
Hardware/Software Co-design enablingtechnologies
Software
Microprocessor + code
Hardware
VLSI, ASIC, PLD,...
Assembler, linkers(1950�s, 1960�s)
Machine instructions
Compilers(1960�s, 1970�s)
Assembly instructions
Logic synthesis(1970�s, 1980�s)
Logic gates
RT synthesis(1980�s, 1990�s)
Logic equations/FSM�s
Behavioral synthesis(1990�s)
Register transfer
Sequential program code (e.g., C, VHDL)
Source: F. Vahid and T. Givargis, Embedded System Design: A Unified Hardware Software Approach
Kris Kuchcinski (LTH) Design of Embedded Systems March 19, 2018 33 / 37
Discrete Cosine TransformPartial Design Space
0
1 0
2 0
3 0
4 0
Cloc k
st e ps
M ul
1
M ul
2
M ul
3
M ul
4
Add 4
Add 2
Add 4
Add 3
Add 2
Add 1
Kris Kuchcinski (LTH) Design of Embedded Systems March 19, 2018 34 / 37
Design Space Exploration
0
1 0
2 0
3 0
4 0
Sp
eed
Po
wer
Co
st
Des
ign
tim
e
CPU
CPU
DSP
ASIC
Kris Kuchcinski (LTH) Design of Embedded Systems March 19, 2018 35 / 37
Time-to-market constraint
Market window
Profitneed time for newproduct development,the biggest profit is inthe market window time,missing the marketwindow can be costly
Kris Kuchcinski (LTH) Design of Embedded Systems March 19, 2018 36 / 37
Summary
Embedded systems are important class of electronic systemswhich can be found everywhere,Combine hardware and software solutions,Cover several engineering and research areas: