VLSI Design and Test for Systems Dependability
Shojiro Asai Editor
VLSI Design and Test for Systems
Dependability VLSI Design and Test for Systems Dependability
A group picture of participants in the DVLSI Program: researchers from universities, national
laboratories and industry, external program advisors and the staff members of JST are
photographed. 13 March, 2013Shojiro Asai Editor
VLSI Design and Test
for Systems Dependability
Editor Shojiro Asai Rigaku Corporation Tokyo Japan
ISBN 978-4-431-56592-5
ISBN 978-4-431-56594-9 (eBook) https://doi.org/10.1007/978-4-431-56594-9 Library of Congress Control Number: 2017963009 © Springer Japan KK, part of Springer Nature 2019
This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part
of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations,
recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission
or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar
methodology now known or hereafter developed.The use of general descriptive names, registered names, trademarks, service marks, etc. in this
publication does not imply, even in the absence of a specific statement, that such names are exempt from
the relevant protective laws and regulations and therefore free for general use.The publisher, the authors and the editors are safe to assume that the advice and information in this
book are believed to be true and accurate at the date of publication. Neither the publisher nor the
authors or the editors give a warranty, express or implied, with respect to the material contained herein or
for any errors or omissions that may have been made. The publisher remains neutral with regard to
jurisdictional claims in published maps and institutional affiliations. Printed on acid-free paper This Springer imprint is published by the registered company Springer Japan KK part of Springer Nature The registered company address is: Shiroyama Trust Tower, 4-3-1 Toranomon, Minato-ku, TokyoPreface
The technological progress, with its tremendous economic impact, of electronic systems stands out among other industrial products of modern times and has pro- duced various innovations over the last 50 years or so. It has had two major enablers, computer programs and the very-large-scale integration (VLSI) of semi- conductor circuits. The concept of programed computing first materialized in computers that crunched alphanumeric data. The computer program has gone through a remarkable transformation since the introduction of high-level pro- graming languages, close in form to human languages, describing how information is to be processed in the system; translating the program into machine-executable codes became a part of the job of computers. Electronic systems hardware has likewise shown progress in performance at an unprecedented pace starting out from the vacuum tube to the transistor to VLSI. High-performance computers, consisting of thousands of VLSI processors, each one containing billions of transistors, are being used for scientific calculations and big-data analysis. More remarkably, VLSI is used today in a far greater variety of electronic systems. Public infrastructures, such as transportation, utilities, public safety, and telecommunications, are large-scale electronic systems. Consumer items such as cell phones and automo- biles are other examples of advanced electronic systems. All these electronic sys- tems, in contrast to computers used for general computing, are customarily called computer-embedded systems. Progress in the development of these systems has been driven by the evolution of computer software (programing) and electronic hardware (VLSI among others), considered as twin engines working in harmony.
The three most important value metrics of an electronic system are performance, cost (price), and dependability. All three are carefully considered when a user is about to buy a system, or a manufacturer contemplates developing a system for sale. What is meant by performance and cost (price) is obvious and is talked about in terms of straightforward quantitative metrics. The concept of dependability, a term that has evolved from reliability, has expanded its attributes to range from a rela- tively simple quantity, such as mean time to failure (MTTF), a good statistical index of the availability of systems, to far harder to quantify metrics such as safety and vi Preface
important as humans increasingly rely on the convenience and benefit of electronic systems while the scale and severity of the detrimental effects of potential failures in such systems have become more devastating. The purpose of this book is to discuss how design and testing can help mitigate threats to the dependability of VLSI systems. Here the term VLSI system is meant to cover not only VLSI per se but also electronic systems that use VLSI (of semiconductor circuits) as a key component.
This book consists of three parts. Part I is a general introduction to the book and is made up of two chapters. It starts by describing in Chap.
the background and
motivation that led to the undertaking of a government-funded research program entitled, “Fundamental technologies for dependable VLSI systems (called DVLSI hereafter),” funded by the Japan Science and Technology Agency (JST) under the Core Research of Evolutional Science and Technology (CREST) initiative. The program was started in April 2007 and lasted for about 8 years until March 2015, with 11 teams of researchers participating from universities, government labora- tories, and industrial corporations. The rest of Chap.
describes the scope, activ-
ities, and management of the program. Detailed accounts are given as to how overarching issues of dependability were covered, how efforts were made to push expected deliverables toward applications, how exciting industry–academia col- laborations were promoted during the term, and the final outcomes of the program. Chapter
begins with a quick overview of the principles and disciplines of design
and verification/testing of electronic systems. Then, using this as a background, the implications of new technologies developed in the DVLSI program are discussed in light of other emerging trends in technology and the markets.
Part II of this book is entitled, “VLSI Issues in Systems Dependability.” Chapters
discuss various threats to the dependability of VLSIs: ion-
izing radiation, electromagnetic interference, time-dependent degradation, varia- tions in device characteristics, design errors, malicious tampering, etc., and what design and testing can do to manage these threats. Part III, which is entitled,
“Design and Test of VLSI for Systems Dependability,” consists of Chaps.
through
, which describe technologies developed in the program as possible
solutions for dependability in the design and testing of realistic systems such as robots and vehicles, data processing and storage in the cloud environment, wireless public telecommunications with improved connectivity, advanced electronic packaging with wireless interconnect, and so forth. Most chapters and sections of Part II and Part III are authored by the members of research teams in the DVLSI program, but some are contributed by “invited” authors, who, having participated in the various events of the program in one way or other, kindly agreed to express their thoughts in this book.
This book is intended to be a reference for engineers who work on the design and testing of electronic systems with particular attention on dependability. It can be used as an auxiliary textbook in undergraduate and graduate courses as well. It is also hoped that readers of this book with non-engineering backgrounds, such as mathematics and social economists, will gain insight into the problems of systems dependability, and may consider taking them on as innovative challenges. Preface vii
It was a real pleasure to be able to work with the members of the DVLSI program, and to witness industry–university collaborations from inception to frui- tion. I am thankful to numerous speakers from outside the program who gave stimulating talks and shared thoughts and discussions at program conferences. It was good to have been able to interact and exchange ideas with scholars and engineers from various parts of the world (the United States, China, Taiwan, India, and Germany) including active members of the United States program, “Failure-Resistant Systems (FRS)” sponsored by the National Science Foundation (NSF) and the Semiconductor Research Corporation (SRC), and the German pro- gram, “SPP1500 Dependable Embedded Systems,” sponsored by the Deutsche Forschungsgemeinschaft (DFG). I only wish we had closer interactions between these programs—FRS (2013–present), SPP1500 (2012–2016), and DVLSI (2007– 2015)—with more overlapping elements.
My heartfelt thanks go to the following gentlemen: Tohru Kikuno, Atsushi Hasegawa, Masatoshi Ishikawa, Yoshio Masubuchi, Naoki Nishi, Koki Noguchi, Tadayuki Takahashi, Koichiro Takayama, and Kazuo Yano, all of whom are advisory members of the DVLSI program. I would like to thank JST and all its management and staff members for their encouraging and patient support for this program: Kazunori Tsujimoto, Shinobu Masubuchi, Daichi Terashita, Toshiaki Ikoma, Michiharu Nakamura, and the late Koichi Kitazawa, to name but a few.
I would like to thank Toyota Motors Corporation for kindly providing a chart describing the power train of a hybrid vehicle to be used in this book as an illustration, and the Xilinx Company for kindly agreeing that the use of a chart showing an FPGA (Field Programmable Gate Array) coupled with an ARM (ARM is a company that provides an embedded processor architecture) processor, could be included in this book.
I am also thankful to Hikaru Shimura of the Rigaku Corporation who generously allowed me to spend some of my time on the job overseeing this program, and to his technical staff members, of which Kenji Wakasaya was one, who kindly shared their experience in systems design. I am thankful to Binu Thomas of Quest Global, a partner of Rigaku’s in software development, for sharing his thoughts about verification and testing. I cannot thank my colleagues enough at Hitachi Ltd. for stimulating and helping me form ideas about what systems design is. Just to single out a person from the many I worked with, Masayoshih Tsutsumi was an engineer– philosopher who shared his great insight into how to guide thoughts in designing a product, which I have tried to reproduce, only to a very limited extent, in Chap.
.
My last thanks go to Shigeru Oho and Koki Noguchi for thoroughly reviewing the first two chapters and suggesting many important and necessary corrections. Tokyo, Japan
Shojiro Asai March 2017
Contents
Part I Introduction
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Shojiro Asai . . . . . . . .
. . . . . . . . . . . . . .
. . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Shojiro Asai
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . .
. . . . . . . . . .
. . . .
. . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
x Contents
Part II VLSI Issues in Systems Dependability . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Eishi H. Ibe, Shusuke Yoshimoto, Masahiko Yoshimoto, Hiroshi Kawaguchi, Kazutoshi Kobayashi, Jun Furuta, Yukio Mitsuyama, Masanori Hashimoto, Takao Onoye, Hiroyuki Kanbara, Hiroyuki Ochi, Kazutoshi Wakabayashi, Hidetoshi Onodera and Makoto Sugihara
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . .
Makoto Nagata, Nobuyuki Yamasaki, Yusuke Kumura, Shuma Hagiwara and Masayuki Inaba
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . .
Hidetoshi Onodera, Yukiya Miura, Yasuo Sato, Seiji Kajihara, Toshinori Sato, Ken Yano, Yuji Kunitake and Koji Nii . . . . . . . . . . . . . . . . . . . . . . . .
Takashi Sato, Masanori Hashimoto, Shuhei Tanakamaru, Ken Takeuchi, Yasuo Sato, Seiji Kajihara, Masahiko Yoshimoto, Jinwook Jung, Yuta Kimi, Hiroshi Kawaguchi, Hajime Shimada and Jun Yao
. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Contents xi
7 Connectivity in Wireless Telecommunications . . . . . . . . . . . . . . . . . 245
. . . . . . . . . . . . . . .
. . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Kazuo Tsubouchi, Fumiyuki Adachi, Suguru Kameda, Mizuki Motoyoshi, Akinori Taira, Noriharu Suematsu, Tadashi Takagi, Hiroshi Oguma, Minoru Fujishima, Ryuji Inagaki, Masaomi Tsuru, Eiji Taniguchi, Hiroshi Fukumoto, Akira Matsuzawa, Masaya Miyahara, Makoto Iwata, Fumihiro Yamagata and Noboru Izuka
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Hiroki Ishikuro, Tadahiro Kuroda, Atsutake Kosuge, Mitsumasa Koyanagi, Kang Wook Lee, Hiroyuki Hashimoto and Makoto Motoyoshi
. . . . . . . . . . . . . . . . . . . xii Contents
. . . . . . . . . . . . . . . . . . . . . . . .
Masahiro Fujita, Koichiro Takayama, Takeshi Matsumoto, Kosuke Oshima, Satoshi Jo, Michiko Inoue, Tomokazu Yoneda and Yuta Yamato
. . . . .
. . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Takeshi Fujino, Daisuke Suzuki, Yohei Hori, Mitsuru Shiozaki, Masaya Yoshikawa, Toshiya Asai and Masayoshi Yoshimura
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . .
Tomohiro Yoneda, Yoshihiro Nakabo, Nobuyuki Yamasaki, Masayoshi Takasu, Masashi Imai, Suguru Kameda, Hiroshi Oguma, Akinori Taira, Noriharu Suematsu, Tadashi Takagi and Kazuo Tsubouchi
10.4 Verification Method for Tamper-Resistant VLSI Design . . . . . .
11 Test Coverage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 439
. . . . . . . . . . . .
Contents xiii
12 Unknown Threats and Provisions . . . . . . . . . . . . . . . . . . . . . . . . . .
Nobuyasu Kanekawa, Takashi Miyoshi, Masahiro Fujita, Takeshi Matsumoto, Hiroaki Yoshida, Satoshi Jo, Seiji Kajihara, Satoshi Ohtake, Masashi Imai, Tomohiro Yoneda, Hiroyuki Takizawa, Ye Gao, Masayuki Sato, Ryusuke Egawa and Hiroaki Kobayashi
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Part III Design and Test of VLSI for Systems Dependability
13 Design Automation for Reliability . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Masahiro Fujita, Takeshi Matsumoto, Amir Masoud Gharehbaghi, Kosuke Oshima, Satoshi Jo, Hiroaki Yoshida, Takashi Takenaka and Kazutoshi Wakabayashi
Hiroto Yasuura
. . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Masahiko Yoshimoto, Yohei Nakata, Yuta Kimi, Hiroshi Kawaguchi, Makoto Nagata and Koji Nii
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Shuhei Tanakamaru and Ken Takeuchi
Shigeru Oho, Yasuhiro Ito, Yasuo Sugure, Yohei Nakata, Hiroshi Kawaguchi and Masahiko Yoshimoto
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Kazumi Hatayama, Seiji Kajihara, Tomokazu Yoneda, Yuta Yamato, Michiko Inoue, Yasuo Sato, Yukiya Miura and Satoshi Ohtake
xiv Contents
. . . .
. . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Hiroki Ishikuro
Tadahiro Kuroda and Atsutake Kosuge
Tomohiro Yoneda, Masashi Imai, Hiroshi Saito, Akira Mochizuki, Takahiro Hanyu, Kenji Kise and Yuichi Nakamura
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Kenji Kise
Contents xv
. . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Mitsumasa Koyanagi, Hiroaki Kobayashi, Takafumi Aoki, Toshinori Sueyoshi and Tadashi Kamada
. . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Kazuo Tsubouchi, Suguru Kameda, Hiroshi Oguma, Akinori Taira, Noriharu Suematsu and Tadashi Takagi
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . .
. . . . . .
. . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . .
Masahiko Yoshimoto, Go Matsukawa, Yohei Nakata, Hiroshi Kawaguchi, Yasuo Sugure and Shigeru Oho
Nobuyuki Yamasaki, Hiroyuki Chishiro, Keigo Mizotani and Kikuo Wada
xvi Contents
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Koji Nii
. . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . .
Hiroki Hihara, Akira Iwasaki, Masanori Hashimoto, Hiroyuki Ochi, Yukio Mitsuyama, Hidetoshi Onodera, Hiroyuki Kanbara, Kazutoshi Wakabayashi, Tadahiko Sugibayashi, Takashi Takenaka, Hiromitsu Hada and Munehiro Tada
Daisuke Suzuki, Koichi Shimizu and Takeshi Fujino
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Contents xvii
Part I Introduction
Chapter 1 Challenges and Opportunities in VLSI for Systems Dependability Shojiro Asai
Abstract This chapter describes the scope, activities, and results of a research
program entitled, “Fundamental Technologies for Dependable VLSI Systems (DVLSI for short henceforth)” which began in 2007 and ended in 2015. The program, funded by JST (Japan Science and Technology Agency) under the CREST (Core Research of Evolutional Science and Technology) initiative, con- sisted of 11 projects and addressed problems in dependability of electronic systems from various different angles. VLSI is a complex system in its own right and involves a number of potential hazards that arise internally from aging in elements or those that can be caused by external disturbances such as ionizing radiations. Coping with these phenomena has always been a challenge in semiconductor engineering and this program as well. Fabrics (physical structures) robust against threats, bit-error correction methods, and logic-level redundancies have been extensively studied. To go further, challenges of 3-D integration, chip-area (on-chip and across-chip) network, and wireless packaging have been taken on. Exploiting the potential of VLSI in solving problems in systems that call for hard real-time response and/or synchronicity as in robotics and wireless telecommunications has been addressed as new great opportunities for VLSIs. Advanced ways of verifi- cation and test for VLSIs have also been dealt with. We will begin this chapter by going over the background of VLSIs for electronic systems and reviewing the necessity of dependability. We will then describe how this multi-project program of CREST DVLSI was formed and conducted. The university-industry collaboration in goal-oriented management efforts is highlighted as essential. A summary of results obtained follows.
Keywords Dependable system
VLSI CREST University-industry
⋅ ⋅ ⋅
collaboration Goal-oriented management
⋅ S. Asai ( )
✉
Rigaku Corporation, Tokyo, Japan e-mail: [email protected]
4 S. Asai
1.1 VLSI in Electronic Systems and Their Dependability
1.1.1 Pervasiveness of VLSI
The VLSI (Very Large Scale Integration of semiconductor circuits) and software (computer program) are two great enablers of electronic systems, a synonym to modern-day convenience. Personal computers and cell phones, almost indispens- able personal items these days, are good examples. Figure
shows a simplified block diagram of a personal computer. It is seen that VLSI chips such as a
], e.g., RAM (Random
- microprocessor [
Access Memory) and NVM (Nonvolatile Memory), are the most important parts among others. Important peripheral devices such as HDD (Hard Disk Drive), communications control, and monitoring display have built-in processors as well. The PC (Personal Computer) is a typical general-purpose computer where users run various different application programs. High-performance (Super-) computers are at the highest end of general-purpose computers.
Figure
depicts the power train (power generation and transmission) in a
hybrid electric-gasoline-engine vehicle which uses a number of ECUs (electronic control units). Each ECU has at least one microprocessor “embedded” and is thus an electronic system in its own right. The automobile these days is a typical embodiment of embedded computing
]. A high-end car these days uses as many
Purpose Software Hardware Peripheral devices
Application Software WiFi Outputs Processor base station
Compiler RAM
Assembler NVM
Multiple purposes: Printer
Text editing Video/Audio Auxiliary storage Middleware Spreadsheet
SSD or HDD Data analysis Simulation
Communication Backup storage Emailing control
Social networking Operating System Internet trading
Video screen Legend:
Firmware Audio interfaces
VLSI Device Driver
Keyboard/Touchpad
VLSI-embedded Inputs sub-system
Software
PC Personal Computer
Fig. 1.1 A simplified block diagram of a PC (Personal Computer) to illustrate the use of VLSIs as
1 Challenges and Opportunities in VLSI for Systems Dependability
Shift lever position drive request torque motor, generator (Generator) Inverter
5 Regenerative Acceleration pedal brake request regenerative Hybrid ECU value rpm, current voltage Motor ECU Inverter (Motor) Brake ECU regenerative value brake effective engine output voltage SOC,current supply relay Main power electric generator rpm gasoline engine Engine ECU request value motor device power split Battery ECU wheel mechanical power path electrical power path Battery
Fig. 1.2 Electronic control units in the power train of a hybrid electric and gasoline-engine
vehicle to illustrate use of VLSI-powered ECUs (Electronic Control Units). Courtesy, Toyota
Motor Corporationas 80 microprocessors for various subsystem and module-level control
]. Actually,
the VLSI has provided the biggest momentum to improve the quality and reduce the cost of products or services of electronic systems. This is true with most of complex systems products, which may be mechanical (stationary or mobile), aerodynamic, electrical, electromechanical, electromagnetic, optical, electro-optical, or chemical. Because these systems generally need control for precision and throughput, which is hard to achieve were it not for the VLSI and program control. Automobiles, aircrafts, rockets, robots, chemical plants, utilities, medical devices, ATMs (Automatic Teller Machines), data storages, and agricultural plants of today are good examples of computer-embedded systems. They would not have existed without the VLSI as their key components for smart control. It is almost funny that we are accustomed to call these computer-embedded electronic systems “dedicated systems.” Although the purpose of the system is certainly “dedicated”, for example, to automotive control, computers (microprocessors) have actually found far more general and voluminous applications in embedded control than in “general-purpose” computing by PCs and HPCs (High-Performance Computers).
The more the benefits are drawn out of these systems and the more extensive their uses become over the population, the more heavily the human life depends on them. It is necessary therefore to see to it that these systems are available whenever they are needed. Because the VLSI is at the core of these systems as the workhorse,
6 S. Asai
happen if it fails to function as expected, what could be done to prevent serious failures from happening, and what we can innovate further in realizing more dependable systems technologies. Actually, these are the subjects discussed in this book. (Let us call the systems that use VLSIs as key components “electronic systems” hereafter. The term VLSI systems may be used interchangeably.)
1.1.2 Necessity of Dependability
Dependability is never a single quality merit of a system. Central to the merit is rather the “performance” or “performance/cost,” in other words, “better fulfillment
shows the factors that would
of the primary purpose” it is intended for. Table affect the decision a user would make in the procurement of a product or service offered in the marketplace. During early stages of market introduction, cost and or performance may be the most influential factors, but as a product category and its market mature, increased attention is paid to dependability for increased social and economic implications, and this is true now with all kinds of electronic systems. These days, dependability of an electronic system is an interest shared among all those concerned: producers, users, and service providers alike.
The requirements for dependability have been discussed in and among various government regulatory agencies, global/regional/national standards bodies, mission-oriented agencies, industrial associations, and academic societies. Figure
shows such organizations along with the documents they have published. It will be
Table 1.1 Factors affecting the decision-making for procurement of a product or service1 Challenges and Opportunities in VLSI for Systems Dependability Legislature CE marking Regulatory Agencies Standard Bodies
US FDA
IEC 60300 dependability management IEC7 for certain product categories directive, Machine directive Low-voltage directive, EMC Government Body Conformity required Academic/Engineering Societies Special Mission Entities 21 CFR Part 11 electronic records 14 CFR Part 25 airworthiness
US FAA
ISO 26262 road vehicle functional safety IEC 60812 analysis for system reliability ISO 9000 management quality IEC 61508 functional safety ISO MIL-STD-882E system safety US DoD process for civil airborne systems WG10.4 dependable computing Spacecraft safety requirements, ARP4761 safety assessment TCFT fault tolerance,
IEEE
SAE standards IFIP NASA, ESA, JAXA Component Industry Associations Systems Industry Associations Semiconductor test methods AEC Q-100, Q-101, Q-200, etc., JEDEC, JEITA Automotive Electronic Council:
Fig. 1.3 Organizations engaged in regulations, standards, and guidelines for dependability as part
of product qualityrelevant to refer in particular to IEC 60300
] for dependability management, IEC
61508
for functional safety in industrial process measurement, control and
automation, and ISO 26262
] for the functional safety for road vehicles, since these will be frequently cited throughout this book.
1.2 Background and Motivation for the Program
1.2.1 What VLSI Has Brought About—A Historical Perspective
The VLSI has contributed to the progress in electronic systems in so many ways, which may be summarized as follows. #1 Great number of devices integrated on a chip As first observed by Gordon Moore and later named as Moore’s Law that has held up until very recently, the number of transistors integrated on a chip of VLSI silicon has doubled every 18 months [
It is interesting to review the progress that the
VLSI made following what Gordon Moore predicted [
I will not go into that
here, however, since there already are abundant references available for this history
8 S. Asai
]. It is worthwhile to note here, however, that there is a very solid theoretical
background to the scaling down the sizes (other physical parameters and operating voltages as well) of the transistor, the most basic element of VLSI that has underlain its progress
]. The number of transistors in a microprocessor has actually
increased from the mere 2300 of Intel 4004 in 1971 to the billions today
]. The
same is true with memory chips. In no other technologies has it ever been possible to integrate uniformly performing, reliable components the way VLSI has enabled, which has provided the most powerful driving force for the complex electronic systems [
#2 Variety of circuit functions realized on silicon The VLSI rapidly evolved from the early days of chips with a few logic gates into a variety of circuit functions covering arithmetic, logic, memory, analog, and more.
Memories include SRAM (Static Random Access Memory), DRAM (Dynamic Random Access Memory), ROM (Read-Only Memory), EPROM (Electrically Programmable ROM), EEPROM (Electrically Erasable and Programmable ROM), and Flash Memory
]. The analog and analog–digital tier of the silicon circuitry is capable of small-signal and high-power amplification, and analog-to-digital and digital-to-analog conversion
]. A very important type of products of VLSI called
FPGA (Field Programmable Gate Array) emerged during the course of the devel- opment
Image sensors with billions of pixels have been used in cameras
]. Micro-Electro-Mechanical (MEMS) is another direction the VLSI has taken to
develop [ #3 Single-chip implementation of multiple circuit functions Almost all the circuit functions described in #2 have actually been integrated in chips by now in the form of microprocessors used for personal computers, mobile communication devices, and computer-embedded electric, electronic, and software-controlled systems. The CMOS (Complementary Metal-Oxide Semicon- ductor), which emerged originally as low-power but low-speed integrated circuit technology, has since been exploited fully to realize all of the logic, memory, and coupled analog–digital functions, taking over the roles played by ECL, TTL and NMOS, and Bi-CMOS (hybrid bipolar and CMOS), realizing the highest density of integration by virtue of low power (virtually no power consumption when idle) inherent in that technology. This history is very well captured in Table
com-
piled by Makimoto et al. ]. #4 Application functions and accelerated processing During the course of evolution in VLSI, what is now called the ASIC
] has evolved. The ASIC contrasts to
(Application-Specific Integrated Circuit) general-purpose integrated circuits such as standard memories and microprocessors. ASICs with specific system- or subsystem-level functions have often been devel- oped in-house at a systems house, or at a semiconductor house to the order of a systems house, for signal processing in telecom, image-processing applications (rou-
1 Challenges and Opportunities in VLSI for Systems Dependability
9
Table 1.2 Evolution of CMOS to encompass broader applications over time. CMOS has
gradually outperformed other circuit technologies and enabled the integration of various different
circuit functions on a single chip of VLSI [ ]Some of these application functions that were originally developed for ASICS such as efficient display control, encryption, and decryption for secure data transmission have been integrated in a general-purpose microprocessor. There are other types of
VLSIs that evolved into high-performance, dedicated computation to complement microprocessors. In this category are DSP (Digital Signal Processor) [
and GPU
(Graphic Processing Unit) [ #5 Abundance of on-chip resource The availability of an abundance of circuit resource has been exploited to introduce fault tolerance to the VLSI. The use of redundant bits for error correction was first used in DRAMs and SRAMs, easily accommodating a few defective bits to the effect of salvaging partially defective chips and thus drastically lowering the average memory prices. The introduction of error correction dramatically improved the tolerance of semiconductor memories against radiation-induced soft errors.
(Please refer to paragraphs below). The fault-tolerant technology is used in flash memories in a more sophisticated fashion to optimize the memory retention and write–erase endurance. Error-correcting codes and encoding techniques are used to avoid physical interference of charges in the neighboring cells
]. Recent
multiple-processor chips as well as FPGAs are capable of performing redundant concurrent calculation and then having a vote for the correct result to be robust against faults in a part of the chip. Two of most advanced VLSI architectures are shown in Figs.
shows a powerful
integration of a multi-core processor and an FPGA which includes security features such as AES (Advanced Encryption Standard), SHA (Secure Hash Algorithm), and
is a microprocessor for
RSA (Rivest–Shamir–Aldeman encryption) [ automotive applications. Security features to support ISO 26262 have been inte- grated ].
10 S. Asai
Fig. 1.4 A functional block diagram of an integration of a multi-core processor and an FPGA.
Courtesy, Xilinx Corporation
#6 Stable manufacturing and sourcing The remarkable progress in the precision manufacturing technology for semicon- ductors and its rapid proliferation amongst players throughout the world in a competing as well as collaborating business environment has brought about high quality and stability in the sourcing of the VLSI, contributing tremendously to the build, maintenance, and maintenance support of the electric and electronic systems in terms of cost and availability. This has allowed systems houses to use multiple sources to secure procurement of key components.
1 Challenges and Opportunities in VLSI for Systems Dependability
Instruc CPU 7-Stage 2-issue Pipeline, FPU 8KB, 4WAY Op 2.8DMIPS/MHz, 320MHz
11 Local RAM Ɵon Cache Ɵmized for low power 64KB 128bits low latency access, Register Push/Pop instruc Safety ECC, Parity, MPU, Access Guard Global RAM 192KB 64bits access ISO26262 support Ɵon Code Flash Bus 128bits
Code Flash ROM (ECC) CPUSS Core1 PCU I$ (ECC)
LRAM MPU CPU GRAM CPU (ECC) (ECC) FPU LINTC LINTC
Guard
IPIR GINTC CPUSS : CPU Subsystem GRAM : Global RAM LRAM : Local RAM System Bus 64bits (parity) MPU : Memory Protec Peripheral Bus 32bits (parity) GINTC : Global Interrupt Controller LINTC : Local Interrupt Controller IPIR : Inter-Processor Interrupt Register Ɵon Unit
Interrupt PCU : Peripheral Control Unit (MAX 512ch) Request
Fig. 1.5 A functional block diagram of a multiple-core microprocessor for automotive
applications. Various safety and security features such as redundancy and access guard are
integrated to support ISO 26262 for road vehicles. Courtesy, Renesas Electronics#7 Distribution of reusable IPs It has been made possible by the development of commercial practice in the semiconductor industry to distribute the rights to use the whole or parts of the design of an existing VLSI. Commerce of rights to use a semiconductor design (IP, Intellectual Property as it is called) that has proven to work has enabled reuse and helped realize more complicated chips in shorter time and with less cost of development. The last two items (#6 and #7) are a socioeconomic rather than technical phenomenon, which is worth noticing here discussing the impact of
VLSI. Figure
in which a microprocessor IP and an FPGA IP are integrated is a good example.
The progress in VLSI technologies described above has been the contributors to progress in electronic systems, providing ever higher performance at ever lower prices, as well as dependability in compact, integral packages.
12 S. Asai
1.3 Threats and Opportunities for the VLSI Systems
Great many ingenuities and tremendous efforts in engineering and associated sci- ences have been put in to accomplish the colossal tower of VLSI technology as it stands, which has impacted electronic systems with so much socioeconomic momentum.
1.3.1 Threats Arising from Miniaturization
Suppose the precision printing and other manufacturing technologies continue to progress making the transistor and other device features even smaller, the VLSI engineering will be left with a pile of problems as follows to solve. Engineering has negotiated these problems of generic nature so far, but they will be much tougher to cope with in the future. #1 Ionizing radiations and electromagnetic interference There are the issues of various radiations in the environment that causes errors in the VLSI circuits. If a neutron from the outer space hits a VLSI chip, the electronic charges resulting from ionization in the semiconductor could cause errors in the
VLSI circuits that could give rise to a system-level failure. This problem will be dealt with in Chap.
of this book. Electromagnetic interference is another persistent
radiation issue. The voltage change induced by the alternating electromagnetic field generated off-chip (e.g., by an automotive engine igniter) or fed through the power line are a hazard that needs continued attention in the design of the VLSI. This problem will be handled in Chap.
#2 Variations and degradation in device characteristics The variation in sizes and other parameters of the transistor, which become more pronounced as it is scaled down, leads to variation in transistor characteristics, which in turn could cause deviation in delay times in the circuits. The latter could result in a system failure. This problem is addressed in Chap.
. There are also
multiple, persistent mechanisms that cause degradation in the characteristics of transistors and other components in VLSI over time and/or under the stress of operating voltage/current, temperature, etc. The time-dependent degradation mechanisms are the topic of Chap.
.
1.3.2 Threats Arising from Scale and Complexity
Another aspect of problems in