Synchronization and Arbitration in Digital Systems

Today s networks of processors on and off chip, operating with independent clocks, need effective synchronization of the data passing between them for reliability. When two or more processors request access to a common resource, such as a memory, an arbiter has to decide which request to deal with first. Current developments in integrated circuit processing are leading to an increase in the numbers of independent digital processing elements in a single system. With this comes faster communications, more networks on chip, and the demand for more reliable, more complex, and higher performance synchronizers and arbiters. Written by one of the foremost researchers in this area of digital design, this authoritative text provides in-depth theory and practical design solutions for the reliable working of synchronization and arbitration hardware in digital systems. The book provides methods for making real reliability measurements both on and off chip, evaluating some of the common difficulties and detailing circuit solutions at both circuit and system levels. Synchronization and Arbitration in Digital Systems also presents: mathematical models used to estimate mean time between failures in digital systems; a summary of serial and parallel communication techniques for on-chip data transmission; explanations on how to design a wrapper for a locally synchronous cell, highlighting the issues associated with stoppable clocks; an examination of various types of priority arbiters, using signal transition graphs to show the specification of different designs (from the simplest to more complex multi-way arbiters) including ways of solving problems encountered in a wide range of applications; essential information on systems composed of independently timed regions, including a discussion on the problem of choice and the factors affecting the time taken to make choices in electronics. With its logical approach to design methodology, this will prove an invaluable guide for electronic and computer engineers and researchers working on the design of digital electronic hardware. Postgraduates and senior undergraduate students studying digital systems design as part of their electronic engineering course will struggle to find a resource that better details the information given inside this book

Today's networks of processors on and off chip, operatingwith independent clocks, need effective synchronization of the datapassing between them for reliability. When two or more processorsrequest access to a common resource, such as a memory, an arbiterhas to decide which request to deal with first. Currentdevelopments in integrated circuit processing are leading to anincrease in the numbers of independent digital processing elementsin a single system. With this comes faster communications, morenetworks on chip, and the demand for more reliable, more complexand higher performance synchronizers and arbiters. Written by oneof the foremost researchers in this area of digital design, thisauthoritative text provides in-depth theory and practical designsolutions for the reliable working of synchronization andarbitration hardware in digital systems.The book provides methods for making real reliabilitymeasurements both on and off chip, evaluating some of the commondifficulties and detailing circuit solutions at both circuit andsystem levels. Synchronization and Arbitration in DigitalSystems also presents:* mathematical models used to estimate mean time between failuresin digital systems;* a summary of serial and parallel communication techniques foron-chip data transmission;* explanations on how to design a wrapper for a locallysynchronous cell, highlighting the issues associated with stoppableclocks;* an examination of various types of priority arbiters, usingsignal transition graphs to show the specification of differentdesigns (from the simplest to more complex multi-way arbiters)including ways of solving problems encountered in a wide range ofapplications;* essential information on systems composed of independentlytimed regions, including a discussion on the problem of choice andthe factors affecting the time taken to make choices inelectronics.With its logical approach to design methodology, this will provean invaluable guide for electronic and computer engineers andresearchers working on the design of digital electronic hardware.Postgraduates and senior undergraduate students studying digitalsystems design as part of their electronic engineering course willstruggle to find a resource that better details the informationgiven inside this book

Preface.List of Contributors.Acknowledgements.1. Synchronization, Arbitration and Choice.1.1 Introduction.1.2 The Problem of Choice.1.3 Choice in Electronics.1.4 Arbitration.1.5 Continuous and Discrete Quantities.1.6 Timing.1.7 Book Structure.PART I.2. Modelling Metastability.2.1 The Synchronizer.2.2 Latch Model.2.3 Failure Rates.2.3.1 Event Histograms and MTBF.2.4 Latches and Flip-flops.2.5 Clock Back Edge.3. Circuits.3.1 Latches and Metastability Filters.3.2 Effects of Filtering.3.3 The Jamb Latch.3.3.1 Jamb Latch Flip-flop.3.4 Low Coupling Latch.3.5 The Q-flop.3.6 The MUTEX.3.7 Robust Synchronizer.3.8 The Tri-flop.4. Noise and its Effects.4.1 Noise.4.2 Effect of Noise on a Synchronizer.4.3 Malicious Inputs.4.3.1 Synchronous Systems.4.3.2 Asynchronous Systems.5. Metastability Measurements.5.1 Circuit Simulation.5.1.1 Time Step Control.5.1.2 Long-term τ.5.1.3 Using Bisection.5.2 Synchronizer Flip-flop Testing.5.3 Rising and Falling Edges.5.4 Delay-based Measurement.5.5 Deep Metastability.5.6 Back Edge Measurement.5.7 Measure and Select.5.7.1 Failure Measurement.5.7.2 Synchronizer Selection.6. Conclusions Part I.PART II.7. Synchronizers in Systems.7.1 Latency and Throughput.7.2 FIFO Synchronizer.7.3 Avoiding Synchronization.7.4 Predictive Synchronizers.7.5 Other Low-latency Synchronizers.7.5.1 Locally Delayed Latching (LDL).7.5.2 Speculative Synchronization.7.6 Asynchronous Communication Mechanisms (ACM).7.6.1 Slot Mechanisms.7.6.2 Three-slot Mechanism.7.6.3 Four-slot Mechanism.7.6.4 Hardware Design and Metastability.7.7 Some Common Synchronizer Design Issues.7.7.1 Unsynchronized Paths.7.7.2 Moving Metastability Out of Sight.7.7.3 Multiple Synchronizer Flops.8. Networks and Interconnects.8.1 Communication on Chip.8.1.1 Comparison of Network Architectures.8.2 Interconnect Links.8.3 Serial Links.8.3.1 Using One Line.8.3.2 Using Two Lines.8.4 Differential Signalling.8.5 Parallel Links.8.5.1 One Hot Codes.8.5.2 Transition Signaling.8.5.3 n of m Codes.8.5.4 Phase Encoding.8.5.5 Time Encoding.8.6 Parallel Serial Links.9. Pausible and Stoppable Clocks in GALS.9.1 GALS Clock Generators.9.2 Clock Tree Delays.9.3 A GALS Wrapper.10. Conclusions Part II.PART III.11. Arbitration.11.1 Introduction.11.2 Arbiter Definition.11.3 Arbiter Applications, Resource Allocation Policies and Common Architectures.11.4 Signal Transition Graphs, Our Main Modelling Language.12. Simple Two-way Arbiters.12.1 Basic Concepts and Conventions.12.1.1 Two-phase or Non-return-to-zero (NRZ) Protocols.12.1.2 Four-phase or Return-to-zero (RTZ) Protocols.12.2 Simple Arbitration Between Two Asynchronous Requests.12.3 Sampling the Logic Level of an Asynchronous Request.12.4 Summary of Two-way Arbiters.13. Multi-way Arbiters.13.1 Multi-way MUTEX Using a Mesh.13.2 Cascaded Tree Arbiters.13.3 Ring-based Arbiters.14. Priority Arbiters.14.1 Introduction.14.2 Priority Discipline.14.3 Daisy-chain Arbiter.14.4 Ordered Arbiter.14.5 Canonical Structure of Priority Arbiters.14.6 Static Priority Arbiter.14.7 Dynamic Priority Arbiter.15. Conclusions Part III.References.Index.