Synchronization and Arbitration in Digital Systems

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.