Principles of Asynchronous Circuit Design - A Systems Perspective addresses the need for an introductory text on asynchronous circuit design. Part I is an 8-chapter tutorial which addresses the most important issues for the beginner, including how to think about asynchronous systems. Part II is a 4-chapter introduction to Balsa, a freely-available synthesis system for asynchronous circuits which will enable the reader to get hands-on experience of designing high-level asynchronous systems. Part III offers a number of examples of state-of-the-art asynchronous systems to illustrate what can be built using asynchronous techniques. The examples range from a complete commercial smart card chip to complex microprocessors. The objective in writing this book has been to enable industrial designers with a background in conventional (clocked) design to be able to understand asynchronous design sufficiently to assess what it has to offer and whether it might be advantageous in their next design task.

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Principles of Asynchronous Circuit Design: A Systems Perspective

Asynchronous design has been an active area of research since at least the mid 1950's, but has yet to achieve widespread use. We examine the benefits and problems inherent in asynchronous computations, and in some of the more notable design methodologies. These include Huffman asynchronous circuits, burst-mode circuits, micropipelines, template-based and trace theory-based delay-insensitive circuits, signal transition graphs, change diagrams, and complication-based quasi-delay-insensitive circuits. >

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Asynchronous design methodologies: an overview

Principles of Asynchronous Circuit Design

High-performance parallel computer architecture and systems have been improved at a phenomenal rate. In the meantime, VLSI computer-aided design (CAD) software for multibillion-transistor IC design has become increasingly complex and requires prohibitively high computational resources. Recent studies have shown that, numerous CAD problems, with their high computational complexity, can greatly benefit from the fast-increasing parallel computation capabilities. However, parallel programming imposes big challenges for CAD applications. Fully exploiting the computational power of emerging general-purpose and domain-specific multicore/many-core processor systems, calls for fundamental research and engineering practice across every stage of parallel CAD design, from algorithm exploration, programming models, design-time and run-time environment, to CAD applications, such as verification, optimization, and simulation. This journal special section will cover recent progress on parallel CAD research, including algorithm foundations, programming models, parallel architectural-specific optimization, and verification. More specifically, papers with in-depth and extensive coverage of the following topics will be considered, as well as other topics relevant to the design of parallel CAD algorithms and software tools. 1. Parallel algorithm design and specification for CAD applications 2. Parallel programming models and languages of particular use in CAD 3. Runtime support and performance optimization for CAD applications 4. Parallel architecture-specific design and optimization for CAD applications 5. Parallel program debugging and verification techniques particularly relevant for CAD The papers should be submitted via the Manuscript Central website and should adhere to standard ACM TODAES formatting requirements (http://todaes.acm.org/). The page count limit is 25.

Parallel CAD: Algorithm Design and Programming Special Section Call for Papers TODAES: ACM Transactions on Design Automation of Electronic Systems

Small nxn switches are key components of multistage interconnection networks used in multiprocessors as well as in the communication coprocessors used in multicomputers. The design of the internal buffers in these switches is of critical importance for achieving high throughput low latency communication. We discuss several buffer structures and compare them in terms of implementation complexity and their ability to deal with variations in traffic patterns and message lengths. We present a new design of buffers that provide non-FIFO message handling and efficient storage allocation for variable size packets through the use of linked lists managed by a simple on-chip controller. We evaluate the new buffer design by comparing it to several alternative designs in the context of a multi-stage interconnection network. Our modeling and simulations show that the new buffer outperforms its “competition” and can thus be used to improve the performance of a wide variety of systems currently using less efficient buffers.

High-performance multi-queue buffers for VLSI communications switches

Relative Timing is introduced as an informal method for aggressive asynchronous design. It is demonstrated on three example circuits (C-Element, FIFO, and RAPPID Tag Unit), facilitating transformations from speed-independent circuits to burst-mode, relative timed, and pulse-mode circuits. Relative timing enables improved performance, area, power and testability in all three cases.

http://ieeexplore.ieee.org/iel4/6163/16474/00761535.pdf

Relative timing

The Post Office is an asynchronous, 300000 transistor, full-custom CMOS chip designed as the communication component for the Mayfly scalable parallel processor. Performance requirements led to the development of a design style which permits the design of sequential circuits operating under a restricted form of multiple input change signaling called burst-mode. The Post Office complexity forced the authors to develop a set of design tools capable of correctly synthesizing transistor circuits from state machine and equation specifications, and capable of verifying the correctness of the resultant circuitry using implementation specific timing assumptions. A case study of this design experience is provided. >

The Post Office experience: Designing a large asynchronous chip

This paper describes an investigation of potential advantages and pitfalls of applying an asynchronous design methodology to an advanced microprocessor architecture. A prototype complex instruction set length decoding and steering unit was implemented using self-timed circuits. [The Revolving Asynchronous Pentium/sup (R)/ Processor Instruction Decoder (RAPPID) design implemented the complete Pentium II/sup (R)/ 32-bit MMX instruction set.] The prototype chip was fabricated on a 0.25 /spl mu/m CMOS process and tested successfully. Results show significant advantages - in particular, performance of 2.5-4.5 instructions per nanosecond - with manageable risks using this design technology. The prototype achieves three times the throughput and half the latency, dissipating only half the power and requiring about the same area as the fastest commercial 400 MHz clocked circuit fabricated on the same process.

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An asynchronous instruction length decoder

This paper describes an investigation of potential advantages and risks of applying an aggressive asynchronous design methodology to Intel Architecture. RAPPID ("Revolving Asynchronous Pentium(R) Processor Instruction Decoder"), a prototype IA32 instruction length decoding and steering unit, was implemented using self-timed techniques. RAPPID chip was fabricated on a 0.25 /spl mu/ CMOS process and tested successfully. Results show significant advantages-in particular, performance of 2.5-4.5 instructions/nS-with manageable risks using this design technology. RAPPID achieves three times the throughput and half the latency, dissipating only half the power and requiring about the same area as an existing 400 MHz clocked circuit.

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RAPPID: an asynchronous instruction length decoder

Relative timing (RT) is introduced as a method for asynchronous design Timing requirements of a circuit are made explicit using relative timing Timing can be directly added, removed, and optimized using this style RT synthesis and verification are demonstrated on three example circuits, facilitating transformations from speed-independent circuits to burst-mode and pulse-mode circuits Relative timing enables improved performance, area, power, and functional testability of up to a factor of 3/spl times/ in all three cases This method is the foundation of optimized timed circuit designs used in an industrial test chip, and may be formalized and automated

Kenneth S. Stevens

Papers

Relative timing

The Post Office experience: Designing a large asynchronous chip

An asynchronous instruction length decoder

RAPPID: an asynchronous instruction length decoder

Relative timing [asynchronous design]