Custom Integrated Circuits

Contains reports on nine research projects.Analog Devices, Inc.International Business Machines CorporationJoint Services Electronics Program Contract DAAL03-89-C-0001U.S. Air Force - Office of Scientific Research Contract AFOSR 86-0164BDuPont CorporationNational Science Foundation Grant MIP 88-14612U.S. Navy - Office of Naval Research Contract N00014-87-K-0825American Telephone and TelegraphDigital Equipment CorporationNational Science Foundation Grant MIP 88-5876

Custom Integrated Circuits

Contains reports on twelve research projects.Analog Devices, Inc.International Business Machines, Inc.Joint Services Electronics Program (Contract DAAL03-86-K-0002)Joint Services Electronics Program (Contract DAAL03-89-C-0001)U.S. Air Force - Office of Scientific Research (Grant AFOSR 86-0164)Rockwell International CorporationOKI Semiconductor, Inc.U.S. Navy - Office of Naval Research (Contract N00014-81-K-0742)Charles Stark Draper LaboratoryNational Science Foundation (Grant MIP 84-07285)National Science Foundation (Grant MIP 87-14969)Battelle LaboratoriesNational Science Foundation (Grant MIP 88-14612)DuPont CorporationDefense Advanced Research Projects Agency/U.S. Navy - Office of Naval Research (Contract N00014-87-K-0825)American Telephone and TelegraphDigital Equipment CorporationNational Science Foundation (Grant MIP-88-58764

Custom Integrated Circuits

Contains reports on ten research projects.Analog Devices, Inc.IBM CorporationNational Science Foundation/Defense Advanced Research Projects Agency Grant MIP 88-14612Analog Devices Career Development Assistant ProfessorshipU.S. Navy - Office of Naval Research Contract N0014-87-K-0825AT&TDigital Equipment CorporationNational Science Foundation Grant MIP 88-5876

Optimized synthesis of self-testable finite state machines

A synthesis procedure for self-testable finite state machines is presented. Testability comes under consideration when the behavioral description of the circuit is being transformed into a structural description. To this end, a novel state encoding algorithm, as well as a modified self-test architecture, is developed. Experimental results show that this approach leads to a significant reduction of hardware overhead. Self-testing circuits generally employ linear feedback shift registers for pattern generation. The impact of choosing a particular feedback polynomial on the state encoding is discussed

An efficient procedure for the synthesis of fast self-testable controller structures

The BIST implementation of a conventionally synthesized controller in most cases requires the integration of an additional register only for rest purposes. This leads to some serious drawbacks concerning the fault coverage, the system speed and the area overhead. A synthesis technique is presented which uses the additional test register also to implement the system function by supporting self-testable pipeline-like controller structures. It will be shown, that if the need of two different registers in the final structure is already taken into account during synthesis, then the overall number of flipflops can be reduced, and the fault coverage and system speed call be enhanced. The presented algorithm constructs realizations of a given finite state machine a self-testable structure. The efficiency of the procedure is ensured by a very precise characterization of the space of suitable realizations, which avoids the computational overhead of previously published algorithms

A unified approach for the synthesis of self-testable finite state machines

Conventionally self-test hardware is added after synthesis is completed. For highly sequential circuits like controllers this design method either leads to high hardware overheads or compromises fault coverage. In this paper we outline a unified approach for considering self-test hardware like pattern generators and signature registers during synthesis. Three novel target structures are presented, and a method for designing parallel self-testable circuits is discussed in more detail. For a collection of benchmark circuits we show that hardware overheads for self-testable circuits can be significantly reduced this way without sacrificing testability

The Automatic Synthesis of Fault Tolerant and Fault Secure VLSI Systems

This thesis investigates the design of fault tolerant and fault secure (FTFS) systems within the framework of silicon compilation. Automatic design modification is used to introduce FTFS characteristics into a design. A taxonomy of FTFS techniques is introduced and is used to identify a number of features which an "automatic design for FTFS" system should exhibit. A silicon compilation system, Chip Churn 2 (CC2), has been implemented and has been used to demonstrate the feasibility of automatic design of FTFS systems. The CC2 system provides a design language, simulation facilities and a back-end able to produce CMOS VLSI designs. A number of FTFS design methods have been implemented within the CC2 environment; these methods range from triple modular redundancy to concurrent parity code checking. The FTFS design methods can be applied automatically to general designs in order to realise them as FTFS systems. A number of example designs are presented; these are used to illustrate the FTFS modification techniques which have been implemented. Area results for CMOS devices are presented; this allows the modification methods to be compared. A number of problems arising from the methods are highlighted and some solutions suggested

Evolutionary algorithms for synthesis and optimisation of sequential logic circuits

Considerable progress has been made recently 1n the understanding of combinational logic optimization. Consequently a large number of university and industrial Electric Computing Aided Design (ECAD) programs are now available for optimal logic synthesis of combinational circuits. The progress with sequential logic synthesis and optimization, on the other hand, is considerably less mature. In recent years, evolutionary algorithms have been found to be remarkably effective way of using computers for solving difficult problems. This thesis is, in large part, a concentrated effort to apply this philosophy to the synthesis and optimization of sequential circuits. A state assignment based on the use of a Genetic Algorithm (GA) for the optimal synthesis of sequential circuits is presented. The state assignment determines the structure of the sequential circuit realizing the state machine and therefore its area and performances. The synthesis based on the GA approach produced designs with the smallest area to date. Test results on standard fmite state machine (FS:M) benchmarks show that the GA could generate state assignments, which required on average 15.44% fewer gates and 13.47% fewer literals compared with alternative techniques. Hardware evolution is performed through a succeSSlOn of changes/reconfigurations of elementary components, inter-connectivity and selection of the fittest configurations until the target functionality is reached. The thesis presents new approaches, which combine both genetic algorithm for state assignment and extrinsic Evolvable Hardware (EHW) to design sequential logic circuits. The implemented evolutionary algorithms are able to design logic circuits with size and complexity, which have not been demonstrated in published work. There are still plenty of opportunities to develop this new line of research for the synthesis, optimization and test of novel digital, analogue and mixed circuits. This should lead to a new generation of Electronic Design Automation tools.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

An asynchronous instruction length decoder

Journal ArticleAbstract-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® Processor Instruction Decoder (RAPPID) design implemented the complete Pentium II® 32-bit MMX instruction set.] The prototype chip was fabricated on a 0.25-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