Srinivas Devadas – författare

The current trend towards the realization of complex and versatile "systems on a chip" requires the combined efforts and attention of experts in a range of areas including microsystems, embedded hardware/software systems, dedicated ASIC and programmable logic hardware, reconfigurable computing, wireless communications and RF issues, video and image processing, memory systems, low power design techniques, design, test and verification algorithms, modeling and simulation, logic synthesis and interconnect analysis. Thus, the contributions presented address a wide range of "systems on a chip" problems. This text comprises the selected proceedings of the Tenth International Conference on Very Large Scale Integration (VLSI '99), which was sponsored by the International Federation for Information Processing (IFIP) and was held in Lisbon, Portugal, in December 1999.The volume is organized around two themes, in which the following topics are addressed: VLSI systems design and applications; analog systems design; analog modelling and design; image processing; reconfigurable computing; memory and system design; low power design VLSI design methods and CAD; test and verification; analog CAD and interconnect; fundamental CAD algorithms; verification and simulation; CAD for physical design; high-level synthesis and verification of embedded systems. This text should be useful reading for researchers working on system integration, design and CAD.

In order to design and build computers that achieve and sustain high performance, it is essential that reliability issues be considered care­ fully. The problem has several aspects. Certainly, considering reliability implies that an engineer must be able to analyze how design decisions affect the incidence of failure. For instance, in order design reliable inte­ gritted circuits, it is necessary to analyze how decisions regarding design rules affect the yield, i.e., the percentage of functional chips obtained by the manufacturing process. Of equal importance in producing reliable computers is the detection of failures in its Very Large Scale Integrated (VLSI) circuit components, caused by errors in the design specification, implementation, or manufacturing processes. Design verification involves the checking of the specification of a design for correctness prior to carrying out an implementation. Implementation verification ensures that the manual design or automatic synthesis process is correct, i.e., the mask-level description correctly implements the specification. Manufacture test involves the checking of the complex fabrication process for correctness, i.e., ensuring that there are no manufacturing defects in the integrated circuit. It should be noted that all the above verification mechanisms deal not only with verifying the functionality of the integrated circuit but also its performance.

This text presents a methodology for low power design. The authors first present a survey of techniques for estimating the average power dissipation of a logic circuit. At the logic level, power dissipation is directly related to average switching activity. A symbolic simulation method that accurately computes the average switching activity in logic circuits is then described. This method is extended to handle sequential logic circuits by modelling correlation in time and by calculating the probabilities of present state lines. The author then presents a survey of methods to optimize logic circuits for low power dissipation which target reduced switching activity. A method to retime a sequential logic circuit where registers are repositioned such that the overall glitching in the circuit is minimized is also described. The author then detail a powerful optimization method that is based on selectively precomputing the output logic values of a circuit one clock cycle before they are required, and using the precomputed value to reduce internal switching activity in the succeeding clock cycle.Presented next is a survey of methods that reduce switching activity in circuits described at the register-transfer and behavioral levels. Also described is a scheduling algorithm that reduces power dissipation by maximising the inactivity period of the modules in a given circuit.

In order to design and build computers that achieve and sustain high performance, it is essential that reliability issues be considered care­ fully. The problem has several aspects. Certainly, considering reliability implies that an engineer must be able to analyze how design decisions affect the incidence of failure. For instance, in order design reliable inte­ gritted circuits, it is necessary to analyze how decisions regarding design rules affect the yield, i.e., the percentage of functional chips obtained by the manufacturing process. Of equal importance in producing reliable computers is the detection of failures in its Very Large Scale Integrated (VLSI) circuit components, caused by errors in the design specification, implementation, or manufacturing processes. Design verification involves the checking of the specification of a design for correctness prior to carrying out an implementation. Implementation verification ensures that the manual design or automatic synthesis process is correct, i.e., the mask-level description correctly implements the specification. Manufacture test involves the checking of the complex fabrication process for correctness, i.e., ensuring that there are no manufacturing defects in the integrated circuit. It should be noted that all the above verification mechanisms deal not only with verifying the functionality of the integrated circuit but also its performance.

Rapid increases in chip complexity, increasingly faster clocks, and the proliferation of portable devices have combined to make power dissipation an important design parameter. The power consumption of a digital system determines its heat dissipation as well as battery life. For some systems, power has become the most critical design constraint. Computer-Aided Design Techniques for Low Power Sequential Logic Circuits presents a methodology for low power design. The authors first present a survey of techniques for estimating the average power dissipation of a logic circuit. At the logic level, power dissipation is directly related to average switching activity. A symbolic simulation method that accurately computes the average switching activity in logic circuits is then described. This method is extended to handle sequential logic circuits by modeling correlation in time and by calculating the probabilities of present state lines. Computer-Aided Design Techniques for Low Power Sequential Logic Circuits then presents a survey of methods to optimize logic circuits for low power dissipation which target reduced switching activity. A method to retime a sequential logic circuit where registers are repositioned such that the overall glitching in the circuit is minimized is also described. The authors then detail a powerful optimization method that is based on selectively precomputing the output logic values of a circuit one clock cycle before they are required, and using the precomputed value to reduce internal switching activity in the succeeding clock cycle. Presented next is a survey of methods that reduce switching activity in circuits described at the register-transfer and behavioral levels. Also described is a scheduling algorithm that reduces power dissipation by maximising the inactivity period of the modules in a given circuit. Computer-Aided Design Techniques for Low Power Sequential Logic Circuits concludes with a summary and directions for future research.