R.E. Bryant proposed a method to handle logic expressions (IEEE Trans. Comp., vol.25, no.8, p.667-91, 1986) which is based on binary decision diagrams (BDD) with restriction; variable ordering ix fixed throughout a diagram. The method is more efficient than other methods proposed so far and depends heavily on variable ordering. A simple but powerful algorithm for variable ordering is developed. The algorithm tries to find a variable ordering which minimizes the number of crosspoints of nets when the circuit diagram is drawn. This is applied to the Boolean comparison of ISCAS benchmark circuits for test pattern generation. The results show that binary decision diagrams (BDD) with the proposed ordering method can verify almost all benchmark circuits in less than several central processor unit (CPU) minutes, which is one hundred times (or more) faster than times reported in the literature. Some techniques for circuit evaluation ordering are also mentioned. >

Evaluation and improvement of Boolean comparison method based on binary decision diagrams

Random logic circuitry (210) is laid out in a logic array (212) that has a plurality of row and column locations. The logic circuitry (210) implements a plurality of dynamic logic circuits, each logic circuit having a plurality of logic gate field effect transistors (224) each formed at a selected intersection of one of the row locations and a predetermined plurality of the column locations. Elongate gate conductors (584-602) are formed at selected row locations in the logic array (212), each gate conductor provided as a gate for one or more of the logic gate transistors (224). Selected ones (e.g. 514, 544) of the transistors are merged in a row direction if the logic does not require them to be isolated from one another. A plurality of elongate second conductors (222) interconnect to selected ones of the sources or drains of the transistors (224). Non-Boolean portions of the logic circuitry are formed in an adjacent tile section (214) in the semiconductor layer separate from the logic array (212). A plurality of river-routed conductors (e.g. AL, F, LL) each connect together a respective array terminal (710, 712), and a terminal of a respective non-Boolean tile.

Comprehensive logic circuit layout system

The automation of the design of electronic systems and circuits [electronic design automation (EDA)] has a history of strong innovation. The EDA business has profoundly influenced the integrated circuit (IC) business and vice-versa. This paper reviews the technologies, algorithms, and methodologies that have been used in EDA tools and the business impact of these technologies. In particular, we focus on four areas that have been key in defining the design methodologies over time: physical design, simulation/verification, synthesis, and test. We then look briefly into the future. Design will evolve toward more software programmability or some other kind of field configurability like field programmable gate arrays (FPGAs). We discuss the kinds of tool sets needed to support design in this environment.

http://files.vlsi.uwindsor.ca/88-559/page6/files/macmillen_tcad00.pdf

An industrial view of electronic design automation

Nanoelectronics research has primarily focused on devices. By contrast, not much has been published on innovations at higher layers: we know little about how to construct circuits or architectures out of such devices. In this paper, we focus on the currently most promising nanodevice technologies, such as arrays of semiconductor nanowires (NWs) and arrays of crossed carbon nanotubes (CNTs). In contrast to general-purpose programmable fabrics (such as PLAs), we investigate nano-fabrics that, while also programmable and hierarchical, are more tuned towards an application domain (in this sense they resemble ASIC). Our goal is to achieve denser designs with better fabric utilization, efficient cascading of circuits, and routing of signals. We demonstrate detailed designs of several circuits and processor data-paths, and highlight associated challenges and opportunities for optimization.

/pdf/opportunities-and-challenges-in-application-tuned-circuits-25utagdguy.pdf

Opportunities and challenges in application-tuned circuits and architectures based on nanodevices

PLATypus (PLA Test pattern generation and logic simulation tool) is an efficient tool for large PLAs which is interfaced with other existing PLA tools such as the constrained/unconstrained, simple/multiple folding program PLEASURE and the logic minimizer ESPRESSO II-C developed at the University of California at Berkeley. PLATYPUS uses biased random test generation as a quick preprocess followed by a deterministic test generation process to achieve the best balance between efficient run time and test set minimality. The algorithm adopted in the deterministic phase is exact, i.e., it achieves the highest possible test coverage by generating a test for every testable fault. Powerful heuristics are introduced in the area of fault processing order, backend fault simulation, “don't-care” bit fixing, and on-the-fly test compaction to achieve the best performance of PLATYPUS. The deterministic test generation algorithm is based on both complementation and tautology check of a logic cover. Both complementation and tautology check are performed by an advanced method used in the logic minimizer ESPRESSO-II. PLATYPUS supports both folded and unfolded PLAs, and both crosspoint and stuck-at fault models. PLATYPUS can also be used as a logic simulation tool and redundancy identifier. Test pattern generation has been performed by PLATYPUS on a large number of industrial PLAs.

PLATYPUS: A PLA Test Pattern Generation Tool

Programmable Logic Arrays are important building blocks of VLSI circuits and systems. We address the problem of optimizing the silicon area and the performances of large logic arrays. In particular we describe a general method for compacting a logic array defined as multiple row and column folding and we address the problem of interconnecting a PLA to the outside circuitry. We define a constrained optimization problem to achieve minimal silicon area occupation with constrained positions of electrical inputs and outputs. We present a new computer program, PLEASURE, which implements several algorithms for multiple and/or constrained PLA folding.

G. DeMichelli

Papers

Pleasure: A Computer Program for Simple/Multiple Constrained/Unconstrained Folding of Programmable Logic Arrays