Modeling and Design of Digital Electronic Systems

The paper is concerned with the modern methodologies for holistic modeling of electronic systems enabling system-on-chip design. The method deals with the functional modeling of complete electronic systems using the behavioral features of Hardware Description Languages or high level languages then targeting programmable devices - mainly Field Programmable Gate Arrays (FPGAs) - for the rapid prototyping of digital electronic controllers. This approach offers major advantages such as: a unique modeling and evaluation environment for complete power systems, the same environment is used for the rapid prototyping of the digital controller, fast design development, short time to market, a CAD platform independent model, reusability of the model/design, generation of valuable IP, high level hardware/software partitioning of the design is enabled, Concurrent Engineering basic rules (unique EDA environment and common design database) are fulfilled. The recent evolution of such design methodologies is marked through references to case studies of electronic system modeling,simulation, controller design and implementation. Pointers for future trends / evolution of electronic design strategies and tools are given

An FPGA Architecture and CAD Flow Supporting Dynamically Controlled Power Gating

© 2015 IEEE.Leakage power is an important component of the total power consumption in field-programmable gate arrays (FPGAs) built using 90-nm and smaller technology nodes. Power gating was shown to be effective at reducing the leakage power. Previous techniques focus on turning OFF unused FPGA resources at configuration time; the benefit of this approach depends on resource utilization. In this paper, we present an FPGA architecture that enables dynamically controlled power gating, in which FPGA resources can be selectively powered down at run-time. This could lead to significant overall energy savings for applications having modules with long idle times. We also present a CAD flow that can be used to map applications to the proposed architecture. We study the area and power tradeoffs by varying the different FPGA architecture parameters and power gating granularity. The proposed CAD flow is used to map a set of benchmark circuits that have multiple power-gated modules to the proposed architecture. Power savings of up to 83% are achievable for these circuits. Finally, we study a control system of a robot that is used in endoscopy. Using the proposed architecture combined with clock gating results in up to 19% energy savings in this application

Unifying mesh- and tree-based programmable interconnect

We examine the traditional, symmetric, Manhattan mesh design for field-programmable gate-array (FPGA) routing along with tree-of-meshes (ToM) and mesh-of-trees (MoT) based designs. All three networks can provide general routing for limited bisection designs (Rent's rule with p<1) and allow locality exploitation. They differ in their detailed topology and use of hierarchy. We show that all three have the same asymptotic wiring requirements. We bound this tightly by providing constructive mappings between routes in one network and routes in another. For example, we show that a (c,p) MoT design can be mapped to a (2c,p) linear population ToM and introduce a corner turn scheme which will make it possible to perform the reverse mapping from any (c,p) linear population ToM to a (2c,p) MoT augmented with a particular set of corner turn switches. One consequence of this latter mapping is a multilayer layout strategy for N-node, linear population ToM designs that requires only /spl Theta/(N) two-dimensional area for any p when given sufficient wiring layers. We further show upper and lower bounds for global mesh routes based on recursive bisection width and show these are within a constant factor of each other and within a constant factor of MoT and ToM layout area. In the process we identify the parameters and characteristics which make the networks different, making it clear there is a unified design continuum in which these networks are simply particular regions

Seven strategies for tolerating highly defective fabrication

In this article we present an architecture that supports fine-grained sparing and resource matching. The base logic structure is a set of interconnected PLAs. The PLAs and their interconnections consist of large arrays of interchangeable nanowires, which serve as programmable product and sum terms and as programmable interconnect links. Each nanowire can have several defective programmable junctions. We can test nanowires for functionality and use only the subset that provides appropriate conductivity and electrical characteristics. We then perform a matching between nanowire junction programmability and application logic needs to use almost all the nanowires even though most of them have defective junctions. We employ seven high-level strategies to achieve this level of defect tolerance

CMOL: Second Life for Silicon?

This report is a brief review of the recent work on architectures for the prospective hybrid CMOS/nanowire/ nanodevice ("CMOL") circuits including digital memories, reconfigurable Boolean-logic circuits, and mixed-signal neuromorphic networks. The basic idea of CMOL circuits is to combine the advantages of CMOS technology (including its flexibility and high fabrication yield) with the extremely high potential density of molecular-scale two-terminal nanodevices. Relatively large critical dimensions of CMOS components and the "bottom-up" approach to nanodevice fabrication may keep CMOL fabrication costs at affordable level. At the same time, the density of active devices in CMOL circuits may be as high as 1012 cm2 and that they may provide an unparalleled information processing performance, up to 1020 operations per cm2 per second, at manageable power consumption.Comment: Submitted on behalf of TIMA Editions (http://irevues.inist.fr/tima-editions

Efficient hardware debugging using parameterized FPGA reconfiguration

Functional errors and bugs inadvertently introduced at the RTL stage of the design process are responsible for the largest fraction of silicon IC re-spins. Thus, comprehensive func- tional verification is the key to reduce development costs and to deliver a product in time. The increasing demands for verification led to an increase in FPGA-based tools that perform emulation. These tools can run at much higher operating frequencies and achieve higher coverage than simulation. However, an important pitfall of the FPGA tools is that they suffer from limited internal signal observability, as only a small and preselected set of signals is guided towards (embedded) trace buffers and observed. This paper proposes a dynamically reconfigurable network of multiplexers that significantly enhance the visibility of internal signals. It allows the designer to dynamically change the small set of internal signals to be observed, virtually enlarging the set of observed signals significantly. These multiplexers occupy minimal space, as they are implemented by the FPGA’s routing infrastructure