Konstantinos Tatas

Data-Reuse and Parallel Embedded Architectures for Low-Power, Real-Time Multimedia Applications

Exploitation of data re-use in combination with the use of custom memory hierarchy that exploits the temporal locality of data accesses may introduce significant power savings, especially for data-intensive applications. The effect of the data-reuse decisions on the power dissipation but also on area and performance of multimedia applications realized on multiple embedded cores is explored. The interaction between the data-reuse decisions and the selection of a certain data-memory architecture model is also studied. As demonstrator a widely-used video processing algorithmic kernel, namely the full search motion estimation kernel, is used. Experimental results prove that improvements in both power and performance can be acquired, when the right combination of data memory architecture model and data-reuse transformation is selected.

Designing 2D and 3D Network-on-Chip Architectures

This book covers key concepts in the design of 2D and 3D Network-on-Chip interconnect. It highlights design challenges and discusses fundamentals of NoC technology, including architectures, algorithms and tools. Coverage focuses on topology exploration for both 2D and 3D NoCs, routing algorithms, NoC router design, NoC-based system integration, verification and testing, and NoC reliability. Case studies are used to illuminate new design methodologies.

DAGGER: a novel generic methodology for FPGA bitstream generation and its software tool implementation

A novel bitstream generation algorithm and its software implementation are introduced. Although this tool was developed for the configuration of AMDREL FPGA reconfigurable platform, it could be used to program any other compatible device. This tool is the only one known academic implementation for FPGA configuration with such features. Among them are the run-time-, partial- and dynamic-reconfiguration, the memory management, the bitstream compression and encryption, the read-back technique, the bitstream reallocation, the used low-power techniques as well as the graphical user interface.

An integrated framework for architecture level exploration of reconfigurable platform

In this paper, the EX-VPR tool, which used for architecture level exploration, is presented. This tool belongs to an integrated framework (MEANDER) for mapping applications into a fine-grain reconfigurable platform (FPGA). Having as input VHDL description of an application, the framework produces the appropriate configuration bitstream. The proposed tool framework supports a variety of FPGA architectures. Additionally, a novel power aware switch box is proposed. Quantitative comparisons with existing switch boxes are provided, yielding promising results.

A memory management approach for efficient implementation of multimedia kernels on programmable architectures

A methodology for power optimization of the data memory hierarchy and instruction memory, is introduced. The impact of the methodology on a set of widely used multimedia application kernels, namely Full Search (FS), Hierarchical Search (HS), Parallel Hierarchical One Dimension Search (PHODS), and Three Step Logarithmic Search (3SLS), is demonstrated. We find the power optimal data memory hierarchy applying the appropriate data-use transformation, while the instruction power optimization is done using suitable cache memory. Using data-reuse transformations, performance optimizations techniques, and instruction-level transformations, we perform exhaustive exploration of an the possible alternatives to reach power efficient solutions. Concerning the embedded processor ARM, the experimental results prove the efficiency of the methodology in terms of power for all the multimedia kernels.

Architecture design of a coarse-grain reconfigurable multiply-accumulate unit for data-intensive applications

A run-time reconfigurable multiply-accumulate (MAC) architecture is introduced. It can be easily reconfigured to trade bitwidth for array size (thus maximizing the utilization of available hardware); process signed-magnitude, unsigned or 2s complement data; make use of part of its structure or adapt its structure based on the specified throughput requirements and the anticipated computational load. The proposed architecture consists of a reconfigurable multiplier, a reconfigurable adder, an accumulation unit, and two units for data representation conversion and incoming and outgoing data stream transfer. Reconfiguration can be done dynamically by using only a few control bits and the main component modules can operate independently from each other. Therefore, they can be enabled or disabled according to the required function each time. Comparison results in terms of performance, area and power consumption prove the superiority of the proposed reconfigurable module over existing realizations in a quantitative and qualitative manner.

A complete platform and toolset for system implementation on fine-grain reconfigurable hardware

In this paper a complete system for the implementation of digital logic in a fine-grain reconfigurable platform is introduced. The system is composed of two parts: the fine-grain reconfigurable hardware platform (FPGA) on which the logic is implemented and the set of CAD tools for mapping logic to the FPGA platform. It is the first such complete academic system. The novel energy efficient FPGA architecture was designed and simulated in STM 0.18 mm CMOS technology. The detailed design and circuit characteristics of the Configurable Logic Block as well as the interconnection network are determined and evaluated for energy, delay and area. Concerning the tool flow, each tool can operate as a standalone program as well as part of a complete design framework, composed by existing and new tools. q 2004 Elsevier B.V. All rights reserved.

An integrated FPGA design framework: custom designed FPGA platform and application mapping toolset development

Summary form only given. A complete system for the implementation of digital logic in a fine-grain reconfigurable platform is introduced. The system is composed of two parts: The fine-grain reconfigurable hardware platform (FPGA) on which the logic is implemented and the set of CAD tools for mapping logic to the FPGA platform. The novel energy-efficient FPGA architecture was designed and simulated in STM 0.18/spl mu/m CMOS technology. Concerning the tool flow, each tool can operate as a standalone program as well as part of a complete design framework, composed by existing and new tools.

A Novel FPGA Architecture and an Integrated Framework of CAD Tools for Implementing Applications

A complete system for the implementation of digital logic in a Field-Programmable Gate Array (FPGA) platform is introduced. The novel power-efficient FPGA architecture was designed and simulated in STM 0.18 μm CMOS technology. The detailed design and circuit characteristics of the Configurable Logic Block, the interconnection network, the switch box and the connection box were determined and evaluated in terms of energy, delay and area. A number of circuit-level low-power techniques were employed because power consumption was the primary concern. Additionally, a complete tool framework for the implementation of digital logic circuits in FPGA platforms is introduced. Having as input VHDL description of an application, the framework derives the reconfiguration bitstream of FPGA. The framework consists of: i) non-modified academic tools, ii) modified academic tools and iii) new tools. Furthermore, the framework can support a variety of FPGA architectures. Qualitative and quantitative comparisons with existing academic and commercial architectures and tools are provided, yielding promising results.

FPGA Architecture Design and Toolset for Logic Implementation

In this paper, the design of an embedded FPGA architecture (i.e. configurable logic blocks) is presented and a complete tool-supported design flow starting from architecture level (i.e. RT-level) and ending with the derivation of the reconfiguration bitstream for the FPGA programming is introduced. The proposed design flow consists of new and modified and extended academic tools. In particular, new tools were developed in order to complement certain critical steps in the implementation flow, since existing academic tools do not combine for a cohesive and complete flow. The remaining design steps are implemented by modified existing academic tools. The FPGA architecture and the tool development is an interactive task, depending on what architectures can be supported by the tools. Using this design support tool set, we designed and simulated in 0.18 TSMC technology an FPGA architecture. More specifically, the detailed design characteristics of the Configurable Logic Block Architecture as well as the interconnect network are determined. Finally, experimental results in terms of energy consumption and delay are given.