14 research outputs found

    Structured ASIC, evolution or revolution?

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    INTEND OF LUT/MUX COMPLEXS BY USING FPGA MODUS OPERANDI

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    For reducing the area and improving the performance of logical circuits, a combination of Lookup Table (LUT) with multiplexer methodology is applied together. By implementing this kind of architecture a new MUX: LUT structure is designed, which works based on the number of comparators and logical circuits. This implementation is more suitable for both accounting for complex logic block and routing area while maintaining mapping depth. Interconnections are increasingly the dominant contributor to delay, area and energy consumption in Complementary Metal-Oxide Semiconductor (CMOS) digital circuits. The proposed implementation overcomes several limitations found in previous quaternary implementations published so far, such as the need for special features in the CMOS process or power-hungry current-mode cells. We have to use the 512bit quaternary Lookup Table for a high level of operations in the FPGA. The proposed architecture of this paper will be planned to implemented and also analysis the output current, output voltage, area using Xilinx 14.3

    Programmable flexible cores for SoC applications

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    Tese de mestrado. Engenharia Electrotécnica e de Computadores. Faculdade de Engenharia. Universidade do Porto. 200

    Desenvolvimento de um sistema para auxílio à locomoção de deficientes visuais através da implementação em arquiteturas reconfiguráveis da transformada Census para estimação de distância usando visão estéreo

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    Monografia (graduação)—Universidade de Brasília, Faculdade UnB Gama, 2013.Este trabalho propõe um sistema de auxílio para deficientes visuais no intuito de aumentar a independência e gerar uma melhor qualidade de vida. O sistema está baseado no cálculo de correspondências e disparidades entre duas imagens estereoscópicas, para o qual foi usada a transformada Census e o cálculo da distância de Hamming visando estimar a distância frontal até os obstáculos. O sistema proposto está composto por um par de câmeras e um dispositivo FPGA (Field Programmable Gate Array) que acelera a execução dos algoritmos envolvidos. Uma ferramenta de geração automática de código VHDL foi construída no intuito de acelerar o tempo de desenvolvimento da implementação das arquiteturas de hardware para diferentes tamanhos de imagem usando máscaras de 3x3, 5x5, 7x7, 9x9 e 11x11 pixels. Todas as arquiteturas foram sintetizadas e um estudo de escalabilidade em termos de consumo de recursos foi realizado. Os resultados de síntese demonstram que as arquiteturas de hardware são eficientemente mapeadas em dispositivos FPGA comerciais, alcançando uma frequência de operação de 180MHz aproximadamente. Duas memorias ROM, uma para cada imagem, foram instanciadas visando emular o fluxo de pixels das câmeras esquerda e direita, e simulações comportamentais foram realizadas no intuito de verificar o comportamento lógico das arquiteturas. A mesma técnica foi implementada em hardware e software e a comparação numérica entre as implementações demonstram a eficiência das arquiteturas propostas, além disso, é possível concluir que as arquiteturas propostas apresentam resultados eficientes em termos da qualidade do mapa de disparidade. Um fator de aceleração de 211 vezes foi alcançado para o cálculo do mapa de disparidade se comparado com uma implementação em software usando um Desktop convencional Intel Core i7 operando a 3.4 GHz. É importante ressaltar que a utilização da transformada Census básica acrescenta ruído no processo de cálculo de correspondência entre as imagens e que a utilização das transformadas modificadas melhoram a performance dos resultados.This work proposes a system to help visually impaired people in order to improve their independence and quality of life. The system is based on the disparity map computation between two stereoscopic images and uses the Census transform and the Hamming distance for estimating the distance between the system and the obstacles. The proposed system is composed of a stereoscopic system and a FPGA (Field Programmable Gate Array) which accelerates the execution time of the involved algorithms. In this work a VHDL code generator was created for implementing the hardware architectures for different images sizes and mask sizes of 3x3, 5x5, 7x7 and 9x9 pixels. All the hardware architectures were synthesized and a scalability analysis in terms of hardware resources consumption was provided. Synthesis results demonstrates that the hardware architectures are efficiently mapped on commercial FPGA devices, achieving an operational frequency of 180MHz approximately. Two ROM memories, one for each image, were instantiated in order to emulate the stream of pixels from the left and right cameras and behavioural simulations were performed in order to verify the logic implementation of the architectures. Numerical comparisons between hardware and software implementations demonstrated the effectiveness of the proposed architectures. A speed up factor of 211 times was achieved for computing the disparity map between two images if compared with a software implementation using a Desktop solution Intel Core i7 operating at 3.4 GHz

    Digital Circuit Design Using Floating Gate Transistors

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    Floating gate (flash) transistors are used exclusively for memory applications today. These applications include SD cards of various form factors, USB flash drives and SSDs. In this thesis, we explore the use of flash transistors to implement digital logic circuits. Since the threshold voltage of flash transistors can be modified at a fine granularity during programming, several advantages are obtained by our flash-based digital circuit design approach. For one, speed binning at the factory can be controlled with precision. Secondly, an IC can be re-programmed in the field, to negate effects such as aging, which has been a significant problem in recent times, particularly for mission-critical applications. Thirdly, unlike a regular MOSFET, which has one threshold voltage level, a flash transistor can have multiple threshold voltage levels. The benefit of having multiple threshold voltage levels in a flash transistor is that it allows the ability to encode more symbols in each device, unlike a regular MOSFET. This allows us to implement multi-valued logic functions natively. In this thesis, we evaluate different flash-based digital circuit design approaches and compare their performance with a traditional CMOS standard cell-based design approach. We begin by evaluating our design approach at the cell level to optimize the design’s delay, power energy and physical area characteristics. The flash-based approach is demonstrated to be better than the CMOS standard cell approach, for these performance metrics. Afterwards, we present the performance of our design approach at the block level. We describe a synthesis flow to decompose a circuit block into a network of interconnected flash-based circuit cells. We also describe techniques to optimize the resulting network of flash-based circuit cells using don’t cares. Our optimization approach distinguishes itself from other optimization techniques that use don’t cares, since it a) targets a flash-based design flow, b) optimizes clusters of logic nodes at once instead of one node at a time, c) attempts to reduce the number of cubes instead of reducing the number of literals in each cube and d) performs optimization on the post-technology mapped netlist which results in a direct improvement in result quality, as compared to pre-technology mapping logic optimization that is typically done in the literature. The resulting network characteristics (delay, power, energy and physical area) are presented. These results are compared with a standard cell-based realization of the same block (obtained using commercial tools) and we demonstrate significant improvements in all the design metrics. We also study flash-based FPGA designs (both static and dynamic), and present the tradeoff of delay, power dissipation and energy consumption of the various designs. Our work differs from previously proposed flash-based FPGAs, since we embed the flash transistors (which store the configuration bits) directly within the logic and interconnect fabrics. We also present a detailed description of how the programming of the configuration bits is accomplished, for all the proposed designs

    Digital Circuit Design Using Floating Gate Transistors

    Get PDF
    Floating gate (flash) transistors are used exclusively for memory applications today. These applications include SD cards of various form factors, USB flash drives and SSDs. In this thesis, we explore the use of flash transistors to implement digital logic circuits. Since the threshold voltage of flash transistors can be modified at a fine granularity during programming, several advantages are obtained by our flash-based digital circuit design approach. For one, speed binning at the factory can be controlled with precision. Secondly, an IC can be re-programmed in the field, to negate effects such as aging, which has been a significant problem in recent times, particularly for mission-critical applications. Thirdly, unlike a regular MOSFET, which has one threshold voltage level, a flash transistor can have multiple threshold voltage levels. The benefit of having multiple threshold voltage levels in a flash transistor is that it allows the ability to encode more symbols in each device, unlike a regular MOSFET. This allows us to implement multi-valued logic functions natively. In this thesis, we evaluate different flash-based digital circuit design approaches and compare their performance with a traditional CMOS standard cell-based design approach. We begin by evaluating our design approach at the cell level to optimize the design’s delay, power energy and physical area characteristics. The flash-based approach is demonstrated to be better than the CMOS standard cell approach, for these performance metrics. Afterwards, we present the performance of our design approach at the block level. We describe a synthesis flow to decompose a circuit block into a network of interconnected flash-based circuit cells. We also describe techniques to optimize the resulting network of flash-based circuit cells using don’t cares. Our optimization approach distinguishes itself from other optimization techniques that use don’t cares, since it a) targets a flash-based design flow, b) optimizes clusters of logic nodes at once instead of one node at a time, c) attempts to reduce the number of cubes instead of reducing the number of literals in each cube and d) performs optimization on the post-technology mapped netlist which results in a direct improvement in result quality, as compared to pre-technology mapping logic optimization that is typically done in the literature. The resulting network characteristics (delay, power, energy and physical area) are presented. These results are compared with a standard cell-based realization of the same block (obtained using commercial tools) and we demonstrate significant improvements in all the design metrics. We also study flash-based FPGA designs (both static and dynamic), and present the tradeoff of delay, power dissipation and energy consumption of the various designs. Our work differs from previously proposed flash-based FPGAs, since we embed the flash transistors (which store the configuration bits) directly within the logic and interconnect fabrics. We also present a detailed description of how the programming of the configuration bits is accomplished, for all the proposed designs
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