391 research outputs found
User microprogrammable processors for high data rate telemetry preprocessing
The use of microprogrammable processors for the preprocessing of high data rate satellite telemetry is investigated. The following topics are discussed along with supporting studies: (1) evaluation of commercial microprogrammable minicomputers for telemetry preprocessing tasks; (2) microinstruction sets for telemetry preprocessing; and (3) the use of multiple minicomputers to achieve high data processing. The simulation of small microprogrammed processors is discussed along with examples of microprogrammed processors
A heterogeneous computer vision architecture: implementation issues
The prototype of a heterogeneous architecture is currently being built. The architecture is aimed at video-rate computing and is based on a message passing MIMD topology at the top level-transputer based-and on VLSI associative processor arrays (APA, SIMD structure) for low level image processing tasks. The APA structure is implemented through a set of 4 VLSI chips (GLiTCH) containing 64 1-bit processing elements each. This communication addresses some issues concerning the implementation of the first prototype, namely those related to:
• the design and integration of the APA controller unit, which provides the required interface between the APA, the MIMD topology and the video image interface:
• the evaluation of the GLiTCH chip through an emulator based on transputers and fast programmable devices; the emulator was designed to be flexible enough to evaluate later modifications to the GLiTCH design;
• the design of an integrated set of software development tools containing a structured editor-syntax oriented, with a visual interface/programming interface-and a cross compiler and debugger
Fault-tolerant computer study
A set of building block circuits is described which can be used with commercially available microprocessors and memories to implement fault tolerant distributed computer systems. Each building block circuit is intended for VLSI implementation as a single chip. Several building blocks and associated processor and memory chips form a self checking computer module with self contained input output and interfaces to redundant communications buses. Fault tolerance is achieved by connecting self checking computer modules into a redundant network in which backup buses and computer modules are provided to circumvent failures. The requirements and design methodology which led to the definition of the building block circuits are discussed
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Behavioral synthesis from VHDL using structured modeling
This dissertation describes work in behavioral synthesis involving the development of a VHDL Synthesis System VSS which accepts a VHDL behavioral input specification and performs technology independent synthesis to generate a circuit netlist of generic components. The VHDL language is used for input and output descriptions. An intermediate representation which incorporates signal typing and component attributes simplifies compilation and facilitates design optimization.A Structured Modeling methodology has been developed to suggest standard VHDL modeling practices for synthesis. Structured modeling provides recommendations for the use of available VHDL description styles so that optimal designs will be synthesized.A design composed of generic components is synthesized from the input description through a process of Graph Compilation, Graph Criticism, and Design Compilation. Experiments were performed to demonstrate the effects of different modeling styles on the quality of the design produced by VSS. Several alternative VHDL models were examined for each benchmark, illustrating the improvements in design quality achieved when Structured Modeling guidelines were followed
Concepts for on-board satellite image registration. Volume 3: Impact of VLSI/VHSIC on satellite on-board signal processing
Anticipated major advances in integrated circuit technology in the near future are described as well as their impact on satellite onboard signal processing systems. Dramatic improvements in chip density, speed, power consumption, and system reliability are expected from very large scale integration. Improvements are expected from very large scale integration enable more intelligence to be placed on remote sensing platforms in space, meeting the goals of NASA's information adaptive system concept, a major component of the NASA End-to-End Data System program. A forecast of VLSI technological advances is presented, including a description of the Defense Department's very high speed integrated circuit program, a seven-year research and development effort
Fault-tolerant building-block computer study
Ultra-reliable core computers are required for improving the reliability of complex military systems. Such computers can provide reliable fault diagnosis, failure circumvention, and, in some cases serve as an automated repairman for their host systems. A small set of building-block circuits which can be implemented as single very large integration devices, and which can be used with off-the-shelf microprocessors and memories to build self checking computer modules (SCCM) is described. Each SCCM is a microcomputer which is capable of detecting its own faults during normal operation and is described to communicate with other identical modules over one or more Mil Standard 1553A buses. Several SCCMs can be connected into a network with backup spares to provide fault-tolerant operation, i.e. automated recovery from faults. Alternative fault-tolerant SCCM configurations are discussed along with the cost and reliability associated with their implementation
Techniques for the realization of ultrareliable spaceborne computers Interim scientific report
Error-free ultrareliable spaceborne computer
HAL-ASOS - Linux com aceleração em hardware para sistemas operativos dedicados à aplicação
Programa doutoral em Engenharia Eletrónica e de Computadores (PDEEC) (especialidade de Informática Industrial e Sistemas Embebidos)O ecossistema de sistemas embebidos de hoje tornou-se enorme, cobrindo vários e diferentes sistemas,
exigindo desempenho e mobilidade completa enquanto atingem autonomias de bateria cada vez maiores.
Mas a crescente frequência de relógio que resultou em dispositivos cada vez mais rápidos começou a
estagnar antes dos transístores pararem de encolher. Plataformas Field Programmable Gate Array (FPGA)
são uma solução alternativa para a implementação de sistemas completos e reconfiguráveis. Fornecem
desempenho e eficiência computacional para satisfazer requisitos da aplicação e do sistema embebido.
Vários Sistemas Operativos (SO) assistidos por FPGA foram propostos, mas ao estreitar seu foco na síntese
do datapath do acelerador de hardware, a grande maioria ignora a integração semântica destes no
SO. Ambientes de síntese de alto nível (HLS) elevaram a abstração além da linguagem de transferência de
registo (RTL), seguindo uma abordagem específica de domínio enquanto misturam software e abstrações
de hardware ad hoc, que dificultam as otimizações. Além disso, os modelos de programação para software
e hardware reconfigurável carecem de semelhanças, o que com o tempo dificultará a Exploração
do Ambiente de Design (DSE) e diminuirá o potencial de reutilização de código. Para responder a estas
necessidades, propomos HAL-ASOS, uma ferramenta para implementar sistemas embebidos baseados
em Linux que fornece (1) elasticidade no design em conformidade com a natureza evolutiva deste SO, (2)
integração semântica profunda de tarefas de hardware nos modelos de programação do Linux, (3) facilidade
na gestão de complexidade através de metodologia e ferramentas para apoiar o design, verificação
e implementação, (4) orientada por princípios de design híbridos e eficiência no sistema. Para avaliar as
funcionalidades da ferramenta, foi implementado um aplicativo criptográfico que demonstra alcance de
desempenho enquanto se emprega a metodologia de design. Novos níveis de desempenho são atingidos
numa aplicação de Visão por Computador que explora recursos de programação assíncrona-síncrona. Os
resultados demonstram uma abordagem flexível na reconfiguração entre hardware e software, e desempenho
que aumenta consistentemente com acréscimo de recursos ou frequência de relógio.Today’s embedded systems ecosystem became huge while covering several and different computer-based
systems, demanding for performance and complete mobility while experiencing longer battery lives. But
the rampant frequency that resulted in faster devices began hitting a wall even before transistors stopped
shrinking. Field Programmable Gate Array (FPGA) platforms are an alternative solution towards implementing
complete reconfigurable systems. They provide computational power, efficiency, in a lightweight
solution to serve the application requirements and increase performance in the overall system. Several
FPGA-assisted Operating Systems (OS) have been proposed, but by narrowing their focus on datapath
synthesis of the hardware accelerator, they completely ignore the deep semantic integration of these accelerators
into the OS. State-of-the-art High-Level Synthesis (HLS) environments have raised the level of
abstraction beyond Register Transfer Language (RTL) by following a domain-specific approach while mixing
ad hoc software and hardware abstractions, making harder for performance optimizations. Furthermore,
the programming models for software and reconfigurable hardware lack commonalities, which in time will
hinder the Design Space Exploration (DSE) and lower the potential for code reuse. To overcome these
issues, we propose HAL-ASOS, a framework to implement Linux-based Embedded systems which provides
(1) elasticity by design to comply with the evolutive nature of Linux, (2) deep semantic integration of the
hardware tasks in the Linux programming models, (3) easy complexity management using methodology
and tools to fully support design, verification and deployment, (4) hybrid and efficiency-oriented design
principles. To evaluate the framework functionalities, a cryptographic application was implemented and
demonstrates performance achievements while using the promoted application-driven design methodology.
To demonstrate new levels of performance that can be achieved, a Computer Vision application
explores several mixed asynchronous-synchronous programming features. Experiments demonstrate a
flexible design approach in terms of hardware and software reconfiguration, and significant performance
that increases consistently with the rising in processing resources or clock frequencies.Financial support received from Portuguese Foundation for Science and Technology (FCT) with the PhD grant SFRH/BD/82732/2011
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