1,516 research outputs found
A multi-paradigm language for reactive synthesis
This paper proposes a language for describing reactive synthesis problems
that integrates imperative and declarative elements. The semantics is defined
in terms of two-player turn-based infinite games with full information.
Currently, synthesis tools accept linear temporal logic (LTL) as input, but
this description is less structured and does not facilitate the expression of
sequential constraints. This motivates the use of a structured programming
language to specify synthesis problems. Transition systems and guarded commands
serve as imperative constructs, expressed in a syntax based on that of the
modeling language Promela. The syntax allows defining which player controls
data and control flow, and separating a program into assumptions and
guarantees. These notions are necessary for input to game solvers. The
integration of imperative and declarative paradigms allows using the paradigm
that is most appropriate for expressing each requirement. The declarative part
is expressed in the LTL fragment of generalized reactivity(1), which admits
efficient synthesis algorithms, extended with past LTL. The implementation
translates Promela to input for the Slugs synthesizer and is written in Python.
The AMBA AHB bus case study is revisited and synthesized efficiently,
identifying the need to reorder binary decision diagrams during strategy
construction, in order to prevent the exponential blowup observed in previous
work.Comment: In Proceedings SYNT 2015, arXiv:1602.0078
Testing micropipelines
Journal ArticleMicropipelines, self-timed event-driven pipelines, are an attractive way of structuring asynchronous systems that exhibit many of the advantages of general asynchronous systems, but enough structure to make the design of significant systems practical. As with any design method, testing is critical. We present a technique for testing self-timed micropipelines for stuck-at faults and for delay faults an the bundled data paths by modifying the latch and control elements to include a built-in scan path for testing. This scan path allows the processing logic in the micropipeline, to be fully tested with only a small overhead in the latch and control circuits. The test method is very similar to scan testing in synchronous systems, but the micropipeline retains its self-timed behavior during normal operation
Testing self-timed circuits using partial scan
Journal ArticleThis paper presents a partial scan method for testing both the control and data path parts of macromodule based self-timed circuits for stuck-at faults. Compared with other proposed test methods for testing control paths in self-timed circuits, this technique offers better fault coverage under a stuck-at input model than methods using self-checking properties, and requires fewer storage elements to be made scanable than full scan approaches with similar fault coverage. A new method is proposed to test the sequential network in the control path in this partial scan environment. The partial scan approach has also been applied to datapaths, where structural analysis is used to select which latches should be made scannable to break cycles in the circuit. Experimental data is presented to show that high fault coverage is possible using this method with only a subset of storage elements in the control and data paths being made scannable
Design Optimization Of Datapath Transmitter In Bluetooth Baseband Controller
A Bluetooth baseband controller is placed in the physical layer of the Bluetooth Protocol stack to manage all the physical channels and links like error correction, hop selection, security and data whitening. The baseband handles the packets and does the inquiry for the Bluetooth devices in the area. The optimization of the performance is needed but it is of a trade off with the area and power consumption of the device. The bigger the design, the more the power being consumed. In this thesis, the objective is to optimize the design of the transmitter in the datapath of the Bluetooth baseband controller. It is also part of the objective to improve the RC delay of the worst path timing. The inherited codes need to be verified with a test bench on Model Sim first. Then, a synthesis process is being done using the Synopsys tool in order to generate a netlist. The netlist is then being translated into physical implementation of the logic and the layout is formed. Then, the optimization process starts again from the VHDL code to the layout process. The synthesized results are first being compared with the results from the IC Compiler. The results of the synthesized results before and after optimization is being compared as well. It is shown that the optimized design has a larger area and power consumption of 75023.627147 square micron and 18.2595 mW but the timing in the worst path is significantly improved from 4 ps to 390 ps. The transmitter is able to operate at 200 MHz from the constraint set and the operating voltage is at 1.62 V. Thus, a tradeoff with the area and power consumption is in place if optimization on the timing performance is done. The focus of this project is on the performance of the design
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
A partial scan methodology for testing self-timed circuits
technical reportThis paper presents a partial scan method for testing control sections of macromodule based self-timed circuits for stuck-at faults. In comparison with other proposed test methods for self-timed circuits, this technique offers better fault coverage than methods using self-checking techniques, and requires fewer storage elements to be made scannable than full scan approaches with similar fault coverage. A new method is proposed to test the sequential network in this partial scan environment. Experimental data is presented to show that high fault coverage is possible using this method with only a subset of storage elements being made scannable
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