1,255 research outputs found
Abstract State Machines 1988-1998: Commented ASM Bibliography
An annotated bibliography of papers which deal with or use Abstract State
Machines (ASMs), as of January 1998.Comment: Also maintained as a BibTeX file at http://www.eecs.umich.edu/gasm
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Behavioral modeling of DRACO : a peripheral interface ASIC
This paper describes the behavioral modeling of DRACO, a peripheral interface Application Specific Integrated Circuit (ASIC) developed by Rockwell International for numerical control applications. The behavioral model was generated from a data sheet of the fabricated chip, which primarily described the chip's input-output functionality, physical and operational characteristics, and a functional block diagram. The data sheet contained very little abstract behavioral information. This report describes the abstract behavioral model of the DRACO chip, and uses flowcharts and VHDL to capture the behavior. The behavioral model was developed through reverse engineering of the data sheet description, supplemented by further consultation with designers of the DRACO ASIC at Rockwell Intemational. The report describes typical behavioral test sequences that were applied to the DRACO VHDL model to verify its correctness. The appendices contain the original DRACO datasheet and the VHDL code used to capture DRACO's behavior
SystemC-based Minimum Intrusive Fault Injection Technique with Improved Fault Representation
In this paper, we propose a new SystemC-based fault injection technique that has improved fault representation in visible and on-the-fly data and signal registers. The technique is minimum intrusive since it only requires replacing the original data or signal types to fault injection enabler types. We compare the proposed simulation technique with recently reported SystemC-based techniques and show that our technique has fast simulation speed, better fault representation, while maintaining simplicity and minimum intrusion. We demonstrate fault injection capabilities in a behavioural SystemC description of MPEG-2 decoder using proposed technique and show that up to 98.9% fault representation within data and signal registers can be achieved
The DS-Pnet modeling formalism for cyber-physical system development
This work presents the DS-Pnet modeling formalism (Dataflow, Signals and Petri nets), designed for the development of cyber-physical systems, combining the characteristics of Petri nets and dataflows to support the modeling of mixed systems containing both reactive parts and data processing operations. Inheriting the features of the parent IOPT Petri net class, including an external interface composed of input and output signals and events, the addition of dataflow operations brings enhanced modeling capabilities to specify mathematical data transformations and graphically express the dependencies between signals. Data-centric systems, that do not require reactive controllers, are designed using pure dataflow models.
Component based model composition enables reusing existing components, create libraries of previously tested components and hierarchically decompose complex systems into smaller sub-systems.
A precise execution semantics was defined, considering the relationship between dataflow and Petri net nodes, providing an abstraction to define the interface between reactive controllers and input and output signals, including analog sensors and actuators.
The new formalism is supported by the IOPT-Flow Web based tool framework, offering tools to design and edit models, simulate model execution on the Web browser, plus model-checking and software/hardware automatic code generation tools to implement controllers running on embedded devices (C,VHDL and JavaScript).
A new communication protocol was created to permit the automatic implementation of distributed cyber-physical systems composed of networks of remote components communicating over the Internet. The editor tool connects directly to remote embedded devices running DS-Pnet models and may import remote components into new models, contributing to simplify the creation of distributed cyber-physical applications, where the communication between distributed components is specified just by drawing arcs.
Several application examples were designed to validate the proposed formalism and the associated framework, ranging from hardware solutions, industrial applications to distributed software applications
Empowering parallel computing with field programmable gate arrays
After more than 30 years, reconïŹgurable computing has grown from a concept to a mature ïŹeld of science and technology. The cornerstone of this evolution is the ïŹeld programmable gate array, a building block enabling the conïŹguration of a custom hardware architecture. The departure from static von Neumannlike architectures opens the way to eliminate the instruction overhead and to optimize the execution speed and power consumption. FPGAs now live in a growing ecosystem of development tools, enabling software programmers to map algorithms directly onto hardware. Applications abound in many directions, including data centers, IoT, AI, image processing and space exploration. The increasing success of FPGAs is largely due to an improved toolchain with solid high-level synthesis support as well as a better integration with processor and memory systems. On the other hand, long compile times and complex design exploration remain areas for improvement. In this paper we address the evolution of FPGAs towards advanced multi-functional accelerators, discuss different programming models and their HLS language implementations, as well as high-performance tuning of FPGAs integrated into a heterogeneous platform. We pinpoint fallacies and pitfalls, and identify opportunities for language enhancements and architectural reïŹnements
CarRing IV- Real-time Computer Network
Ob in der Automobil-, Avionik- oder Automatisierungstechnik, die Fortschritte in der
Echtzeitkommunikation richten sich auf weitere Verbesserungen bereits existierender
Lösungen. Im Kfz-Bereich fĂŒhren die steigenden Zahlen computerbasierter Systeme,
Anwendungen und AnschlĂŒsse sowie die Verwendung mehrerer proprietĂ€rer Kommunikationsstandards zu einem immer komplexeren Kabelbaum. UrsĂ€chlich hierfĂŒr sind
inkompatible Standards, wodurch nicht nur die Kosten, sondern auch das Gewicht
und damit der Kraftstoffverbrauch negativ beeinflusst werden.
Im ersten Teil der Dissertation wird das Echtzeitprotokoll von CarRing IV (CRIV) vorgestellt. Es bietet isochrone und harte Echtzeitgarantien, ohne dass eine netzwerkweite Synchronisation erforderlich ist. Mit bis zu 16 Knoten pro Ring kann
ein CR-IV-Netz aus bis zu 256 Ringen bestehen, die durch Router miteinander verbunden sind. CR-IV verwendet ein reduziertes OSI-Modell (Schichten 1-3, 7), das
fĂŒr seine Anwendungsbereiche sowohl typisch als auch vorteilhaft ist. AuĂerdem
unterstĂŒtzt es sowohl ereignis- als auch zeitgesteuerte Kommunikationsparadigmen.
Der Transparent-Modus ermöglicht es CR-IV, als Backbone fĂŒr bestehende Netze
zu verwenden, wodurch InkompatibilitÀtsprobleme beseitigt werden und der Wechsel zu einer einheitlicheren Netzlösung erleichtert wird. Mit dieser FunktionalitÀt
können NutzergerĂ€te ĂŒber ein CR-IV-Netz miteinander verbunden werden, ohne dass
der Nutzer eingreifen oder etwas Ă€ndern muss. Durch Multicast unterstĂŒtzt CRIV auch die Emulation von Feldbussen. Der zweite Teil der Dissertation stellt den
anderen wichtigen Aspekt von CR-IV vor. Alle Schichten des OSI-Modells sind in
einem FPGA mit Hardware Description Languages (HDLs) ohne Hard- oder Softprozessoren implementiert. Das Register-Transfer-Level (RTL)-Hardwaredesign von
CR-IV wird mit einem neuen Ansatz erstellt, der am besten als tokenbasierter Datenfluss beschrieben werden kann. Der Ansatz ist sowohl vertikal als auch horizontal
skalierbar. Er verwendet lose gekoppelte Processing Elements (PEs), die stateless arbeiten, sowie Arbiter/Speicherzuordnungspaare. Durch die granulare Kontrolle und
die Aufteilung aller Aspekte einer Lösung eignet sich der Ansatz fĂŒr die Implementierung anderer Software-Level-Lösungen in Hardware.
Viele Testszenarios werden durchgefĂŒhrt, um die in CR-IV erzielten Ergebnisse zu
verdeutlichen und zu ĂŒberprĂŒfen. Diese Szenarien reichen von direkten Leistungsmessungen bis hin zu verhaltensspezifischen Tests. ZusĂ€tzlich wird eine Labor-Demo
erstellt, die grundsÀtzlich auf ein Proof of Concept zielt. Die Demo stellt einen
praktischen Test anstelle szenariospezifischer Tests dar. Alle Testszenarien und die
Labor-Demo werden mit den Prototyp-Boards des Projekts durchgefšuhrt, d.h. es sind
keine Simulationstests. Die Ergebnisse stellen die realistischen Leistungen von CR-IV
mit bis zu 13,61 Gbit/s dar.Whether be it automotive, avionics or automation, advances in their respective real-time communication technology focus on further improving preexisting solutions. For
in-vehicle communication, the ever-increasing number of computer-based systems,
applications and connections as well as the use of multiple proprietary communication
standards results in an increasingly complex wiring harness. This is in-part due to
those standards being incompatible with one another. In addition to cost, this also
impacts weight, which in turn affects fuel consumption.
The work presented in this thesis is in-part theoretical and in-part applied. The
former is represented by a new protocol, while the latter corresponds to the protocolâs
hardware implementation. In the first part of the thesis, the real-time communication protocol of CarRing IV (CR-IV) is presented. It provides isochronous and hard
real-time guarantees without requiring network-wide clock synchronization. With up
to 16 nodes per ring, a CR-IV network can consist of as many as 256 rings interconnected by routers. CR-IV uses a reduced OSI model (layers 1-3, 7), which is both
typical of and preferable for its application areas. Moreover, it supports both event- and time-triggered communication paradigms. The transparent mode feature allows
CR-IV to act as a backbone for existing networks, thereby addressing incompatibility
concerns and easing the transition into a more unified network solution. Using this
feature, user devices can communicate with one another via a CR-IV network without
requiring user interference, or any user device or application changes. Combined with
the protocolâs reliable multicast, the feature extends CR-IVâs capabilities to include
field bus emulation. The second part of the thesis presents the other important aspect
of CR-IV. All of its OSI model layers are implemented in a FPGA using Hardware
Description Languages (HDLs) without relying-on or including any hard or soft processors. CR-IVâs Register-Transfer Level (RTL) hardware design is created using a new
approach that can best be described as token-based data-flow. The approach is both
vertically and horizontally scalable. It uses stateless and loosely coupled Processing
Elements (PEs) as well as arbiter/memory allocation pairs. By having granular control and compartmentalizing every aspect of a solution, the approach lends itself to
being used for implementing other software-level solutions in hardware.
Many test scenarios are conducted to both highlight and examine the results
achieved in CR-IV. Those scenarios range from direct performance measurements to
behavior-specific tests. Moreover, a lab-demo is created that essentially amounts to
a proof of concept. The demo represents a practical test as opposed to a scenariospecific one. Whether be it test scenarios or the lab-demo, all are carried-out using the
projectâs prototype boards, i.e. no simulation tests. The results obtained represent
CR-IVâs real-world realistic outcomes with up to 13.61 Gbps
Advanced information processing system: The Army fault tolerant architecture conceptual study. Volume 1: Army fault tolerant architecture overview
Digital computing systems needed for Army programs such as the Computer-Aided Low Altitude Helicopter Flight Program and the Armored Systems Modernization (ASM) vehicles may be characterized by high computational throughput and input/output bandwidth, hard real-time response, high reliability and availability, and maintainability, testability, and producibility requirements. In addition, such a system should be affordable to produce, procure, maintain, and upgrade. To address these needs, the Army Fault Tolerant Architecture (AFTA) is being designed and constructed under a three-year program comprised of a conceptual study, detailed design and fabrication, and demonstration and validation phases. Described here are the results of the conceptual study phase of the AFTA development. Given here is an introduction to the AFTA program, its objectives, and key elements of its technical approach. A format is designed for representing mission requirements in a manner suitable for first order AFTA sizing and analysis, followed by a discussion of the current state of mission requirements acquisition for the targeted Army missions. An overview is given of AFTA's architectural theory of operation
Computer Assisted Design and Integration of FPGA Accelerators in Aerospace Systems
The integration of Field Programmable Gate Arrays (FPGAs) in an aerospace system allows to improve its efficiency and its flexibility thanks to their programmability. To exploit these devices, the designer has to identify the functionalities that have to be executed on them and provide their implementation by means of Hardware Description Languages. Generating these descriptions for a software developer could be a very difficult task because of the different programming paradigms of software programs and hardware descriptions. To facilitate the developer in this activity, High Level Synthesis techniques have been developed aiming at (semi-)automatically generating hardware implementations of specifications written in high level languages (e.g., C). State of the art tools implementing such methodologies have not been designed for the integration with aerospace systems design flows, so significant adaptations could be required to the designer for integrating the hardware implementations with the rest of the design solution.
In this paper the integration of a High Level Synthesis design flow in the TASTE framework (http://taste.tuxfamily.org) is presented. TASTE is a set of freely available tools for the development of real time embedded systems developed by the European Space Agency together with a set of its industrial partners. This framework allows to integrate specifications described in different languages (e.g., C, ADA, Simulink, SDL) by means of formal languages (AADL and ASN.1) and to early verify the correctness of the produced solutions. TASTE has been extended with Bambu (http://panda.dei.polimi.it), a tool for the High Level Synthesis developed at Politecnico di Milano. In this way the TASTE users have the possibility to specify which functionalities, provided by means of high level languages such C, have to be implemented in hardware on the FPGA without having to directly provide the hardware implementations. Thanks to the integration of the High Level Synthesis tool indeed, the framework is able not only to produce the hardware implementations, but also to integrate them in the rest of the aerospace system by automatically generating the whole architecture to be implemented on the FPGA. This architecture contains not only the implementation of the hardware accelerators, but also of the components required to transfer the data from and to the rest of the system and to correctly manage their size and endianness.
The application of the extended framework to a real case study shows its effective usability
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