Sistemas embarcados baseados em processadores têm sido largamente aplicados em áreas críticas no que diz respeito à segurança de seres humanos e do meio ambiente. Em tais aplicações, que compreendem desde o controle de freio de carros a missões espaciais, pode ser necessária a execução confiável de todas as funcionalidades do sistema durante longos períodos e em ambientes desconhecidos, hostis ou instáveis. Mesmo em aplicações não críticas, nas quais a confiabilidade do sistema não é um requisito primordial, o usuário final deseja que seu produto apresente comportamento estável e livre de erros. Daí vem a importância de se considerar o auto-teste on-line no projeto dos sistemas embarcados atuais. Entretanto, a crescente complexidade de tais sistemas somada às fortes restrições a que eles estão sujeitos torna o projeto do auto-teste um problema cada vez mais desafiador. Em aplicações de tempo-real a dificuldade é ainda maior, uma vez que, além dos cuidados com as restrições do sistema alvo, deve-se levar em conta o atendimento dos requisitos temporais da aplicação. Entre as técnicas de auto-teste on-line atualmente pesquisadas, uma tem se destacado pela eficácia obtida a um baixo custo de projeto e sem grande impacto no atendimento dos requisitos e restrições do sistema: o auto-teste baseado em software (SBST – Software-Based Self-Test). Neste trabalho, é proposta uma metodologia para o projeto e aplicação de auto-teste on-line para processadores embarcados, considerando-se também aplicações de temporeal. Tal metodologia, denominada STEP (Self-Test for Embedded Processors), tem como base a técnica SBST e prevê o planejamento, a geração e a seleção de rotinas de teste para o processador alvo. O método proposto garante a execução periódica do autoteste, com o menor período permitido pela aplicação de tempo-real, e assegura o atendimento de todas as restrições do sistema embarcado. Além disso, a solução fornecida pelo método alcança uma boa qualidade de teste enquanto auxilia a redução de custos do sistema final. Como estudo de caso, a metodologia proposta é aplicada a diferentes arquiteturas de processadores Java e os resultados obtidos comprovam a eficiência da mesma. Por fim, é apresentada uma ferramenta que implementa a metodologia STEP, automatizando, assim, o projeto e a aplicação de auto-teste on-line para os processadores estudados. / Processor-based embedded systems have been widely used in safety-critical applications. In such applications, which include from cars break control to spatial missions, the whole system operation must be reliable during long periods even within unknown, hostile and unstable environments. In non-critical applications, system reliability is not a prime requirement, but the final user requires an error free product, with stable behavior. Hence, one can realize the importance of on-line self-testing in current embedded systems. Self-testing is becoming an important challenge due to the increasing complexity of the systems allied to their strong constraints. In real-time applications this problem becomes even more complex, since, besides meeting systems constraints, one must take into consideration the application timing requirements. Among all on-line self-testing techniques studied, Software-Based Self-Test (SBST) has been distinguished by its effectiveness, low-cost and small impact on system constraints and requirements. This work proposes a methodology for the design and implementation of on-line self-test in embedded processors, considering real-time applications. Such a methodology, called STEP (Self-Test for Embedded Processors), is based on SBST technique and encloses planning, generation and selection of test routines for the target processor. The proposed method guarantees periodical self-test execution, at the smallest period allowed by the real-time application, and ensures that all embedded system constraints are met. Furthermore, provided solution achieves high test quality while helping in the optimization of the costs of the final system. The proposed methodology is applied to different architectures of Java processors to demonstrate its efficiency. Finally, this work presents a tool that automates the design and implementation of on-line self-test in the studied processors by implementing the STEP methodology.

Sistemas embarcados baseados em processadores têm sido largamente aplicados em áreas críticas no que diz respeito à segurança de seres humanos e do meio ambiente. Em tais aplicações, que compreendem desde o controle de freio de carros a missões espaciais, pode ser necessária a execução confiável de todas as funcionalidades do sistema durante longos períodos e em ambientes desconhecidos, hostis ou instáveis. Mesmo em aplicações não críticas, nas quais a confiabilidade do sistema não é um requisito primordial, o usuário final deseja que seu produto apresente comportamento estável e livre de erros. Daí vem a importância de se considerar o auto-teste on-line no projeto dos sistemas embarcados atuais. Entretanto, a crescente complexidade de tais sistemas somada às fortes restrições a que eles estão sujeitos torna o projeto do auto-teste um problema cada vez mais desafiador. Em aplicações de tempo-real a dificuldade é ainda maior, uma vez que, além dos cuidados com as restrições do sistema alvo, deve-se levar em conta o atendimento dos requisitos temporais da aplicação. Entre as técnicas de auto-teste on-line atualmente pesquisadas, uma tem se destacado pela eficácia obtida a um baixo custo de projeto e sem grande impacto no atendimento dos requisitos e restrições do sistema: o auto-teste baseado em software (SBST – Software-Based Self-Test). Neste trabalho, é proposta uma metodologia para o projeto e aplicação de auto-teste on-line para processadores embarcados, considerando-se também aplicações de temporeal. Tal metodologia, denominada STEP (Self-Test for Embedded Processors), tem como base a técnica SBST e prevê o planejamento, a geração e a seleção de rotinas de teste para o processador alvo. O método proposto garante a execução periódica do autoteste, com o menor período permitido pela aplicação de tempo-real, e assegura o atendimento de todas as restrições do sistema embarcado. Além disso, a solução fornecida pelo método alcança uma boa qualidade de teste enquanto auxilia a redução de custos do sistema final. Como estudo de caso, a metodologia proposta é aplicada a diferentes arquiteturas de processadores Java e os resultados obtidos comprovam a eficiência da mesma. Por fim, é apresentada uma ferramenta que implementa a metodologia STEP, automatizando, assim, o projeto e a aplicação de auto-teste on-line para os processadores estudados. / Processor-based embedded systems have been widely used in safety-critical applications. In such applications, which include from cars break control to spatial missions, the whole system operation must be reliable during long periods even within unknown, hostile and unstable environments. In non-critical applications, system reliability is not a prime requirement, but the final user requires an error free product, with stable behavior. Hence, one can realize the importance of on-line self-testing in current embedded systems. Self-testing is becoming an important challenge due to the increasing complexity of the systems allied to their strong constraints. In real-time applications this problem becomes even more complex, since, besides meeting systems constraints, one must take into consideration the application timing requirements. Among all on-line self-testing techniques studied, Software-Based Self-Test (SBST) has been distinguished by its effectiveness, low-cost and small impact on system constraints and requirements. This work proposes a methodology for the design and implementation of on-line self-test in embedded processors, considering real-time applications. Such a methodology, called STEP (Self-Test for Embedded Processors), is based on SBST technique and encloses planning, generation and selection of test routines for the target processor. The proposed method guarantees periodical self-test execution, at the smallest period allowed by the real-time application, and ensures that all embedded system constraints are met. Furthermore, provided solution achieves high test quality while helping in the optimization of the costs of the final system. The proposed methodology is applied to different architectures of Java processors to demonstrate its efficiency. Finally, this work presents a tool that automates the design and implementation of on-line self-test in the studied processors by implementing the STEP methodology.

Master of Science / Department of Electrical Engineering / William Kuhn / When enough charges accumulate on two objects, the air dielectric between them breaks down to create a phenomenon known as electrostatic discharge (ESD). ESD is of great concern in the integrated circuit industry because of the damage it can cause to ICs. The problem will only become worse as process components become smaller. The three main types of ESD experienced by an IC are the human body model (HBM), the charged device model (CDM), and the machine model (MM). HBM ESD has the highest voltage while CDM ESD has the highest bandwidth and current of the three ESD types. Integrated circuits generally include ESD protection circuitry connected to their pads. Pads are the connection between the IC and the outside world, making them the required location for circuitry designed to route ESD events away from the IC's internal circuitry. The most basic protection pads use diodes connected from I/O to VDD and I/O to ground. A voltage clamp between VDD and ground is also necessary to protect against CDM and MM event types where the device may not yet have a low impedance supply path connected. The purpose of this research is to investigate the performance of ESD circuits and to develop a method for detecting the occurrence of an ESD event in an integrated circuit by utilizing IC fuses. The combination of IC fuses and detection circuitry designed to sense a broken fuse allows the IC to perform a built-in self-test (BIST) for ESD to identify compromised ICs, preventing manufacturers from shipping damaged circuits. Simulations are used to design an optimized protection circuit to complement the proposed ESD detection circuit. Optimization of an ESD pad circuit increases the turn-on speed of its voltage clamps and decreases the series resistance of its protection diodes. These improvements minimize the stress voltage placed on internal circuitry due to an ESD event. An ESD measurement setup is established and used to verify voltage clamp operation. This research also proposes an ESD detection circuit based on IC fuses, which fail during an ESD event. A variety of IC fuses are tested using the ESD measurement setup as well as a TLP setup in order to determine the time and current needed for them to break. Suitable IC fuses have a resistance less than 5 Ω and consistently break during the first trial.

<p>The technological development is enabling production of increasingly complex electronic systems. All those systems must be verified and tested to guarantee correct behavior. As the complexity grows, testing is becoming one of the most significant factors that contribute to the final product cost. The established low-level methods for hardware testing are not any more sufficient and more work has to be done at abstraction levels higher than the classical gate and register-transfer levels. This thesis reports on one such work that deals in particular with high-level test generation and design for testability techniques.</p><p>The contribution of this thesis is twofold. First, we investigate the possibilities of generating test vectors at the early stages of the design cycle, starting directly from the behavioral description and with limited knowledge about the final implementation architecture. We have developed for this purpose a novel hierarchical test generation algorithm and demonstrated the usefulness of the generated tests not only for manufacturing test but also for testability analysis.</p><p>The second part of the thesis concentrates on design for testability. As testing of modern complex electronic systems is a very expensive procedure, special structures for simplifying this process can be inserted into the system during the design phase. We have proposed for this purpose a novel hybrid built-in self-test architecture, which makes use of both pseudorandom and deterministic test patterns, and is appropriate for modern system-on-chip designs. We have also developed methods for optimizing hybrid built-in self-test solutions and demonstrated the feasibility and efficiency of the proposed technique.</p> / Report code: LiU-Tek-Lic-2002:46.

<p>The rapid progress made in integrating enormous numbers of transistors on a single chip is making it possible for hardware designers to implement more complex hardware architectures in their designs. Nowadays digital telecommunication systems are implementing several forms of SOC (System-On-Chip) structures. These SOCs usually contain a microprocessor, several DSP cores (Digital-Signal-Processors), other hardware blocks, on-chip memories and peripherals.</p><p>As new IC process technologies are deployed, with decreasing geometrical dimensions, the probabilities of hardware faults to occur during operation are increasing. Testing SOCs is becoming a very complex issue due to the increasing complexity of the design and the increasing need of a test mechanism that is able to achieve acceptable fault coverage in a short test application time with low power consumption without the use of external logic testers.</p><p>As a part of the overall test strategy for a SOC, functional self-testing of a DSP core is considered in this project to be applied in the field. This test is used to verify whether fault indications in systems are caused by permanent hardware faults in the DSP. If so, the DSP where the fault is located needs to be taken out of operation, and the board it sits on will be later replaced. If not, the operational state can be restored, and the system will become fully functional again.</p><p>The main purpose of this project is to develop a functional self-test of a DSP core, and to evaluate the characteristics of the test. This project also involves proposing a scheme on how to apply a functional test on a DSP core in an embedded environment, and how to retrieve results from the test. The test program shall run at system speed.</p><p>To develop and measure the quality of the test program, two different coverage metrics were used. The first is the code coverage metric achieved by simulating the test program on the RTL representation of the DSP. The second metric used was the fault coverage achieved. The fault coverage of the test was calculated using a commercial Fault Simulator working on a gate-level representation of the DSP. The results achieved in this report show that this proposed approach can achieve acceptable levels of fault coverage in short execution time without the need for external testers which makes it possible to perform the self-test in the field. This approach has the unique property of not requiring any hardware modifications in the DSP design, and the ability of testing several DSPs in parallel.</p>

Thesis (M.S.)--Auburn University, 2008. / Abstract. Vita. Includes bibliographical references (p. 104-106).

Thesis(M.S.)--Auburn University, 2004. / Abstract. Vita. Includes bibliographic references (p.123-125).

Thesis--Auburn University, 2009. / Abstract. Vita. Includes bibliographical references (p. 112-113).

Nürnberg, University, Diss., 2004--Erlangen.

Cette thèse vise l’étude de nouvelles architectures d’auto test pour les convertisseurs de type pipeline. En production, les convertisseurs sont testés en fonctionnement statique et dynamique. Les techniques de test statique de linéarité sont les techniques les plus coûteuses durant la phase de production. La mesure des performances statiques utilise un stimulus à haute linéarité et très basse fréquence et la méthode de l’histogramme, nécessitant la collecte d’un grand nombre d’échantillons en sortie afin de moyenner le bruit. Ainsi, la quantité de données nécessaire augmente exponentiellement avec la résolution du CAN sous test. Pour cette raison, la réduction du temps de test des CANs est un domaine de recherche qui attire de plus en plus d’attention. Récemment, des nouvelles solutions ont été mises au point pour réduire de façon importante le temps de test, mais aucune solution d’auto test considérant un générateur de signal de haute résolution en combinaison avec une technique d'analyse intégrée, réduisant considérablement la quantité de données, n’a encore été développée. Dans le cadre de cette thèse, on envisage l’étude de techniques d’auto test statique pour ce type de convertisseurs. En particulier, cette thèse présente un générateur de stimulus de test intégré à haute linéarité et une technique modifiée de servo-loop qui, en combinaison avec un algorithme de test de linéarité avec réduction de codes, conduit à la définition d'une stratégie efficace et précise de test intégré pour les CANs de type pipeline. La thèse inclut la validation expérimentale des techniques proposées, en coopération avec ST Microelectronics, Grenoble. / This PhD thesis is aimed at exploring new Built-In-Self-Test (BIST) techniques for static linearity characterization of pipeline ADCs. During the production phase, the static and dynamic performances of the ADCs are tested. Static linearity test techniques are one of the more expensive test procedures that are performed at production line. The measurement of the static linearity performance requires the application of a low frequency high linearity stimulus and the collection of a high volume of output samples for noise averaging, usually using a histogram-based test setup. Thus, as the resolution of state-of-the-art ADCs increases, test time for static linearity characterization increases exponentially. For this reason, the reduction of the ADC test time is a hot topic that has gained an increasing interest over the past years. New techniques have recently been proposed to effectively reduce test time, but no BIST technique has yet been developed that considers a high resolution signal generator in combination with an on-chip analysis technique that dramatically reduces the amount of data. In this thesis, static linearity BIST techniques will be investigated for pipeline ADCs. In particular, this thesis presents a novel high-linearity on-chip test stimulus generator and a modified servo-loop technique that, in combination with reduced-code linearity test algorithms, lead to the definition of an efficient and accurate BIST strategy for pipeline ADCs. The work includes the experimental validation of the proposed techniques in collaboration with STMicroelectronics, Grenoble.