A Cross-level Verification Methodology for Digital IPs Augmented with Embedded Timing Monitors

Smart systems implement the leading technology advances in the context of embedded devices. Current design methodologies are not suitable to deal with tightly interacting subsystems of different technological domains, namely analog, digital, discrete and power devices, MEMS and power sources. The interaction effects between the components and between the environment and the system must be modeled and simulated at system level to achieve high performance. Focusing on digital subsystem, additional design constraints have to be considered as a result of the integration of multi-domain subsystems in a single device. The main digital design challenges combined with those emerging from the heterogeneous nature of the whole system directly impact on performance, hence propagation delay, of the digital component. In this paper we propose a design approach to enhance the RTL model of a given digital component for the integration in smart systems, and a methodology to verify the added features at system-level. The design approach consists of ``augmenting'' the RTL model through the automatic insertion of delay sensors, which are capable of detecting and correcting timing failures. The verification methodology consists of an automatic flow of two steps. Firstly the augmented model is abstracted to system-level (i.e., SystemC TLM); secondly mutants, which are code mutations to emulate timing failures, are automatically injected into the abstracted model. Experimental results demonstrate the applicability of the proposed design and verification methodology and the effectiveness of the simulation performance

A Cross-level Verification Methodology for Digital IPs Augmented with Embedded Timing Monitors

Smart systems are characterized by the integration in a single device of multi-domain subsystems of different technological domains, namely, analog, digital, discrete and power devices, MEMS, and power sources. Such challenges, emerging from the heterogeneous nature of the whole system, combined with the traditional challenges of digital design, directly impact on performance and on propagation delay of digital components. This article proposes a design approach to enhance the RTL model of a given digital component for the integration in smart systems with the automatic insertion of delay sensors, which can detect and correct timing failures. The article then proposes a methodology to verify such added features at system level. The augmented model is abstracted to SystemC TLM, which is automatically injected with mutants (i.e., code mutations) to emulate delays and timing failures. The resulting TLM model is finally simulated to identify timing failures and to verify the correctness of the inserted delay monitors. Experimental results demonstrate the applicability of the proposed design and verification methodology, thanks to an efficient sensor-aware abstraction methodology, by applying the flow to three complex case studies

Monitor amb control strategies to reduce the impact of process variations in digital circuits

As CMOS technology scales down, Process, Voltage, Temperature and Ageing (PVTA) variations have an increasing impact on the performance and power consumption of electronic devices. These issues may hold back the continuous improvement of these devices in the near future. There are several ways to face the variability problem: to increase the operating margins of maximum clock frequency, the implementation of lithographic friendly layout styles, and the last one and the focus of this thesis, to adapt the circuit to its actual manufacturing and environment conditions by tuning some of the adjustable parameters once the circuit has been manufactured. The main challenge of this thesis is to develop a low-area variability compensation mechanism to automatically mitigate PVTA variations in run-time, i.e. while integrated circuit is running. This implies the development of a sensor to obtain the most accurate picture of variability, and the implementation of a control block to knob some of the electrical parameters of the circuit.A mesura que la tecnologia CMOS escala, les variacions de Procés, Voltatge, Temperatura i Envelliment (PVTA) tenen un impacte creixent en el rendiment i el consum de potència dels dispositius electrònics. Aquesta problemàtica podria arribar a frenar la millora contínua d'aquests dispositius en un futur proper. Hi ha diverses maneres d'afrontar el problema de la variabilitat: relaxar el marge de la freqüència màxima d'operació, implementar dissenys físics de xips més fàcils de litografiar, i per últim i com a tema principal d'aquesta tesi, adaptar el xip a les condicions de fabricació i d'entorn mitjançant la modificació d'algun dels seus paràmetres ajustables una vegada el circuit ja ha estat fabricat. El principal repte d'aquesta tesi és desenvolupar un mecanisme de compensació de variabilitat per tal de mitigar les variacions PVTA de manera automàtica en temps d'execució, és a dir, mentre el xip està funcionant. Això implica el desenvolupament d'un sensor capaç de mesurar la variabilitat de la manera més acurada possible, i la implementació d'un bloc de control que permeti l'ajust d'alguns dels paràmetres elèctrics dels circuits