On-Chip AHB Bus Trace Analyzer for Real Time Tracing With Lossless Data Compression

The advanced micro controller bus  Architecture (AMBA) is widely used as the on-chip bus in System-on-Chip(SoC) designs. The important aspect of a SoC is not only which components or blocks it houses, but also how they are interconnected. AMBA is a solution for the blocks to interface with each other. The objective of the AMBA specification is to be technology independent, minimize silicon infrastructure while supporting high performance and low power on-chip communication. The biggest challenge in SoC design is in validating and testing the system. The Advanced High-performance Bus (AHB) is a part of the Advanced Microcontroller Bus Architecture (AMBA). Performance can be improved at high-frequency operation. Performance is independent of the mark-space ratio of the clock. No special considerations are required for automatic test insertion. Our aim in this project is to design the AHB- protocol with bus tracer. For real-time tracing, we should reduce the trace size as much as possible without reducing the original data. The experimental results show that trace compression ratio reduced by 96.32%. Finally this approach was designed successfully along with MODEL SIM and synthesis using Xilinx ISE. The SoC can be verified in field-programmable gate array

Design of an Embedded Readout System for the ALOFT Gamma-Ray Detector Instrument

Birkeland Center for Space Science has proposed a campaign known as the Airborne Lightning Observatory for FEGS & TGFs (ALOFT) to study Terrestrial Gamma-Ray Flashes (TGFs). TGFs are the most energetic natural phenomena occurring in the Earth’s atmosphere, and are important to our knowledge about the relationship between the Earth and space. The ALOFT campaign will use a gamma-ray detector instrument built by the University of Bergen which will be mounted to the NASA ER-2 High-Altitude Airborne Science Aircraft. This work covers the design and development of the embedded software used to offload and operate the detector readout system of said instrument. A similar instrument was built and flown in 2017. The new instrument differs from this by being implemented on a System on a Chip (SoC) embedded platform, reusing relevant modules from the old instrument. The software has been implemented with the FreeRTOS Realtime Operating System (RTOS). Design considerations to limit complexity, and the impact of the radiation environment the instrument is to be operated in, has been performed trough implementation of a checksum algorithm, cyclic rewriting of registers, and modular design strategies. A verification system has been realized with a prototype hardware setup, in which test systems has been added to process synthetic TGF-events in the software and hardware. Test with emulated data and a Telnet control interface has been successfully implemented. The current implementation focuses on modularity, and thus offers a very good framework for further development of the instrument when campaign specifications are decided.Masteroppgåve i fysikkMAMN-PHYSPHYS39

Testability considerations for implementing an embedded memory subsystem

textThere are a number of testability considerations for VLSI design, but test coverage, test time, accuracy of test patterns and correctness of design information for DFD (Design for debug) are the most important ones in design with embedded memories. The goal of DFT (Design-for-Test) is to achieve zero defects. When it comes to the memory subsystem in SOCs (system on chips), many flavors of memory BIST (built-in self test) are able to get high test coverage in a memory, but often, no proper attention is given to the memory interface logic (shadow logic). Functional testing and BIST are the most prevalent tests for this logic, but functional testing is impractical for complicated SOC designs. As a result, industry has widely used at-speed scan testing to detect delay induced defects. Compared with functional testing, scan-based testing for delay faults reduces overall pattern generation complexity and cost by enhancing both controllability and observability of flip-flops. However, without proper modeling of memory, Xs are generated from memories. Also, when the design has chip compression logic, the number of ATPG patterns is increased significantly due to Xs from memories. In this dissertation, a register based testing method and X prevention logic are presented to tackle these problems. An important design stage for scan based testing with memory subsystems is the step to create a gate level model and verify with this model. The flow needs to provide a robust ATPG netlist model. Most industry standard CAD tools used to analyze fault coverage and generate test vectors require gate level models. However, custom embedded memories are typically designed using a transistor-level flow, there is a need for an abstraction step to generate the gate models, which must be equivalent to the actual design (transistor level). The contribution of the research is a framework to verify that the gate level representation of custom designs is equivalent to the transistor-level design. Compared to basic stuck-at fault testing, the number of patterns for at-speed testing is much larger than for basic stuck-at fault testing. So reducing test and data volume are important. In this desertion, a new scan reordering method is introduced to reduce test data with an optimal routing solution. With in depth understanding of embedded memories and flows developed during the study of custom memory DFT, a custom embedded memory Bit Mapping method using a symbolic simulator is presented in the last chapter to achieve high yield for memories.Electrical and Computer Engineerin

From FPGA to ASIC: A RISC-V processor experience

This work document a correct design flow using these tools in the Lagarto RISC- V Processor and the RTL design considerations that must be taken into account, to move from a design for FPGA to design for ASIC

A multiprocessor based packet-switch: performance analysis of the communication infrastructure

The intra-chip communication infrastructures are receiving always more attention since they are becoming a crucial part in the development of current SoCs. Due to the high availability of pre-characterized hard-IP, the complexity of the design is moving toward global interconnections which are introducing always more constraints at each technology node. Power consumption, timing closure, bandwidth requirements, time to market, are some of the factors that are leading to the proposal of new solutions for next generation multi-million SoCs. The need of high programmable systems and the high gate-count availability is moving always more attention on multiprocessors systems (MP-SoC) and so an adequate solution must be found for the communication infrastructure. One of the most promising technologies is the Network-On-Chip (NoC) architecture, which seems to better fit with the new demanding complexity of such systems. Before starting to develop new solutions, it is crucial to fully understand if and when current bus architectures introduce strong limitations in the development of high speed systems. This article describes a case study of a multiprocessor based ethernet packet-switch application with a shared-bus communication infrastructure. This system aims to depict all the bottlenecks which a shared-bus introduces under heavy load. What emerges from this analysis is that, as expected, a shared-bus is not scalable and it strongly limits whole system performances. These results strengthen the hypothesis that new communication architectures (like the NoC) must be found

Performance Considerations for an Embedded Implementation of OMA DRM 2

As digital content services gain importance in the mobile world, Digital Rights Management (DRM) applications will become a key component of mobile terminals. This paper examines the effect dedicated hardware macros for specific cryptographic functions have on the performance of a mobile terminal that supports version 2 of the open standard for Digital Rights Management defined by the Open Mobile Alliance (OMA). Following a general description of the standard, the paper contains a detailed analysis of the cryptographic operations that have to be carried out before protected content can be accessed. The combination of this analysis with data on execution times for specific algorithms realized in hardware and software has made it possible to build a model which has allowed us to assert that hardware acceleration for specific cryptographic algorithms can significantly reduce the impact DRM has on a mobile terminal's processing performance and battery life.Comment: Submitted on behalf of EDAA (http://www.edaa.com/

Implementing a hybrid series bus with gas turbine device - a preliminary study

This paper presents the implementation of an hybrid series Bus with a gas turbine, as thermal engine. The hybridization methodology for transforming city buses, substituting the original gasoline/diesel engine with a micro gas turbine device (intended as range extender), into a series hybrid vehicle has investigated and its feasibility analyzed. The study was conducted by the university of Rome “Sapienza” in collaboration with several enterprises. The idea is to design a hybrid power train that can be installed in a typical city bus, which means that all systems and components will be influenced by the limited space available. In this paper the details of the mechanical and electrical realization of the power train will be discussed. The hybrid system also includes consideration on the battery pack and the vehicle management logic. The proposed solution obtains a reduction in fuel consumption higher than 20%, in comparison with normal commercial fleet

Synthetic considerations in the self-assembly of coordination polymers of pyridine-functionalised hybrid Mn-Anderson polyoxometalates

The incorporation of polyoxometalates (POMs) as structural units into ordered porous constructs such as metal-organic frameworks (MOFs) is desirable for a range of applications where intrinsic properties inherited from both the MOF and POM are utilised, including catalysis and magnetic data storage. The controlled self-assembly of targeted MOF topologies containing POM units is hampered by the wide range of oxo and hydroxo units on the peripheries of POMs that can act as coordinating groups towards linking metal cations leading to a diverse range of structures, but incorporation of organic donor units into hybrid POMs offers an alternative methodology to programmably synthesise POM/MOF conjugates. Herein, we report six coordination polymers obtained serendipitously wherein Zn2+ and Cu2+ link pyridine-appended Mn-Anderson clusters into two- and three-dimensional network solids with complex connectivities and topologies. Careful inspection of their solid-state structures has allowed us to identify common structure-directing features across these coordination polymers, including a square motif where two Zn2+ cations bridge two POMs. By correlating certain structural motifs with synthetic conditions we have formulated a series of design considerations for the self-assembly of coordination polymers of hybrid POMs, encompassing the selection of reaction conditions, co-ligands and linking metal cations. We anticipate that these synthetic guidelines will inform the future assembly of hybrid POMs into functional MOF materials

MAPPING SOIL ORGANIC CARBON DYNAMICS OVER THE LAST DECADES IN MEDITERRANEAN AGRO-ECOSYSTEMS WITH LEGACY DATA

Summary Soil organic carbon (SOC) represents the biggest carbon pool of the biosphere, bigger than the living plant pool. In agriculture, SOC is of pivotal importance for sustainable soil management and is a main soil fertility indicator. As soils are responsible for food production and the provision of various ecosystem services, there is a sturdy interest in understanding how land use and management affect natural plant and crop growth, and ecosystem resilience and functioning. These processes require time and soil sustainability is to be evaluated in a long-term economic perspective by policy makers with the aim of maintaining adequate, and likely improved, conditions of the soil and the whole farm for the future. Thus, long-term actions for crop sustainability could also admit little short-time yield reduction if yield potential, stability and environmental health are maintained at the long-time. Food production and ecosystem services provision depend on the maintenance, or increase, of SOC in agricultural soil, since SOC act as a short-term nutrient reservoir, increase water holding capacity and soil infiltration rate, reduce soil compaction, and favour soil resilience against pollutants. These effects should be taken into account at both a narrow and broad geographical breadth. When aiming to manage SOC at broad geographical extent, a detailed knowledge of SOC distribution and likely change in time is required. However, such a knowledge relies on correct sampling method and modelling procedures that in turn depend on the environmental variability of the area under study. Mediterranean areas are frequently variable as an harbour, the area has been subjected to a high share of soil and above-ground biodiversity and experienced long cultivation history and intensification since the last century, which increased their fragility. In this environment, the acquisition of reliable information on SOC can require a highly dense sampling, which can also negatively affect some relict environment. In addition, sampling can imply a high cost for field work and laboratory analyses. The aim of my Ph.D. work was thus to investigate the main factors related to SOC spatial distribution in agricultural land under various pedoclimatic conditions in semiarid Mediterranean areas, using a legacy soil database (1968-2008) of SOC and soil bulk density. The dissertation is structured in six chapters: the first one is a general introduction where the rationale of the dissertation is explained, and the research questions are stated. The second chapter is a novel approach to systematically collecting literature from international peer-review issues, namely systematic map. The third one is an analysis of the legacy soil database, which intends to make the database ready to be used for the SOC assessment and for the digital soil mapping. The fourth chapter touches an issue dealing with SOC stock mapping with the boosted regression tree and a set of covariates to produce local SOC benchmarks to be compared with European and Global SOC maps. The fifth chapter fits in the same modelling frame and it is addressed at the SOC dynamics using the most widespread legacy sampling campaign. A high number of available spatial data were collected and computed and used to calibrate the SOC models. At this stage, due to the ungridded structure of the data, a machine learning based model has been used (Boosted Regression Trees). The last chapter is a comparison of models (geostatistical, machine learning and linear), and shows useful information about the way that the error is reported by each algorithm. Soil maps are not just produced for the sake of creating attractive geographical visualizations: they have a very precise task to fulfil, i.e. provide accurate and reliable information on soil properties that decision makers can use to plan interventions of any kind. The use of the Regression Kriging and Boosted Regression Trees models, which resulted in the best prediction performance in terms of R2 and RMSE, highlighted the SOC dependence on environmental factors, and the prediction of the agricultural land covers. All land cover groups were studied in the preliminary stage of this study (chapter 2), while only the cropland identified with the legacy data was the candidate for the development of the final models which lead to the detection of a positive SOC trend. The last chapter aimed at the comparison between geostatistical, machine learning and linear models to predict SOC in agricultural lands, and an improvement in local uncertainty estimation. The outstanding result was that SOC at the monitoring sites were accurately simulated, being in full agreement with observed data. Once more, actual data will be available and the model will be calibrated and validated, a model of SOC potential sequestration regional scale can be produced. The results of this dissertation has led to a clear and shared vision in the community regarding the selection of the estimation methods for SOC prediction needs to be based on careful considerations. It is good practice to test algorithms already used in literature for similar purposes, but it may be counterproductive to only look at an algorithm because it is new and never used before in a particular field. This sometimes happens in science where methods are selected only because fashionable and not based on real and tested experiments. In the dissertation the origin of the data was sometimes know and sometimes it has been data driven based. In particular, sampling design was based on geostatistics only in the 2008 campaign and it may well be that looking at very advanced methods like deep-learning could be interesting, but still less accurate than the geostatistical kriging based algorithms, which can also provide robust and well tested uncertainty estimations. In summary, even though we have now access to advanced algorithms it does not mean that we need to use them blindly without fully considering what we are trying to achieve with our working hypothesis and research question

A mechatronic approach to supernormal auditory localisation

Remote audio perception is a fundamental requirement for telepresence and teleoperation in applications that range from work in hostile environments to security and entertainment. The following paper presents the use of a mechatronic system to test the efficacy of audio for telepresence. It describes work to determine whether the use of supernormal inter-aural distance is a valid means of approaching an enhanced method of hearing for telepresence. The particular audio variable investigated is the azimuth angle of error and the construction of a dedicated mechatronic test rig is reported and the results obtained. The paper concludes by observing that the combination of the mechatronic system and supernormal audition does enhance the ability to localise sound sources and that further work in this area is justified