Implementing boundary scan test strategies

It is shown that interconnect testing for boards that mix boundary scan and conventional components can be performed effectively by a four-stage strategy: a conventional shorts test where the tester has access, a scan circuitry integrity test, a fairly conventional boundary scan interconnect test, and a test for shorts between the boundary scan and conventional parts of the circuit, which is new. There are a number of complications so that careful analysis of the results is needed, even for the conventional parts of the test, but this strategy can be used to give a precise, usable diagnosis of the problems. It is noted that a circuit is not necessarily testable just because it contains boundary scan parts. The test access port on those components is a potential weak link, and physical access to those signals is necessary to get good diagnosis. In addition, it may be impossible to diagnose accurately shorts involving nodes with neither physical access nor boundary scan access, and that may even repeatedly not be detectable. >

This paper describes the use of boundary scan based tests and embedded built in test (BIT) software in the manufacturing defects testing of a 100 MHz, high density, surface mount multi-chip-module, parallel processing computer.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

The components and the solder joints that are made during assembly to hold components to their printed circuit board can suffer from defects and therefore need to be tested. Many research papers on board-Assembly testing focus on boundary scan test, processor-controlled test, or other powered digital testing techniques that mostly ignore the indispensable passive circuits and that can incur damage that could have been avoided by executing a non-powered test first. In-circuit testing is a non-powered test method that applies stimuli and measures responses using probe needles. However, often used self-learning solutions for designing these tests need a known-good-board, entailing significant disadvantages. In this paper, a software tool is described that automatically generates in-circuit tests based on the product design files, without requiring probe access on every net. Furthermore, the tool indicates where on the board fault coverage is not maximal, and hence where extra probe access will improve the test quality.

This article discusses the development of a board level manufacturing test for a surface mount board implemented with boundary scan. The board examined is a composite of several actual products. Methods for effectively developing a boundary scan test are examined along with some of the advantages of approaching the development in unique ways. Additionally, the criteria for using these methods are developed. Results for test development time and the resulting test coverage show that with two weeks of test development using boundary scan it is possible to increase the rate of solder opens detection from 80% to 99% for a large ball-grid-array module.

A novel test strategy, the Loop Testing Architecture (LTA), is introduced to reduce aliasing probability and testing time for multichip modules. This is accomplished by connecting cascadable built-in testers (CBITs) in neighboring pipelined stages to increase the length of the test suites. Fundamental properties of the LTA supporting randomness in the generated test patterns (state coverage) and the asymptotic aliasing probability are presented. Results on two small-scale multiprocessor configurations show that the aliasing probability in analyzing signatures is comparable to that of an MLFSR but with fairly low area overhead; compared with the circular self-test path technique, less testing time is required by LTA. Further evaluation of the potential capabilities provided by the LTA compared with boundary scan and other pipelined test scheduling approaches confirmed the usefulness of LTA as a framework for designing effective testable systems.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

With the fast development of electronic industry,the techniques of testing electronical system have varied from traditional functional test to structured test accordingly.The principel of functional test is presented in this paper and the representative techniques of structured test, as in-circuit test(ICT),boundary-scan test(BST),build-in self-test(BIST) and scan-path test,are explored subsequently.Finally,the developmenting trends in the future are looked forward to.

This paper focuses on the practical aspects of combining boundary scan testing with traditional In-Circuit Test. The fault coverage, diagnostic, fixturing, and throughput benefits that can be realized by testing with a combined BSCAN/ICT strategy are described, along with the specific issues and challenges involved in providing a comprehensive BSCAN/ICT solution.

This study examines the dynamics of language maintenance at Istana Dalam Loka, focusing on the role of various domains in both physical and virtual access to the site. Utilizing data from Google Search and Google Trends, the research analyzes the prevalence of different domains—tourism, historical and cultural, religious, entertainment, and educational—within the virtual landscape, and compares them to their physical reality. The findings indicate that tourism is the most dominant domain, both in physical and virtual contexts, followed by historical and cultural activities. However, despite the stream of external influences through tourism, the study reveals a strong resistance to language and cultural differences, as the local Sumbawa culture remains deeply rooted in activities conducted at Istana Dalam Loka. This cultural resistance suggests that Sumbawa language and cultures are being maintained through a process similar to a sociolinguistic diversity of 'melting pot,' where diverse languages and cultures are integrated to the Sumbawa language and culture. The study concludes that while virtual access offers an alternative platform for language contact and multicultural engagement, it is primarily locals who both produce and consume content related to Istana Dalam Loka in virtual access. It also ensures the continued dominance of Sumbawa language and culture. Keywords: domain, Istana Dalam Loka, language maintenance, Sumbawa language and culture, virtual access

A boundary scan scheme is introduced that uses multiple-valued logic signaling to reduce the number of chip pins and on-chip control signal lines, which leads to a decrease in the chip area overhead as well as interconnection complexity. The various modes of operation in the proposed scheme are defined by the quaternary control line CS (control signal). Also encoded on CS is the clock signal used to synchronize the data movement in the boundary scan shift register path. The proposed scheme does not allow the application of the clock pulses through BSI during the apply test mode of operation. However, application of clock pulses during this mode has no apparent use since data cannot be shifted out. >

In a fundamental paradigm shift in system design, entire systems are being built on a single chip, using multiple embedded cores. Though the newest system design methodology has several advantages in terms of time-to-market and system cost, testing such core-based systems is difficult, mainly due to the problem of justifying test sequences at the inputs of a core embedded deep in the circuit and propagating test responses from the core outputs. In this paper, we first present a design for testability technique for testing such core-based systems. In this scheme, untestable cores are first made testable using hierarchical testability analysis techniques. If necessary, additional testability hardware is added to the cores to make them transparent so that they can propagate test data without information loss. This testability and transparency technique is currently applicable to cores of the following types: application-specific integrated circuits, application-specific programmable processors, and application-specific instruction processors. Other core types can be made testable and transparent using traditional techniques. The testable and transparent cores can then he integrated together with some system-level testability hardware to ensure justification of precomputed test sequences of each core from system primary inputs to the core inputs and propagation of test responses from core outputs to system primary outputs. Justification and propagation of test sequences are done at the system level by extending and suitably modifying the symbolic hierarchical testability analysis method that has been successfully applied to register-transfer level circuits. Since the testability analysis method is symbolic, the system test generation method is independent of the bit-width of the cores. The system-level test set is obtained as a byproduct of the testability analysis and insertion method without further search. The test methodology was applied to six example systems. Besides the proposed test method, the two methods that are currently used in the industry were also evaluated: (1) FScan-BScan, where each core is full-scanned, and system test is performed using boundary scan and (2) FScan-TBus, where each core is full-scanned, and system test is performed using a test bus. The experiments show that the proposed scheme has significantly lower area overhead, delay overhead, and test application time compared to FScan-BScan and FScan-TBus, without any compromise in the system fault coverage.

Three ASIC (application-specific integrated circuit) devices recently designed at AT&T incorporate the ANSI/IEEE Std 1149.1-1990 testability features. The test port is used for control of on-chip boundary-scan (BS) and full chip (macrocell and random logic) built-in-self-test (BIST). Presented are a view of the methods used for implementation, novel circuit sharing between BIST and BS, and results related to device area, performance, fault coverage, and testing. The availability of boundary-scan allowed automatic generation of board-level test vectors and allowed board-level printed wire testing without bed-of-nails techniques. By applying BIST tools to the devices after functional design, fault coverage of all of the ASICs was increased to acceptable levels without the significant time and expense of manual vector writing.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

The development and implementation of novel diagnostic techniques has had a profound effect on microbiology laboratory services in recent decades. Traditional microscopy, culture and biochemical testing techniques have been the mainstay for identification and anti-microbial susceptibility testing of microorganisms for generations (1,2). While these tests remain the core basis and standard practice in most laboratories, new techniques, such as nucleic acid-based assays and mass spectrometry, are increasingly being used. In some cases, these are enhancing existing diagnostic algorithms and, in others, they are replacing traditional testing approaches. Although these new techniques are powerful and offer many potential advantages over traditional methods, they have a number of limitations. In the present note, we briefly review new and evolving testing modalities in the microbiology laboratory. It is important to note that we did not intend to provide an in-depth technical appraisal of testing modalities. Rather, our objective was to highlight a number of new testing modalities in the context of traditional testing for bedside clinicians.

The New Institutional Economics (NIE) occupies an important space in the rapidly expanding theory of organization. Traditional testing techniques have only been applied to less complex parts of the NIE. A rich body of evidence generated by the experiences of firms and other organizations lies fallow. The limited domain of traditional testing will persist because of the nature of the central concepts of the NIE, the difficulty posed for integrating transaction cost into an optimizing framework by self-reference, and the particularly wicked manifestations of the Duhem-Quine problem. Experimental economics may add credibility to some components of the NIE but is unlikely to fill the current void. The catchy title, the telling anecdote, and the creative 'fact' have played a disproportionate role in determining the composition of the canonical literature in the NIE. Catalytic steps for developing professional norms governing the marshalling of data generated by different organizations and institutions are discussed in the concluding section.

Elementary Explanation: How “Boundary Scan Test” Works

Two generations of High Definition Television decoders have been developed and produced. Boundary scan test was successfully implemented in the latter generation, and proved to be the design for test solution for the future.