Atpg test coverage in software

The goal of atpg is to set all nodes of the circuit to both 0 and 1, and to propagate any defects to nodes where they can be detected by test equipment. Tackling low atpg test coverage in tessent dft india. Amount of testing performed by a set of test cases is called test coverage. The cellaware test approach starts with an automated cell library characterization process, which is illustrated in figure 1. It helps in evaluating the effectiveness of testing by providing data on different. Atpg tools like tessent have evolved to be able to automatically analyze fault data and help the dft engineer to reduce the gap in the scan coverage. The scanexpress tpg intelligent test pattern generator software provides a highly advanced, automated boundaryscan test design environmentperfect for quick and efficient creation of complete boundaryscan tests for all ieee1149. Howto create comprehensive test coverage reports during. Encountering millions of flops per design block has become a common occurrence in todays socs. Nov 15, 2019 the traditional sa tr atpg and ca atpg are performed with the tessent tool from mentor, a siemens businessgraphics. Test coverage in software testing tips to maximize testing.

In computer science, test coverage is a measure used to describe the degree to which the source code of a program is executed when a particular test suite runs. Best practices of test coverage in software testing. A recently introduced atpg based test methodology achieves the needed efficiency improvements by directly targeting specific defects internal to each cell 1. The fully onchip lbist applies pseudorandom patterns to the circuit and responses are collected in a multiinput signature register misr. The knowledge gained for generating test patterns in this class is directly applicable for generating test patterns for designs utilizing tessent testkompress. Test coverage in software testing tips to maximize. So in this post, well take a critical look at this practice. Most of the work is to find the best test coverage with the shortest pattern. Read this blog to understand test coverage, its techniques, metrics, matrix and.

Considerations for implementing atspeed tests will be discussed as well as. Improving the test coverage is essential in detecting manufacturing defects in semiconductor industry so that high quality products can be supplied to consumers. A program with high test coverage, measured as a percentage, has had more of its source code executed during testing, which suggests it has a lower chance of containing undetected software bugs compared to a program with low test coverage. Harzardbased atpg for improving delay test quality. Synopsys tetramax is used to perform atpg automatic test pattern generation and fault simulation.

Lbist a technique for infield safety design and reuse. Highly optimized, memoryefficient test generation, and fault simulation engines for orderofmagnitude faster atpg runtime compared to previous technologies. The scan test coverage improvement by using automatic test pattern generation atpg tool configuration was investigated. Jan 01, 2015 test coverage measures the amount of testing performed by a set of test cases. Company standardizes on tetramax ii solution to create manufacturing tests for all designs. The results table shows the percentage of the code that was run in each assembly, class, and method. Test coverage metrics to measure the code quality reqtest. Atpg could be modified to test reachability and performance. Use atpg algorithm to generate test patterns apply patterns and capture outputs without simulating faults produces expected output for each test pattern fault determine fault coverage of a set of patterns user provides a set of test patterns and fault list perform fault simulation using these patterns and faults to determine coverage atpg.

Logic builtin self test lbist helps to reduce the testing complexity by order of magnitude. Two test strategies are used to test virtually all ic logic. It delivers unparalleled runtime, ensuring patterns are ready when early silicon samples are available for testing. Clock and reset signals to the nonscan elements do not need to be controllable at the primary inputs.

However, today ic manufacturers typically employ many different tests which are either sourced from automatic test pattern generation atpg software or are fault graded using fault simulation, examples of which are stuckat tests, transition tests, and iddq tests. Yet questions lurk around how effective it is to use test coverage metrics to measure code quality. Atpg test methodology physical ip blog physical arm. It will include gathering information about which parts of a program are executed when running the test suite to determine which branches of.

Debugging low testcoverage situations electronic design. Test coverage is an important indicator in software testing in terms of quality and effectiveness. Automatic test pattern generation atpg automatic test pattern generation, or atpg, is a process used in semiconductor electrical testing wherein the vectors or input patterns required to check a device for faults are automatically generated by a program. The focus in the article is on automatic testpatterngeneration tools. Software aided failure analysis using atpg tool ieee. A pattern set with 100% stuckat fault coverage consists of tests to detect every possible stuckat fault in a circuit.

In other words, test coverage is defined as a technique which determines whether our test cases are actually. Dec 18, 2014 this is the fourth in a series on how to understand and debug test coverage issues in the tessent atpg tools. Incorporate testmax atpg in a design and test methodology that produces desired fault coverage, atpg vector count and atpg runtime for a fullscan or almost fullscan design. Improving atpg gatelevel fault coverage by using test vectors. Development is more systematic nowadays and organizations seek. Using the cadence modus dft software solution you can experience an upto3x reduction in test time. This is compared to 1detect or 5detect approach effectively reducing test cost. Automatic test pattern generation atpg tools known as victory are comprehensive set of software tools that are used to generate test patterns and obtain diagnostic information for electronic assemblies containing boundary scan devices. When creating atspeed or near atspeed test patterns in an atpg tool, it is very important to provide the tool with this same timing exception information that was used by the sta tool. In order to improve test coverage, an efficient automatic test pattern generation atpg method especially aimed at hazardbased. What are some misconceptions software engineers have about unit test coverage. Snps, today announced that stmicroelectronics is seeing significantly faster test pattern generation runtime and reduced number of patterns with tetramax ii atpg. I found out that the pattern files are generated by an atpg software called tetramax, but we dont have access to the software.

Finegrained multithreading across multiple cores overcomes memory bottlenecks. Hybrid atpg lbist and hybrid test points a hybrid atpg lbist test strategy increases manufacturing test coverage and improves in system test for missioncritical automotive ics. Reduce test time by up to 3x without impact to fault coverage or chip size. Systematic methodology with df t rules reduces faultcoverage. The toolset also includes testability analysis tools for designing boards with boundary scan devices. Atpg acronym for both automatic test pattern generation and automatic test pattern generator is an electronic design automation methodtechnology used to find an input or test sequence that, when applied to a digital circuit, enables automatic test equipment to distinguish between the correct circuit behavior and the faulty circuit behavior caused by defects. Automatic test pattern generation atpg tools known as victory are comprehensive set of software tools that are used to generate testpatterns and obtain diagnostic information for electronic assemblies containing boundary scan devices. Introducing a new patented 2d elastic compression architecture, this nextgeneration tool enables compression ratios beyond 400x without impacting design size or routing. Identical test coverage and pattern reduction across different server configurations and machines for. Generating the actual test pattern is the least problem.

Design for test dft insert test points, scan chains, etc. Now i want i would like to know how can i increase the coverage both test as well as fault coverage. Apr 15, 2020 test coverage is defined as a metric in software testing that measures the amount of testing performed by a set of test. Read this blog to understand test coverage, its techniques, metrics, matrix and how to improve it. Interpreting atpg statistics fault coverage vs test coverage identification and quantification of coverage issues.

By modifying the atpg commands, it can be expected to have some improvement in the test coverage. Lecture 14 design for testability stanford university. Estimate test coverage scan synthesis flow hdl scanready synthesis. However, early generation of few high level test patterns can provide higher test quality and reduce atpg effort. Automatic test packet generation stanford university. It was put forward by suresh kumar devanathan from rake software and michael bushnell, rutgers university. The 2d elastic compression architecture in the cadence modus dft software solution consists of.

Why test coverage is important in software testing. Victory automatic test pattern generation tools atpg. High test coverage of these designs directly correlates to the. We can use test management tools to perform functional test coverage which will establish traceability between, requirements, defects and test cases. Automatic test pattern generation atpg is a softwarebased approach that can be applied to any. Automatic testpattern generation atpg has played a key role in semiconductor logic test, but several trends driving the need for semiconductor test quality are challenging traditional atpg tools. In software testing, test coverage measures the amount of testing performed by a set of test. In atpg, test packets are generated algorithmically from the device con guration les and fibs, with the minimum number of packets required for complete coverage.

A hybrid test approach combining atpg and bist semiwiki. Automatic test generation products atg, atpg, atvg for programmable logic devices pld, epld, fpga, small gate array, boundary scan jtag, 1149. Test coverage measures the amount of testing performed by a set of test. Test coverage is an important indicator of software quality and an essential part of software maintenance. Below is the coverage report after testbench generation using tetramax tool. Test coverage is defined as a metric in software testing that measures the amount of testing performed by a set of test. Stuckat0 refers to a net segment being stuck at logic 0, stuckat1 to logic 1. Atpg also uses test compression techniques to reduce the number of test patterns in the process. Software aided failure analysis using atpg tool abstract. Learn how automated debug analysis can help you close the gap in scan coverage on your. Using boundary scan chains in this way during atpg helps to improve test coverage, particularly for lowpin count designs. With a complete suite of industrystandard capabilities for memory bist, logic bist, test point insertion, and diagnostics, the solution can help you reduce your production test costs and increase silicon profit margins. It should read in the fault coverage result provided by atpg tool and add to it any additional coverage provided by non atpg test vectors. It would be helpful if i could find out whether there is a norm for the test vectors.

Jul 12, 2016 achieves significant testpatterncount reduction without impacting test coverage. Fullsequential atpg, like fastsequential atpg, supports multiple capture cycles between scan load and unload, thus increasing test coverage in partialscan designs. Test design more difficult after design frozen basic steps. Fault coverage is a popular test criterion in delay testing. For failure analysis, some standard atpg tools offer in addition a feature to perform fault diagnosis on full scan designs. In the world of ic testability we tend to look at various approaches as independent means to an end, namely high test coverage with the minimum amount of test time, minimum area impact, minimum timing impact, and acceptable power use. Atpg is an electronic design automation methodtechnology used to find an input or test.

The tessent shell database simplifies and automates test coverage reporting while generating more accurate reports, lowering atpg runtime, and providing detailed fault categories for debug purposes. It will include gathering information about which parts of a program are executed when running the test suite to determine which branches of conditional statements have been taken. Requirements may include things like functioality, propagation delays, at speed tests, setup and hold times, jitter performance, etc. In software based self test the device checks its components functionality by providing functional test vectors and reads the response to check the pass or fail status. We can use bi directional traceability matrix to achieve test coverage. Software testing could be an option for infield latent fault detection but pattern generation in this case is manual and may not provide sufficient coverage in a given time frame. Mentor graphics reserves the right to make changes in specifications and other information contained in this publication without prior notice, and the. Next, generated test patterns are simulated by using simulator and correctness of these methods are verified. Atpg is needed to devise the test content with high fault coverage. How to test more, save time, and achieve better testing results.

Wherever we can count things and can tell whether or not each of those things has been tested by some test, then we can measure coverage and is known as test coverage. Using timing constraints for generating atspeed test. Generates highcoverage test patterns in hours instead of days. Lab1 scanchain insertion and atpg nctu vlsi testing lab. Therefore, it is of paramount importance that your fault simulator understand the output files of your atpg tool. If they have a detrimental effect on the design and if that effect is detectable, then the purpose of scan testing is to automatically generate a scan vector or vectors to detect it by using an automatic testpatterngeneration atpg tool. Create a stil test protocol file for a design by using quick stil menus or commands, testmax dft, or from scratch. The test pattern generator creates patterns that always. The scan test patterns generated were stuckat test patterns.

The left figure in figure 5 shows that ca patterns can achieve same test coverage with fewer patterns. By amount of testing we mean that what parts of the application program are exercised when we run a test suite. Testmax atpg is synopsys stateoftheart pattern generation solution that. Using the cadence modus dft software solution you can experience an upto3x reduction in test time using its patented physically aware 2d elastic compression architecture, without any impact on fault coverage or chip size. Automatic testpattern generation atpg tools have evolved to be able to automatically analyze fault data. Catalog pdf catalog html literature boundary scan pldsfpgas device lists other sites. Apr 11, 2017 test coverage generally refers to how thorough the test program is compared against requirements. Code coverage testing visual studio microsoft docs. Basically, dftbased test consists of various components, such as fault models, automatic test pattern generation atpg and compression. Atpg architecture 20 circuit description reduced fault list test pattern fault simulator fault coverage tpg algorithm. An obvious question that comes to mind now, is what should you go for.

Some faults in the tap logic should be covered by scan testing itself, such as those. Atpg architecture 20 circuit description reduced fault list test pattern fault simulator fault coverage tpg. Apr 16, 2020 software testing test coverage complete guide. The tessent scan and atpg course will drive the development of your skills and knowledge in scan and atpg design utilizing the tessent scan, tessent fastscan, and the dftvisualizer tools. Using automatic testpattern generation atpg techniques, you have the capability to test a much larger number of internal faults than with functional testing alone. Atpg detects and diagnoses errors by independently and exhaustively testing all forwarding entries, rewall rules, and any packet processing rules in the network. According to robert ruiz, senior marketing manager for test at synopsys, 16nm and 14nm designs are increasingly adopting finfet nodes. Dft compileratpg tool combo aids in dft electronic design.

To run fault simulation on nonatpg test vectors, make sure the simulator. So, now we know that code coverage is a measure of how much code is executed during testing, while test coverage is a measure of how much of the feature set is covered with tests. Software testing is an essential activity in the software development and maintenance life cycles. Synopsys testmax atpg is synopsys stateoftheart pattern generation solution that enables design teams to meet their test quality and cost goals with unprecedented speed. Code coverage is an option when you run test methods using test explorer. Automatic test pattern generation atpg is recommended in order to obtain high test coverage quickly. This document is for information and instruction purposes. In addition, the source editor shows you which code has been tested. Mentor graphics reserves the right to make changes in specifications and other information contained in this. This will help some percent of faults will be testable. Stmicroelectronics faces the challenges of increasing complexity and. Test coverage measures the amount of testing performed by a set of test cases. During atpg, on the input side, boundary scan chain can isolate the core from primary inputs.