In this new approach, the input vector will be fully specified and the vector will be modified to detect the specified fault. Combinational test generationfor various classes of. The type of a gate denotes the boolean function implemented by this gate. Dalg and is often used as a baseline even in modern atpg algorithms. In an atpg, faults are modeled as stuckat faultssa1 or sa0. Combinational atpg l test generation tg methods lexhaustive methods lboolean equation lstructural analysis limplication graph l milestone structural atpg algorithms ldalgorithm roth 1967 l9valued dalgorithm cha 1978 lpodem goel 1981 lfan fujiwara 1983 lother advanced techniques. Atpg algorithms inject a fault into a circuit, and then use a variety of mech. Saab, atpg for combinational circuits on configurable hardware, ieee transactions on very large scale integration vlsi systems, vol. Roths dalgorithm dalg defined the calculus and algorithms for. Pdf in this paper, an efficient test pattern generation tpg algorithm for combinational circuits based on the boolean satisfiability method. The initial objective was selected to bring the atpg algorithm closer to propagating a d or d to a primary output. In sequential atpg algorithms, podem has been shown to be more e cient than other combinational algorithms.
Satbased atpg using multilevel compatible dontcares. Efcient satbased combinational atpg using multilevel don. Therefore, many different atpg methods have been developed to address combinational and sequential circuits. Nowadays fault detection algorithms are integrated into synthesis tools such as synopsis. Types of algorithms algorithm estimated speedup over d algorithm year dalg 1 1966 podem 7 1981 fan 23 1983 tops 292 1987 socrates 1574 atpg system 1988waicukauski et,al. The earliest algorithms extended the d algorithm roth 1966 for the iterativearraymodelkubo1968. An efficient atpg algorithm makes use of the functional and structural redundancies in the circuit to collapse all the faults into a small group of faults. Atpg algorithm which was created to overcome the inability of dalgorithm dalg to generate test vectors for circuits. The vertices of the graph are combinational logic elements with assigned numerical. The rest of the paper has been organized in the following. Combinational atpg l test generation tg methods lexhaustive methods lboolean equation lstructural analysis limplication graph l milestone structural atpg algorithms ld algorithm roth 1967 l9valued d algorithm cha 1978 lpodem goel 1981 lfan fujiwara 1983 lother advanced techniques. Pdf a framework of highquality transition fault atpg for.
Atpg algorithm was given, instead a simple heuristic was applied to generate test vectors. Various algorithms are designed to test stuckat faults. On enhancing deterministic sequential atpg khanh viet duong. 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. Difference between combinational and sequential circuit. Decision tree i,k,m k,m,n s i n no backtracking the main difference between the d algorithm and 9v algorithm is. Combinational atpg algorithm using the fourstate logic abstract. Based on the rtl atpg 8 as our basic algorithm, our atpg uses a 9valued algebra to ef. Guarantees all detectable faults in the combinational circuits are detected.
Pdf advanced atpg based on fan, testability measures and. Dec 07, 2019 we will first introduce the basics of. These algorithms together with the dynamic compaction algorithmare incorporated intoan advanced atpg system for combinationalcircuits, called mintest. Experimental results obtained using the new algorithms show that there is a 20% reduction in test set size, test data volume and test application time compared to a stateoftheart.
Many atpg algorithms generate tests by targeting a. Results are presented indicating that this new algorithm, termed topological search tops, is faster than existing algorithms and also rapidly identifies many redundant faults without search. On enhancing deterministic sequential atpg khanh viet duong thesis submitted to the faculty of the virginia polytechnic institute and state university in partial fulfillment of the requirements for the degree of master of science in electrical and computer engineering michael s. The input vector x1,0,0,1,1 sensitizes two paths emanating from h and terminating in f 2. As vlsi technology advances, integrated circuits are becoming larger and more complex, resulting in the need to develop more efficient methods of generating test sets. Podem expanded the binary decision tree only around. Test vector decomposition based static compaction algorithms for combinational circuits aiman h. The primitive dcubes of failure pdf model faults in a logic circuit, and can.
Automatic test pattern generation atpg 2 introduction almost all practical digital systems are sequential circuits. Testing of combinational circuit is crucial important to ensure high level of functionality. Vlsi design verification and test combo atpg ii cmpe 646 u m b c umbc 4 102104 u n i v e r s i t y o f l m a r y l a n d b a t i m o r e c o u n t y 1 9 6 6 dcalculus and d algorithm dcontains. Atpg algorithms, which can lead to extremely high test generation times. Atpg can fail to find a test for a particular fault in at least two cases.
Internal memory states state not known at the beginning of test. Automatic testpattern generation atpg for sequential circuits is an extremely expensive computational process, so that atpg algorithms working on complex circuits can spend many hours of cpu time and still obtain poor results in terms of fault coverage. Barnes and noble on campus has new, used and rental versions. A library is created by tokenizing the entire circuit. Atpg algorithm injects fault into circuit and then uses different techniques to activate fault into circuit. Replace 1 a 1 combinational circuits under the single stuck at fault model, and a new heuristic for estimating the minimum single stuck at fault test set size. Efcient satbased combinational atpg using multilevel dont. The hope fault simulation tool 7 is used to launch the atpg attack. Jan 14, 2019 the combinational atpg method allows testing the individual nodes or flipflops of the logic circuit without being concerned with the operation of the overall circuit. A framework of highquality transition fault atpg for scan circuits. Chapter 1 introduction virginia commonwealth university. Functional fault equivalence and diagnostic test generation in combinational logic circuits using conventional atpg andreas veneris1.
Jul 25, 2019 we will first introduce the basics of. Major combinational forward implication automatic test. In this work, we are designing automatic test pattern generator. It is the task of an atpg algorithm to generate a test for every fault in the circuit according to some fault model. First, the fault may be intrinsically undetectable, such that no patterns exist that can detect that particular fault. Introduce the basic concepts of atpg focus on a number of combinational and sequential atpg techniques. Mar 25, 2020 we will first introduce the basics of. Lecture 11alt advances in combinational atpg algorithms branch and bound search fan multiple backtrace, head lines 1983 tops dominators. D algorithm can handle arbitrary combinational circuits, with internal fanout structures main idea.
Design for testability strategies using fullpartial scan. Deterministic combinational atpg deterministic sequential atpg untestable fault identification. Origins of stuckorigins of stuckfaultsfaults testtest. Some e cient combination atpg algorithms, such as fan and top, are designed based on the podem algorithm. Suppose for the same fault we decide to observe the circuit response at f 2. The approach is based on automatically designing a circuit which implements the algorithm, an automatic test pattern generation atpg algorithm, specialized for the combinational circuit. Podem recognized that choosing primary inputs to set was important in e ciently realizing obtained a primary input assignment given. Osais king fahd university of petroleum and minerals testing systemonchips involves applying huge amounts of test data, which is stored in the tester memory and then transferred to the chip under test during test application.
However, it has been known for more than two decades that atpg is an npcomplete problem ibarra and sahni, ieee transactions on computers, vol. Combinational atpg l test generation tg methods lexhaustive methods lboolean equation lstructural analysis limplication graph l milestone structural atpg algorithms ld algorithm roth 1967 l9valued d algorithm cha 1978 lpodem goel 1981 lfan fujiwara. Abadir3 sep seyedi1 abstract fault equivalence is an essential concept in digital design with signi. Test generation for sequential circuit using podem algorithm. Research in automatic test pattern generation atpg on the other hand was primarily driven by specific applications in circuit testing. Atpg architecture 21 circuit description reduced fault list test pattern fault simulator fault coverage. Vlsi design verification and test combo atpg ii cmpe 646 1 10. This is the driver for using rpg followed by atpg for the hardtotest. Atpg algorithm which was created to overcome the inability of dalgorithm d alg to generate test vectors for circuits. A highly robust combinational test generation algorithm. Implementation of combinational automatic test pattern. If the wellknown stuckat fault model is assumed a test is obtained by finding a set of.
Vlsi test technology and reliability, 20092010 ce lab, tudelft 9 algorithm compl eteness an algorithm is complete if it ultimately can search entire binary decision tree, if needed, to generate a test completeness is important, otherwise atpg may not achieve the required fault coverage untestable fault no test for it even after entire tree. So that it becomes easy to generate test vectors for the circuit. This paper present the development of combinational atpg based on fan algorithm, testability measures and fault equivalence. These systems require that multiple passes be made through the atpg process in order to generate a test for a single fault.
Three of the best known algorithms for combinational atpg are the d algorithm. For the partialscan iscas 89 benchmark circuits, atpg models generated by our algorithms are 1 to 6 times. The test must initialize the circuit to a known state. Deterministic algorithms for atpg under leakage constraints. This occurs when there exists reconvergent fanouts with unequal inversion parities. Zerodelay for combinational and synchronous circuits. Itstartswith one copy of the combinational logic and sets it to timeframe 0. Vlsi design verification and test combo atpg i cmpe 646 u m b c umbc 93004 u n i v e r s i t y o f l m a r y l a n d b a t i m o r e c o u n t y 1 9 6 6 atpg algorithms since combinational fault simulation is on2, rpg and fault simulation is much more ef. Since the kernel circuit of the full scan design lsi is a combinational one, a combinational atpg algorithm can be applied to it and it can obtain high fault efficiency. Motivation automatic testpattern generation atpg for sequential circuits is an extremely expensive computational process, so that atpg algorithms working on complex circuits can spend many hours of cpu time and still obtain poor results in terms of fault coverage. After the introduction of the branch and bound search algorithm in podem, a number of.
Results the selection algorithms 4 are applied on the iscas 85 combinational circuits 6. Why is combinational atpg efficiently solvable for practical. Functional fault equivalence and diagnostic test generation. Because of the difficulty of the sequential atpg problem, the electronics. Test set compaction algorithms for combinational circuits. Vlsi design verification and test combo atpg ii cmpe 646 u m b c umbc 1 102104 u n i v e r s i t y o f l m a r y l a n d b a t i m o r e c o u n t y 1 9 6 6 atpg algorithms characteristics of the three main algorithms. Atpg algorithms for combinational circuits boolean difference singlepath sensitization dalgorithm podem redundancy identification problems of sequential circuit testing atpg approaches for sequential circuits timeframe expansion simulationbased approach scan summary outline.
Aug 29, 2019 we will first introduce the basics of. Our analysis focuses on the search and control mechanisms of each algorithm. Lecture 32combinational circuit test generation ch 7. Select propagation dpropagation dcubescubes to propagate fault effect to a circuit output dddrivedrive procedure 3. Mod09 lec01 introduction to automatic test pattern generation atpg and atpg algebras duration. Combinational atpg overview major atpg algorithms definitions dalgorithm roth 1966 dcubes bridging faults 9302014 2 logic gate function change faults podem goel 1981 xpathcheck backtracing summary forward implication results in logic gate inputs that are significantly labeled so that. It all relies heavily on automatic test pattern generation atpg procedures which are notoriously very performancedemanding even for combinational circuits. Jan 30, 2012 types of algorithms algorithm estimated speedup over dalgorithm year dalg 1 1966 podem 7 1981 fan 23 1983 tops 292 1987 socrates 1574 atpg system 1988waicukauski et,al. Sequential circuit atpg using combinational algorithms. Even a simple stuckat fault requires a sequence of vectors for detection in a sequential circuit. Three of the best known algorithms for combinational. Empirical observation shows that practically encountered instances of combinational atpg are efficiently solvable.
Algorithms computers and calculators alb ert nijenh uis and herb ert s. Previous lecture vlsi test technology and reliability. The approach is based on the redundancy addition and removal algorithm, which is based on automatic test pattern generation atpg techniques, and improves it using symbolic techniques based on bdds. Atpg basics s algorithms and representations s structural vs. Hardware abstractin this paper, a new approach for generating test vectors that detects faults in combinational circuits is introduced. The algorithms as presented does not implement backtracking. Chapter 04 atpg slides 100306 university of cincinnati. The rst class consists of structural methods which per. Combinational automatic test pattern generation atpg. Combinational logic circuits using conventional atpg andreas veneris1. Efficient transition fault atpg algorithms based on stuck.
A cube a dcontains cube b if the set of a cube vertices contains is a superset of the b cube vertices. A topological search algorithm for atpg proceedings of. Podem recognized that choosing primary inputs to set was important in e ciently realizing obtained a primary input assignment given the initial objective. As density of digital circuit increases rapidly day by day these increases cost and time to test a particular combinational circuit for testing such circuit we need high quality test vector pattern with minimum number of input combination.
Atpg for combinational circuits on configurable core. Many atpg algorithms generate tests by targeting a single fault and finding an input. Combinational automatic test pattern generation atpg 1. Pdf implementation of compaction algorithm for atpg generated. Existing atpg techniques for testing single stuckat faults in combinational circuits fall under three classes. A new algorithm is proposed that uses the smaller search space and the improved ordering for node assignments based on a topological analysis of the circuit. Automatic testautomatic test pattern pattern generation algorithms.
The atpg then translates the test environment into the systemlevel test vectors by plugging the precomputed test vectors into it. Therefore, any excessive runtimes will be multiplied by this process and achieving fast combinational atpg becomes even more. Sequential circuit atpg using combinational algorithms article in ieee transactions on computeraided design of integrated circuits and systems 248. Second, most sequential atpg techniques are based on combinational atpg algorithms 9,10. Module 6 combinational circuit testing tu delft opencourseware. View notes lec11a from elec 7250 at auburn university. Their testing is more complex than that of combinational circuits, due to two reasons.
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