Gate Delay Fault Test Generation for Non-Scan Circuits

This article presents a technique for the extension of delay fault test pattern generation to synchronous sequential circuits without making use of scan techniques. The technique relies on the coupling of TDgen, a robust combinational test pattern generator for delay faults, and SEMILET, a sequential test pattern generator for several static fault models. The approach uses a forward propagation-backward justification technique: The test pattern generation is started at the fault location, and after successful ¿local¿ test generation fault effect propagation is performed and finally a synchronising sequence to the required state is computed. The algorithm is complete for a robust gate delay fault model, which means that for every testable fault a test will be generated, assuming sufficient time. Experimental results for the ISCAS'89 benchmarks are presented in this pape

Hierarchical Delay Test Generation

Delay testing is used to detect timing errors in a digital circuit.In this paper, we report a tool called MODET forautomatic test generation for path delay faults in modular combinational circuits. Our technique usesprecomputed robust delay tests for individual modules to computerobust delay tests for the module-level circuit. We present alongest path theorem at the module level ofabstraction which specifies the requirements for path selectionduring delay testing. Based on this theorem, we propose a pathselection procedure in module-level circuits and report efficientalgorithms for delay test generation. MODET hasbeen tested against a number of hierarchical circuits with impressivespeedups in relation to gate-level test generation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43008/1/10836_2004_Article_134357.pd

Test Pattern Generator for Delay Faults

Rejestr MISR pobudzany słowami odczytywanymi z pamięci ROM jest jednym z ostatnio oferowanych rozwiązań problemu generacji par testowych dla uszkodzeń opóźnieniowych. W niniejszej pracy przedstawiono koncepcję zmniejszania liczby słów programujących oraz takiej modyfikacji grafu pracy ww. generatora par testowych, która pozwala na uzyskanie akceptowalnego czasu testowania przy stosunkowo wysokim współczynniku pokrycia uszkodzeń opóźnieniowych. W pracy przedstawiono rezultaty eksperymentów, w których wygenerowano opracowaną metodą pary testów dla benchmarków ISCAS'89.One of the recently proposed solutions to the problem generation of test pairs' patterns to target delay faults is a Multiple Input Signature Register (MISR). The paper proposes a method to minimize control words and to modify the operation diagram of the Test Pattern Generator (TPG) aiming at achieving acceptable test times while ensuring a very high coverage of delay faults. Experimental results are presented, in which the method of test pairs for benchmarks of the ISCAS'89 has been employed. These results confirm a high effectiveness of this method compared to other solutions

Modified Test Pattern Generator for Delay Faults

W artykule przedstawiono metodę generacji par testowych pobudzających uszkodzenia opóźnieniowe. Źródłem par testowych jest zmodyfikowany rejestr MISR. Modyfikacja rejestru MISR polega na podwojeniu jego długości. Dzięki temu udało się ograniczyć do jednego liczbę słów programujących, a tym samym zrealizować generator par testowych bez jakiejkolwiek pamięci. To spowodowało, że uzyskano podobne rezultaty jak dla generatora par testowych z pamięcią ROM, co jest główną zaletą przedstawionego generatora par testowych.A method of generating test pairs for delay faults is presented in the paper. A modified MISR register is the source of test pairs. Modification of this register consists in doubling its length (Fig. 3). Test pairs are only generated at a half of the MISR register chosen outputs. Doubling the MISR register makes it possible to generate all possible test pairs, which was proved in the papers [2, 3, 4]. The disadvantage of this solution is too large number of clock cycles. The test pairs for the delay faults include a quite number of don't cares. It enables a considerable reduction of the test pairs. Minimising the number of test pairs means a smaller number of clock cycles at a very high coverage factor of the test pairs. The process of merging the test pairs is shown on example. The number of programming words is limited to only one due to this modification. In consequence, it enables producing a generator of test pairs without ROM. There are presented the experimental results of generating the test pairs for benchmarks of ISCAS'89. The number of benchmark inputs was limited to 32. The results are similar to those for the generator of test pairs with ROM [1, 2, 4] (Fig. 1). The coverage factor is somewhere between 65% and 95% at the sequence length ranging from 160 to 300k clock cycles. The main advantage of this solution is the lack of ROM

Gate Delay Fault Test Generation for Non-Scan Circuits

This article presents a technique for the extension of delay fault test pattern generation to synchronous sequential circuits without making use of scan techniques. The technique relies on the coupling of TDgen, a robust combinational test pattern generator for delay faults, and SEMILET, a sequential test pattern generator for several static fault models. The approach uses a forward propagation-backward justification technique: The test pattern generation is started at the fault location, and after successful ¿local¿ test generation fault effect propagation is performed and finally a synchronising sequence to the required state is computed. The algorithm is complete for a robust gate delay fault model, which means that for every testable fault a test will be generated, assuming sufficient time. Experimental results for the ISCAS'89 benchmarks are presented in this pape