An apparatus enables a high quality test to be carried out within a short time, without forcing a severe design limitation on the designer and without an expensive tester. The apparatus includes a pattern generator built in an integrated circuit to generate pseudo random patterns as test patterns. A plurality of shift registers are configured with sequential circuit elements inside said integrated circuit. An automatic test pattern generating unit generates ATPG patterns. A pattern modifier modifies a portion, to which a predetermined value is required to be set in order to detect a fault, in said pseudo random patterns generated by said pattern generator, on a basis of said ATPG patterns, and inputs said modified pseudo random patterns to said shift registers.
The purpose of the invention is to determine an optimum initial value to be input to a test pattern generator in order to achieve efficient testing of an integrated circuit. To achieve this purpose, a minimum test length is obtained by performing a fault simulation and a reverse-order fault simulation using an arbitrarily given initial value; the next initial value that is likely to yield a test length shorter than the minimum test length is computed and a fault simulation is performed using the thus computed initial value; and the next initial value that is likely to yield a test length shorter than that test length is computed and a fault simulation is performed using the thus computed initial value. By repeating this process, an initial value that yields the shortest test length is obtained.
Disclosed below are representative embodiments of methods, apparatus, and systems for generating test patterns having an increased ability to detect untargeted defects. In one exemplary embodiment, for instance, one or more deterministic test values for testing targeted faults (e.g., stuck-at faults or bridging faults) in an integrated circuit design are determined. Additional test values that increase detectability of one or more untargeted defects during testing are determined. One or more test patterns are created that include at least a portion of the deterministic test values and at least a portion of the additional test values. Computer-readable media comprising computer-executable instructions for causing a computer to perform any of the disclosed methods or comprising test patterns generated by any of the disclosed embodiments are also disclosed.
A method for implementing test generation for systematic scan reconfiguration in an integrated circuit is presented. The method may comprise: defining at least one set of detectable faults; setting an SAS decoder configuration, the SAS decoder configuration including a don't-care bit; generating an ATPG pattern; and applying the ATPG pattern to one or more scan chain segments having a segment address associated with the SAS decoder configuration.
Methods and apparatus to test memories, such as, for example, caches of processors, are disclosed. In one aspect, an apparatus may include a pseudo random address generation unit, such as, for example, including a linear feedback shift register, to generate pseudo random memory addresses, and a deterministic data generation unit, such as, for example, including a state machine, to generate deterministic data to be written to the pseudo random memory addresses. Computer systems and other electronic systems including such apparatus are also disclosed.
