摘要:
Disclosed are representative embodiments of methods, apparatus, and systems for power aware test applications involving deterministic clustering of test cubes with conflicts. Embodiments of the disclosed technology can be used to generate low toggling parent patterns to reduce power consumption during testing an integrated circuit. The power consumption may be further reduced by generating low toggling control patterns.
摘要:
Disclosed are methods and devices for temporally compacting test response signatures of failed memory tests in a memory built-in self-test environment, to provide the ability to carry on memory built-in self-test operations even with the detection of multiple time related memory test failures. In some implementations of the invention, the compacted test response signatures are provided to an automated test equipment device along with memory location information. According to various implementations of the invention, an integrated circuit with embedded memory (204) and a memory BIST controller (206) also includes a linear feed-back structure (410) for use as a signature register that can temporally compact test response signatures from the embedded memory array during a test step of a memory test. In various implementations the integrated circuit may also include a failing words counter (211), a failing column indicator (213), and/or a failing row indicator (214) to collect memory location information for a failing test response.
摘要:
Methods and devices for using high-speed serial links for scan testing are disclosed. The methods can work with any scheme of scan data compression or with uncompressed scan testing. The protocol and hardware to support high speed data transfer reside on both the tester and the device under test. Control data may be transferred along with scan data or be partially generated on chip. Clock signals for testing may be generated on chip as well. In various implementations, the SerDes (Serializer/Deserializer) may be shared with other applications. The Aurora Protocol may be used to transport industry standard protocols. To compensate for effects of asynchronous operation of a conventional high-speed serial link, buffers may be used. The high-speed serial interface may use a data conversion block to drive test cores.
摘要:
A method and apparatus to compact test responses containing unknown values or multiple fault effects in a deterministic test environment. The proposed selective compactor employs a linear compactor with selection circuitry for selectively passing test responses to the compactor. In one embodiment, gating logic is controlled by a control register, a decoder, and flag registers. This circuitry, in conjunction with any conventional parallel test-response compaction scheme, allows control circuitry to selectively enable serial outputs of desired scan chains to be fed into a parallel compactor at a particular clock rate. A first flag register determines whether all, or only some, scan chain outputs are enabled and fed through the compactor. A second flag register determines if the scan chain selected by the selector register is enabled and all other scan chains are disabled, or the selected scan chain is disabled and all other scan chains are enabled. Other embodiments allow selective masking of a variable number of scan chain outputs.
摘要:
The test data compression scheme is based on deterministic vector clustering. Test cubes that feature many similar specified bits are merged into a parent pattern in the presence of conflicts. The parent pattern along with a control pattern and incremental patterns representing conflicting bits are encoded efficiently. A tri-modal decompressor may be used to decompress the test data.
摘要:
A system and method for a hybrid, variational, user-controlled, 3D mesh smoothing for orphaned shell meshes. The smoothing model is based on a variational combination of energy and equi-potential minimization theories. A variety of smoothing techniques for predicting a new location for the node-to-smooth are employed. Each node is moved according to a specific smoothing algorithm so as to keep element included angles, skew and distortion to a minimum. The variational smoother selection logic is based on nodal valency and element connectivity pattern of the node to smooth. Results show its consistency with both quadrilateral and quad-dominant meshes with a significant gain over conventional Laplacian schemes in terms of mesh quality, stability, user control and flexibility.
摘要:
A method for applying test patterns to scan chains in a circuit-under-test. The method includes providing a compressed test pattern of bits; decompressing the compressed test pattern into a decompressed test pattern of bits as the compressed test pattern is being provided; and applying the decompressed test pattern to scan chains of the circuit-under-test. The actions of providing the compressed test pattern, decompressing the compressed test pattern, and applying the decompressed pattern are performed synchronously at the same or different clock rates, depending on the way in which the decompressed bits are to be generated. A circuit that performs the decompression includes a decompressor such as a linear feedbackstate machine adapted to receive a compressed test pattern of bits. The decompressor decompresses the test pattern into a decompressed test pattern of bits as the compressed test pattern is being received. The circuit further includes scan chains for testing circuit logic, the scan chains coupled to the decompressor and adapted to receive the decompressed test pattern.
摘要:
A novel decompressor/PRPG on a microchip performs both pseudo-random test pattern generation and decompression of deterministic test patterns for a circuit-under-test on the chip. The decompressor/PRPG has two phases of operation. In a pseudo-random phase, the decompressor/PRPG generates pseudo-random test patterns that are applied to scan chains within the circuit-under test. In a deterministic phase, compressed deterministic test patterns from an external tester are applied to the decompressor/PRPG. The patterns are decompressed as they are clocked through the decompressor/PRPG into the scan chains. The decompressor/PRPG thus provides much better fault coverage than a simple PRPG, but without the cost of a complete set of fully-specified deterministic test patterns.
摘要:
Disclosed herein are exemplary embodiments of a so-called “X-press” test response compactor. Certain embodiments of the disclosed compactor comprise an overdrive section and scan chain selection logic. Certain embodiments of the disclosed technology offer compaction ratios on the order of 1000×. Exemplary embodiments of the disclosed compactor can maintain about the same coverage and about the same diagnostic resolution as that of conventional scan-based test scenarios. Some embodiments of a scan chain selection scheme can significantly reduce or entirely eliminate unknown states occurring in test responses that enter the compactor. Also disclosed herein are embodiments of on-chip comparator circuits and methods for generating control circuitry for masking selection circuits.
摘要:
A method for compressing test patterns to be applied to scan chains in a circuit under test. The method includes generating symbolic expressions that are associated with scan cells within the scan chains. The symbolic expressions are created by assigning variables to bits on external input channels supplied to the circuit under test. Using symbolic simulation, the variables are applied to a decompressor to obtain the symbolic expressions. A test cube is created using a deterministic pattern that assigns values to the scan cells to test faults within the integrated circuit. A set of equations is formulated by equating the assigned values in the test cube to the symbolic expressions associated with the corresponding scan cell. The equations are solved to obtain the compressed test pattern.