Siemens Industry Software Gmbh

Mentor Graphics Corporation

Sylwester Milewski

Janusz Rajski

Jerzy Tyszer

Yu Jane Huang

Nilanjan Mukherjee

Grzegorz Mrugalski

Jedrzej Solecki

Justyna Zawada

Yu Huang

The operational mode information and the hold-toggle pattern for a flexible isometric test compression system may be determined based on the plurality of test cubes generated for a subset of the targeted faults, the predetermined size and toggle rate for the hold-toggle pattern, and the predetermined maximum number of device inputs for full-toggle scan chains. The operational mode information comprising information of the full-toggle scan chains may be determined based on reduced toggle ranges first and the hold-toggle pattern may then be determined using a relaxation method. Alternatively, the hold-toggle pattern and the full-toggle scan chains may be determined incrementally together.

Isometric control data generation for test compression

A system for testing a circuit comprises scan chains, a controller, and hold-toggle circuitry. The hold-toggle circuitry is configured to allow, according to a control signal generated by the controller, some scan chains in the scan chains to operate in a full-toggle mode and some other scan chains in the scan chains to operate in a hold-toggle mode when a test pattern is being shifted into the scan chains. The control signal also contains information of a hold-toggle pattern for the scan chains operating in the hold-toggle mode. The hold-toggle pattern repeats multiple times when the test pattern is being shifted into the scan chains.

Flexible isometric decompressor architecture for test compression

Constant-output-value gates and buffer gates are determined for gates in a circuit design based on a hold-toggle pattern. The hold-toggle pattern determines in which shift clock cycles in a segment of consecutive shift clock cycles one or more scan chains receive bits based on corresponding bits of a test pattern or same bits as bits of previous shift clock cycles during a shift operation. Activation probabilities and observation probabilities are then determined for circuit nodes of the circuit design based at least in part on the constant-output-value gates and the buffer gates. Finally, test patterns are generated based on the activation probabilities and the observation probabilities.

Test generation using testability-based guidance

Various aspects of the disclosed technology relate to using capture-per-cycle test points to reduce test application time. A scan-based testing system includes a plurality of regular scan chains and one or more capture-per-cycle scan chains on which scan cells capture and compact test responses at predetermined observation points per shift clock cycle.

Test application time reduction using capture-per-cycle test points

Aspects of the disclosed technology relate to low power testing. A low power test circuit comprises a test stimulus source, a controller; and a grouping and selection unit. The grouping and selection unit has inputs coupled to the test stimulus source and the controller and has outputs coupled to a plurality of scan chains. The grouping and selection unit is configured to dynamically group scan chains in the plurality of scan chains into a plurality of scan chain groups and to selectively output either original test pattern values generated by the test stimulus source or a constant value to each scan chain group in the plurality of scan chain groups based on control signals received from the controller.

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Nowe Miasto Lubawskie, Poland

Sylwester Milewski