Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.