International Business Machines Corporation

Raghu G GopalaKrishnaSetty

Mary Prilotski Kusko

James Douglas Warnock

Sridhar H Rangarajan

Venkatasreekanth Prudvi

Spencer K Millican

Balaji Upputuri

Ankit N Kagliwal

Purushotam Bheemanna

Pavan K Guntipalli

Kshitij Kulshreshtha

Embodiments include techniques for using circuit structures for resolving random testability, the techniques includes analyzing a logic structures of a circuit design, and identifying the logic structures of the circuit that are random resistant structures. The techniques also include replacing the logic structures with random testable structures, and performing a test of the circuit design.

Circuit structures to resolve random testability

A method for self-moderating bus arbitration for access to a common bus is provided. The method may include receiving, by a bus arbiter, a request from a master device, wherein the received request includes a priority value set by the master device. The method may also include identifying the priority value from the received transaction request. The method may then include determining an insertion point within a priority table based on comparing the identified priority value to a table entry priority value associated with each table entry within the priority table. The method may further include inserting a new entry into the priority table based on the determined insertion point. The method may also include identifying a highest priority entry within the priority table. The method may then include serving the identified highest priority entry.

Self-moderating bus arbitration architecture

A method includes receiving a circuit design comprising an input scan chain comprising a plurality of latches connected by one or more scan connections, dividing the plurality of latches into one or more clusters, determining a number of scan controls for each cluster, placing the determined scan controls in selected locations; and adjusting the scan connections based on the scan control location. A corresponding computer system and computer program product are also disclosed.

Adjusting scan connections based on scan control locations

A scan chain of an integrated circuit is disclosed, including a plurality of scannable storage elements and a control test point having a scan latch and an integrated clock gate (ICG) with clock, functional enable (FE) and scan enable (SE) inputs, and a gated clock output. The ICG may respond to an SE input active state, in a serial scan mode allowing the gated clock output to change. The ICG may also be operated in a scan capture mode, responding to an SE input inactive state, in which the gated clock output is inhibited from changing in response to a low FE input level. The ICG's gated clock output may be coupled to the scan latch clock input, which may hold its data output at a fixed level in response to ICG's gated clock output being inhibited from changing during the scan capture operation.

Control test point for timing stability during scan capture

A control test point (CTP) of an integrated circuit scan chain includes a scan latch and an integrated clock gate (ICG). The ICG includes clock, functional enable (FE) and scan enable (SE) inputs, and a gated clock output. The ICG can respond to an SE input active state, in a serial scan mode allowing the gated clock output to change. The ICG can also be operated in a scan capture mode, responding to an SE input inactive state, in which the gated clock output is inhibited from changing in response to a low FE input level. The ICG's gated clock output is coupled to the scan latch clock input, which holds its data output at a fixed level in response to ICG's gated clock output being inhibited from changing during the scan capture operation.

A method for creating an architecture to support Q-gating for launch-off-shift (LOS) scan testing using a plurality of flip-flops is provided. The method may include applying a common clock signal to each clock input of the plurality of flip-flops and applying a gated scan enable signal to each scan enable input of the plurality of flip-flops. The method may further include applying a global scan enable signal directly to each of a plurality of Q-gates corresponding to each of the plurality of flip-flops, wherein the global scan enable signal traverses a signal path that bypasses combinational logic located between any two flip-flops of the plurality of flip-flops.

Q-gating cell architecture to satiate the launch-off-shift (LOS) testing and an algorithm to identify best Q-gating candidates

A processor-implemented method for selective Q-gating flip-flops in a plurality of flip-flops contained in a design is provided. The method may include determining a maximum width, a maximum depth, and a maximum congestion value in the design and determining a relative width, a relative depth, and a relative congestion value for each of the plurality of flip-flops in the design. The method may further include determining grade values for each of the plurality of flip-flops in the design based on a ratio between the relative width, the relative depth and the relative congestion value, and the maximum width, the maximum depth, and the maximum congestion value, respectively and determining an overall summed value for each of the plurality of flip-flops. Then the method may sort the plurality of flip-flops based on the overall summed value for the plurality of flip-flops according to magnitude.

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Bengaluru, India

Raghu G GopalaKrishnaSetty