Detecting an unstable input to an IC
AssigneeInternational Business Machines Corporation
InventorsThomas Buechner, Martin Eckert, Matthias Klein, Manfred Walz, Andreas Wagner, Gerhard Zilles
Life of this patent
Estimating the term…
Abstract
Additional circuitry is included in an input cell design structure for an integrated circuit to detect and report transitions on an input that was expected to be stable, and to store that event for later analysis. Two or more modified input cells may have their error indications daisy-chained together to minimize additional routing. The storage elements may be included in a scan chain to allow for isolation of which input had the unexpected transition.
Claims21
A method for detecting unstable inputs to an integrated circuit, the method comprising:
- receiving an input value on an external input of the integrated circuit, wherein said external input is communicatively coupled to an input cell of the integrated circuit;
- driving a first output trace from the input cell based on said input value;
- detecting a transition on said external input during a time period that said external input is expected to be stable;
- storing a value representing said transition into a storage element;
- and
- asserting an error output on a second output trace in response to said transition.
An integrated circuit comprising:
- a first external input;
- a trace in the integrated circuit configured to be driven based on an electrical level received at the first external input;
- a storage element capable of being set to a value selected from the group consisting of a first value and a second value;
- initialization circuitry configured to set the storage element to the first value before a time period that the external input is expected to be stable;
- transition detection circuitry configured to detect a transition on the first external input during said time period and set the storage element to the second value in response to said transition;
- and
- an error output trace configured to be driven based on the value set in the storage element.
A design structure tangibly embodied in a non-transitory machine readable medium for designing, simulating, manufacturing, or testing an integrated circuit, the design structure comprising:
- a trace configured to be driven based on an electrical level received at a first input;
- a storage element capable of being set to a value selected from the group consisting of a first value and a second value;
- initialization circuitry configured to set the storage element to the first value before a time period that the external input is expected to be stable;
- transition detection circuitry configured to detect a transition on the first input during said time period and set the storage element to the second value in response to said transition;
- and
- an error output trace configured to be driven based on the value set in the storage element.
Dependencies are inferred from the claim text.