Real Intent, Inc.

Sanjeev Mahajan

Pranav N Ashar

Prakash Narain

Vishnu Vimjam

Ian Andrew Guyler

Oren Katzir

Integrated circuit failures caused by metastability related to assertion of asynchronous resets frequently escape detection before fabrication, causing design respins and severe economic loss. The numerous reset signals, flip-flops and complex logical interactions inherent in an integrated circuit cause an analysis for reset-metastability failures to be extremely noisy, reporting an unmanageable number of false failures and making early removal of failures impractical. Said noisy reporting arises because many flip-flops where reset-metastability manifests do not necessarily cause overall failure. An effective analysis of reset-metastability failures must identify all potential failures, but also must only report true failure potential. The present invention maximizes noise reduction by applying special conditions to identify flip-flops manifesting reset-metastability without causing integrated circuit failure, which can thereby be deemed safe. By reporting only true failure potential, the present invention enables efficient, robust and error-free removal of reset-related failures from an integrated circuit prior to fabrication.

Methods for identifying integrated circuit failures caused by reset-domain interactions

Methods and systems are described to augment gate-level simulation with the ability to efficiently detect and correct X-pessimism on-the-fly. Using static Boolean analysis, gates are identified in the simulated hardware where there is potential for the simulator to propagate an X while the actual hardware propagates a 1 or 0, i.e. gates where X-pessimism potentially occurs. Data regarding potentially pessimistic gates is utilized in real time during simulation to determine actual pessimism at the gate and to correct it when it happens. Whereas the understanding of X-pessimism and the method of augmenting simulation with attributes to correct X-pessimism in simulation on-the-fly is known in the public domain preceding known patents, various methods have been proposed recently to make on-the-fly X-pessimism correction more efficient for large ICs. The methods and systems described in the present invention, achieve new levels of performance and scalability of X-pessimism detection and correction.

Growing community of inventors

Mountain View, CA, United States of America

Sanjeev Mahajan