Abstract: 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.

Abstract: Methods and systems are described to identify potential failures caused by metastability arising from signal propagation between asynchronous clock domains in integrated circuits with multiple operating modes, each mode allowing selected clocks to propagate. Typical integrated circuits have numerous operating modes, and hence numerous possible clock combinations, each combination causing different asynchronous clock-domain crossings, and hence different potential failures. Since verification for even one clock combination is time-consuming, explicitly enumerating and verifying all possible clock combinations is unviable. In practice very few clock combinations are verified, possibly missing failures.