Mutual Exclusion Sizing for Hoi Polloi

Granting access to a shared self-timed resource requires a mutual exclusion circuit to resolve contention. All such circuits contain cross-coupled logic gates to decide contested cases on a first-come-first-served basis. An end-of-metastability detector grants a decision only after metastability, if any, ends. This brief contrasts two previously published mutual exclusion designs and offers previously unavailable guides to achieving least uncontested grant delay for each design. The faster design integrates its cross-coupled gates and end-of-metastability detector into a single stage. The slower design pays a time penalty by isolating these two functions in separate sequential logic stages.