Testing two-phase transition signaling based self-timed circuits in a synthesis environment

The problem of testing self-timed circuits generated by an automatic synthesis system is studied. Two-phase transition signaling is assumed and the circuits are targeted for an asynchronous macromodule based implementation. The partitioning of the circuits into control blocks, function blocks, and predicate (conditional) blocks, originally conceived for synthesis purposes, is found to be very elegant and appropriate for test generations. The problem of data dependent control flow is solved by introducing a new macromodule called SCANSELECT (SELECT with scan). Algorithms for test generation are based on the Petri-net like representation of the physical circuit. The techniques are illustrated on the high-level synthesis system called SHILPA being developed by the authors. An important contribution of the paper is the technique to test both datapath and control parts of self-timed circuits on a unified framework by adapting existing algorithms for testing synchronous circuits