RTL level trace signal selection and coverage estimation during post-silicon validation

Trace buffers play a crucial role in curbing the obstacle of limited observability of internal states for error localization during post-silicon stage. Given the constraint of area over-head, selecting appropriate signals which are to be stored in the trace buffers is of paramount importance for the overall success of this observability enhancement mechanism. This paper proposes a register-transfer level trace signal selection methodology which uses assertions generated during pre-silicon design verification. The enlarged quantity of restored signal states in conjunction with the traced states help to estimate the coverage of particular events during post-silicon validation; thus, acting as a suitable alternative to synthesizing coverage monitors. Experimental results on opencore benchmark circuits indicate that the proposed methodology performs better than existing trace signal selection techniques, which focus on maximization of restoration of untraced signals from the traced ones.