On multiplexed signal tracing for post-silicon debug

Abstract

Trace-based debug solutions facilitate to eliminate design errors escaped from pre-silicon verification and have gained wide acceptance in the industry. Existing techniques typically trace the same set of signals throughout each debug run, which is not quite effective for catching design errors. In this work, we propose a multiplexed signal tracing strategy that is able to significantly increase debuggability of the circuit. That is, we divide the tracing procedure in each debug run into a few periods and trace different sets of signals in each period. A novel trace signal grouping algorithm is presented to maximize the probability of catching the propagated evidences from design errors, considering the trace interconnection fabric design constraints. Experimental results on benchmark circuits demonstrate the effectiveness of proposed solution.