Setup concepts -- Verdi ! Verdi

http://blog.csdn.net/naclkcl9/archive/2010/03/28/5425936.aspx

  2） 准确找出active X源

         • Stop at black box output signal (ON)
         • Stop at fanin that is X but no transition in its last cycle (ON)  －－－－－找出从此向前来源是固定的X（activeX）

         • Snap to value change and continue (OFF)