METHOD FOR IMPROVEMENT OF OBSERVABILITY OF INTERNAL SIGNAL IN VLSI CHIP

摘要

PROBLEM TO BE SOLVED: To observe a behavior of an important electrical signal on a VLSI chip at each cycle without interrupting an ordinary operation. SOLUTION: An improved circuit and an improved method for capturing and observing an internal signal on an integrated circuit are provided. The internal signal is sent to a multiplexer used to select an ordinary operating signal or a debugging signal. A counter creates an address used to store the selected signal into an on-chip RAM. A multiplexer on the other side selects either an ordinary operating address or an address created by the counter. An output of the multiplexer on the other side provides an address of the on- chip RAM. After the selected signal has been stored in the on-chip RAM, a BIST engine then reads out the selected signal so as to be evaluated. COPYRIGHT: (C)2004,JPO