SEMICONDUCTOR INTEGRATED CIRCUIT AND ITS TEST METHOD

摘要

PURPOSE: To perform a scan test without lowering security. CONSTITUTION: This circuit is constituted so that a flip-flop constituting a scan chain is reset when the scan test is started or finished by an edge of a mode signal for switching between an ordinary operation and the scan test. An internal storage means can not be accessed at the scan test time. A dummy flip-flop operating only at the scan test time is connected to the scan chain, and shift-out by the scan chain can not be performed at the ordinary operation time.