Partial scan with preselected scan signals

This paper deals with partial scan approaches that select scan signals obli vious to the availability of flip-flops (FFs). Such approaches can greatly reduce the number of scan signals since maximum freedom is presented when s electing signals. However, to actually scan the selected signals, one must make them drive FFs. We study the problem of replicating and retiming a cir cuit to make a set of scan signals drive FFs while preserving the set of cy cles broken by the signals. We present a framework for solving the problem. Based on the framework, we present an efficient algorithm which also minim izes the amount of logic replication.