SCAN VECTOR SUPPORT FOR EVENT BASED TEST SYSTEM

摘要

An event based test system which can generate scan vectors for testing a semiconductor device of scan design without requiring a large amount of scan memory. The test system includes an event memory (20) for storing timing data and event type data of each event where the timing data is expressed by a plurality "log2N" of data bits for defining one test vector, an event generator (24) for generating an event with use of the timing data and the event type data from the event memory, and a mode change circuit provided between the event memory and the event generator for changing signal paths between a normal mode for generating the test vectors and a scan mode for generating the scan vectors by detecting the scan mode when the event type data from the event memory indicating a predetermined word. In the test system, each bit of the plurality Log2N" of data bits in the event memory defines 2N scan vectors, and 2N data bits are provided to the event generator in a series fashion, thereby producing the 2N scan vectors at each access of the event memory.