Cascaded broadcasting for test data compression

This paper presents a cascaded broadcast scheme for test data compression. The basic idea is to conduct a different number of broadcasts in a cumulative way to load each test pattern into scan chains. The broadcast scope can be dynamically reduced as a result of the compatibility analysis among scan chains so that broadcasts can proceed efficiently and each scan chain is guaranteed to receive correct test data. Compared with similar works using broadcasting scheme, this method is very simple and effective. Experimental results for the ISCAS´89 benchmark circuits have demonstrated that a significant compression effect can be achieved at the cost of a limited amount of selection signals and low hardware overhead.