A Cascaded Multicasting Architecture for Test Data Compression

This paper proposes a cascaded multicasting scan (CMS) architecture with simple control logic and low hardware overhead for test data compression. Instead of specifying all the addresses of the scan chains that will receive the test data in each broadcast, CMS specifies only the address of the first scan chain using log2(n) control bits in each broadcast on an n-scan chain architecture. CMS relies on test pattern compatibility analysis to determine the scan chain order to minimize the number of broadcasts. Experimental results show that with a much smaller hardware overhead CMS achieves a compression effect comparable to that attained by previous work on multicasting scan. The runtime for synthesizing a CMS architecture is also much smaller than that used by previous work.