Test generation for hybrid iterative logic arrays

The test generation problem for hybrid iterative logic arrays (ILAs) which are constructed from ILAs of different types of cells by interconnecting them along their boundaries to realize a complex combinational function is discussed. The test generation problem for hybrid ILAs is complicated by the presence of different types of cell functions that affect test controllability and observability in different ways. For an array to be testable with a fixed number of test vectors irrespective of its size (C-testable), each of the individual constituent ILAs must satisfy certain rigid conditions that make test generation a difficult task. A graphical model is presented for test computation, and it is shown how this model can be used very effectively to generate efficient tests sets for hybrid ILAs