A unified DFT architecture for use with IEEE 1149.1 and VSIA/IEEE P1500 compliant test access controllers

This paper discusses some of the critical issues that may prevent IEEE P1500 from becoming an acceptable standard and offers some suggestions for their solution. In particular, the inadequacy of the proposed P1500 and the VSIA solutions in handling hierarchical implementations is addressed. Support for hierarchical implementations is seen as an essential feature in a test access methodology that is intended for use in System on a Chip (SoC) designs. The author is actively pursuing some of these solutions through the working groups.