Hierarchically accessing 1149.1 applications in a system environment

This paper presents a novel connection method that enables in 1149.1 test bus controller to hierarchically access and test 1149.1 circuits, independent of where the circuit exists within in an electronic system. The advantage of this approach is that it enables the 1149.1 test bus to be used hierarchically as a system level test bus, instead of only as a board level test bus