Using SCAN Bridge as an IEEE 1149.31 protocol addressable, multi-drop, backplane test bus

National Semiconductor's SCAN Bridge is being used to provide an addressable, multi-drop, 1149.1-based backplane test bus. Its architecture is based upon defining two additional protocols to extend IEEE 1149.1 for use as a backplane test bus: an address protocol and a park protocol. These allow features such as the single, multicast, and broadcast address modes of P1149.5 to be included in the bridge.