Abstract: An integrated circuit includes a plurality of logic function circuits disposed on the integrated circuit and interconnected by metal interconnect lines to form a logic network. A plurality of configurable logic function circuits is also disposed on the integrated circuit, each configurable logic function circuit being disposed on a respective area on the integrated circuit and not interconnected by the metal interconnect lines to form the logic network.

Abstract: A bus holder for coupling to an integrated circuit bus driven by a plurality of tri-state devices. The bus holder has a bidirectional port and first and second test ports. Logic circuitry coupled between the respective ports is configured such that application of a logic 0 to the first test port causes the bidirectional port to drive whatever logic value is applied to that port; application of a logic 1 to the first test port and application of a logic 0 to the second test port pulls the bidirectional port down to a logic 0; and, application of a logic 1 to both the first and second test ports pulls the bidirectional port up to a logic 1.