A programmable circuit, such as a field programmable gate array, and a dedicated device, such as an ASIC type device, are coupled together with an antifuse based interface on a single integrated circuit. A configurable non-volatile memory that communicates with the dedicated device is also located on the integrated circuit. The platform for the programmable circuit is one half of an existing programmable circuit, which eliminates the need to engineer the programmable circuit. The programmable circuit includes a clock network that receives clock signals from clock terminals as well as from a clock network in the dedicated device. The interface between the dedicated device and programmable circuit includes a number of conductors with buffers with testing circuitry. The testing circuitry includes a PMOS test transistor and a NMOS test transistor which permits testing of the buffers without programming the antifuses coupled to the conductors. The input/output terminals around the periphery and in the interface between the programmable circuit and dedicated device are tested using JTAG registers. The path of the test signal through the JTAG registers is selectable to pass around the periphery of both the programmable and dedicated devices or through the interface and around the periphery of only one of the programmable and dedicated devices.