The present invention is directed to a method and apparatus for exposing pre-diffused IP blocks in a semiconductor device for prototyping based on hardware emulation. Addresses may be provided to multiplexers through configuration pins. The input ports of the multiplexers may be connected to interface pins of the pre-diffused IP blocks, and the output ports of the multiplexers may be connected to I/O pins which provide input and output to the semiconductor device. Through controlling the signals on the configuration pins and thus the outputs of multiplexers, any single pre-diffused IP blocks or any combination of the pre-diffused IP blocks in the semiconductor device may be exposed through corresponding I/O pins for prototyping.