Abstract: An apparatus for time aligning data acquired by one test instrument with corresponding data acquired by another test instrument is disclosed. A set of binary codes, representative of a set of instructions executed by a microprocessor disposed within a user's prototype circuit, are acquired by said one test instrument. With the acquisition of each of said binary codes, a count is developed in a counter indicative of each said acquisition. A multitude of binary data is acquired, independently of the acquisition of the set of binary codes, by said another test instrument, the multitude of binary data being representative of the functions performed by a set of components present within said user's prototype circuit. The binary codes acquired by said one test instrument and the binary data acquired by said another test instrument each have associated therewith a count developed from said counter.