Using time resolved light emission from VLSI circuit devices for navigation on complex systems

A system and method for determining the location of a particular device on an integrated circuit chip is described. The system and method utilize apparatus for detecting the emission of light during switching events of devices in the circuit during the circuit\'s processing of an input calculated to actuate the device whose location is desired. Light emissions from the circuit can be temporally and spatially indexed so as to allow deduction, in combination with the a priori knowledge of the logical operation of the circuit, of the location of the desired element. In another embodiment of the invention, a series of images of the circuit can be accumulated, representing the circuit\'s response to a series of different input signals, each input signal being designed to result in the switching of the desired element. The series of images can be compared to determine the location of the desired element. Also in accordance with the invention, the elements to be located can be either actual functional circuit elements, or fiducials added to the chip for test purposes.