PURPOSE: To identify an architecture with an event to be tested substantially by providing a test circuit, a comparison circuit having an internal memory for comparing an input data with a stored data and generating a matching signal in response to the comparison, and a. circuit for controlling the test circuit in response to the matching signal.

CONSTITUTION: An event identification cell 24a, b having an internal memory for detecting an identification event produces a signal indicative of the moment of time of matching which is then interpreted by an event identification module 22. The module 22 may comprises test cell registers 14, 16 and a test memory 28 and provides a timing required for rising a test logic in the circuit during normal system operation and several protocols which can be built in the circuit in order to bring about a control.