Memory content protection during scan dumps and memory dumps

Abstract

A method and apparatus for preventing the overwriting of memory contents during certain scan operations is disclosed. An integrated circuit (IC) may include a memory and a scan chain having a number of serially coupled scan elements. A number of the scan elements may be coupled to circuitry for inputting signals to or receiving signals output from the memory. An inhibit circuit may also be coupled to the circuitry for inputting signals to the memory. During scan shifting operations commensurate with a scan dump mode or a memory dump mode, the inhibit circuit may de-assert one or more control signals that otherwise enable access to the memory in order to prevent shifted data from overwriting the contents stored in the memory. The apparatus may also include a bypass unit coupled to a memory read port, which can be activated to prevent unauthorized access to protected data stored in the memory.