MEMORY FAULT DIAGNOSTIC DEVICE AND MEMORY FAULT DIAGNOSTIC METHOD

PROBLEM TO BE SOLVED: To provide a memory fault diagnostic device and a memory fault diagnostic method that can diagnose a fault of a memory in a minimum time by using an interval time after application execution within a preset control period, and minimize the fault diagnostic time of all the memory in an area to be diagnosed.SOLUTION: The area of a memory includes a diagnostic area 41 and a non-diagnostic area 42, the diagnostic area is divided into a plurality of Row areas which do not overlap each other, and each Row area is further divided into a plurality of Cell areas which do not overlap each other. A memory fault diagnostic method includes taking a diagnosis in two layers of an in-Row-area diagnostic step of making a diagnosis between Cell areas of all combinations with one cell area in a Row area and an inter-Row-area diagnostic step of making a diagnosis between Row areas of all combinations with one combination of Row areas in the diagnostic area, the Row areas being so sized that an in-Row-area diagnostic time is equal to an inter-Row-area diagnostic time.