SEMICONDUCTOR MEMORY DEVICE

摘要

A semiconductor memory device which is capable of selectively performing different functions has a chip having a nonvolatile memory capable of rewriting stored data, and a mode switcher disposed on the chip for irreversibly inhibiting data from being written in the nonvolatile memory upon elapse of a preset period of time from a time when a power supply of the semiconductor memory device is turned on if a predetermined signal is not supplied from outside of the chip within the preset period of time.