Non-volatile semiconductor memory device having an area responsive to writing allowance signal

摘要

A non-volatile semiconductor memory device comprises an area in which only one rewriting is possible and an area in which rewriting is possible repeatedly. A control circuit generates a high voltage from a boosting circuit and operates a writing circuit to write data in the rewritable area whose address designated by an address register/decoder. The control circuit allows writing of data into the area in which only one rewriting is possible by the writing circuit in response to an external signal. Therefore, even if the writing mode is set influenced by the unstable state of the power supply, destruction of the data in the area in which only one rewriting is possible can be prevented.