| 摘要 |
A non-volatile semiconductor memory device comprises a plurality of memory cell units each of which includes a plurality of non-volatile memory cells capable of having data electrically rewritten; a storage unit; and an access inhibiting circuit. The storage unit stores therein the defect information of the memory cell unit not normally operating. The access inhibiting circuit judges the condition of the memory cell unit within the device according to the defect information stored in the storage unit. Access to the memory cell unit not normally operating is inhibited in accordance with the result of the judgement. Since the device can control the information of the memory cell unit not normally operating by itself, users of the device need not manage the defective memory cell unit. Consequently, the usability of the device is enhanced and the cost of a system mounting the device is curtailed. Particularly, it is effective for the non-volatile semiconductor memory device for file allowing the presence of inoperative memory cells.
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