Importance

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Abstract

A semiconductor memory (1) comprising a plurality of memory blocks (2 and 3) provided with a lot of memory cells, a data-input/output buffer (7), and first control means (11) for controlling the rewriting and reading of data for the memory cells is provided with first storage means (30) for designating part of the defective memory blocks and detection means (32) for detecting the access to a defective memory block designated by the first storage means in accordance with an address signal. In this case, when the detection means detects the access to a defective memory, the first control means inhibits the data rewrite operation for the instruction of the data rewrite operation and inhibits the data output operation of the data input/output buffer for the instruction of the data read operation. The inhibiting function makes it possible to provide a memory device having the compatibility with a non-defective semiconductor memory only by combining semiconductor memories having irremediable defects without fixing the levels of specific address input terminals so as to keep the defective memory blocks non-selective.

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First Claim