SEMICONDUCTOR MEMORY DEVICE WHICH PERFORM MASKING OF DATA WRITTEN IN PART OF AREA OF MEMORY CELL ARRAY WHEN WRITE OPERATION, AND ITS MASKING METHOD

摘要

PPROBLEM TO BE SOLVED: To provide a semiconductor memory device which performs masking of data written in a part of an area of a memory cell array, and its masking method. PSOLUTION: A semiconductor memory device is characterized in that it is provided with a memory cell array, a row address buffer, a column address buffer, a write protection circuit, and a column decoder. The write protection circuit is enabled or disabled responding to a first control signal, and when enabled, it outputs a masking control signal responding to a row address signal, a second strobe signal, and a second control signal. Responding to the masking control signal, the column decoder decodes the column address signal and enables or disables a column selection line corresponding to a column address signal decoded in the memory cell array. Thereby, the part area which is going to be protected by the memory cell array can be prevented from being written incorrect data. PCOPYRIGHT: (C)2006,JPO&NCIPI