| 摘要 |
PROBLEM TO BE SOLVED: To enhance secrecy of the stored content of a mask ROM by scrambling the address signal supplied from an external circuit. SOLUTION: A scramble circuit 27 is provided between an address buffer 25, a row decoder 21 and a column decoder 23, scrambling is executed with the scramble circuit 27 to the address signal supplied from an external circuit and only one memory cell 19 is selected from the memory cell array 17 depending on the scrambled address signal. |
