| 摘要 |
PURPOSE:To surely protect the security of data by providing a non-volatile memory with an address signal selecting circuit which logically rotates or inverts n-bit address signals out of m-bit address signals (n<=m) to input them to an address decoder. CONSTITUTION:An address signal selecting circuit 4 is provided with registers R0 and R1, inverters 11A and 11B, and MOS transistors TRs 12 to 15 and selects address signals to an address decoder 2. Memory cells M0 to M3 can take all addresses 0 to 3 by combination of inversion and non-inversion of address signals A0 and A1. When only the register R0 is provided and the address signal A1 is directly inputted to an input 17 of the address decoder 2, the same result that the register R1 is set to '0' is obtained. Since addresses of memory cells M0 to M3 are determined by a user in this manner without being limited to a specific address, the security is protected. |
