| 摘要 |
PURPOSE:To improve the confidentiality, by selecting a signal in response to a memory selection signal corresponding to a key code, performing a specific operation processing for the memory content and obtaining the key code. CONSTITUTION:Memories 1k, 2k have different memory content, a memory selection circuit 3 responds to memory selection signals M1, M2, selects the storage content and outputs them at output terminals MA-MD. An operation circuit 4 performs a specified operation processing for a selected memory output to obtain a normal key code, which is set to a key code register 5. That is, even if a decoder is set to an operating state, because the normal key code is not inputted, the decode circuit generates a memory selection signal and a read signal from a reception signal, selects the storage content of the corresponding memory, processes it at the circuit 4 to obtain the normal key code, which is set to the register 5 and applied to a decoder circuit. |
