Microcomputer with memory content protective

Abstract

Abstract PURPOSE:To surely prevent the readout of data by the third party, while eraser is not performed by itself, by constituting a readout inhibiting mechanism of a read only memory with more than one writable read only memories. CONSTITUTION:A readout inhibiting mechanism inhibiting the operation of a data damp mechanism outputting the content of a read only memory is constituted by using more than one writable read only memories. for example, a read only memory ROM2 and a damp enable flag (DE)3 for readout inhibiting mechanism constitute a memory erasable with the irradiation of ultraviolet rays and they are close arranged. When a damp instruction is inputted, the damp output of the ROM2 is transmitted to a sense amplifier 6, an AND gate 7, and an output buffer 8 with a central processing unit 4 and when the damp inhibiting instruction is inputted, the transmission of damp output is stopped with the DE3.

Inventors

• 👤 Tetsuo Suzuki
• 👤 哲雄 鈴木

Bibliographic Details