Microcomputer

Abstract

Abstract PURPOSE:To rewrite part of a ROM falsely by storing address data desiring to correct in the ROM into a nonvolatile memory, and executing a modified program when the data coincides with a program counter. CONSTITUTION:The address data and correction program data when a bug or partial correction is desired for the writing program of a program memory ROM 2 are written on an electrically writable nonvolatile memory EPROM 3. When the address data coincides with the output content of the program counter 1, corrected program data is outputted from the EPROM 3 instead of the program data to be corrected in the memory 2. And the corrected program data is selected with a selector 4, and is inputted to an instruction decoder 5. Therefore, the program rewritten falsely is decoded with the instruction decoder 5, and a corrected program can be executed.

Inventors

• 👤 Azuma Miyazawa
• 👤 東 宮沢
• 👤 Hisaaki Ishimaru
• 👤 寿明 石丸

Bibliographic Details