A method and a device are provided for protecting data stored in a ROM of a micoprogram control unit. Such data may take the form of a user program. To protect the data, predetermined code data is written into a predetermined address in the ROM. A code address inputted from outside the microprogram control...http://www.google.com.au/patents/US5313520?utm_source=gb-gplus-sharePatent US5313520 - Method and device for protecting data of ROM
