METHOD AND DEVICE FOR REWRITING DATA OF PROGRAMMABLE ROM

摘要

PROBLEM TO BE SOLVED: To make it possible to rewrite the data of a large scale programmable ROM without increasing the capacity of a memory on a sub-substrate. SOLUTION: The data of the programmable ROM in a data rewriting device having a main substrate provided with an MPU and a RAM, and the sub- substrate provided with an MPU for controlling communication with a host computer and the programmable ROM storing control programs to be executed by the MPU are rewritten. The MPU of the sub-substrate stores an inputted rewriting program in a RAM directly or through the MPU of the main substrate and writes the rewriting program stored in the RAM in the programmable ROM directly or through the MPU of the main substrate.