MASK PROGRAMMABLE MICROPROCESSOR

摘要

PURPOSE: To provide a patch implementation module used for correcting a program error found in a ROM by addressing a different memory instead of a read only memory in a program counter and substituting a different program part for an erroneous program part. CONSTITUTION: The patch implementation module is provided with a first address register 42 provided with the address of the ROM 16 present immediately before the first address of the program part including an error, a second address register 44 provided with the first address of the different program part inputted to a RAM 18 relating to this microprocessor from a nonvolatile memory for instance for correcting the error and a comparator 46 for responding to the program counter 30 reaching the address of the first register 42 and loading the address of the second register 44 to the program counter 30.