ADDRESS CONTROL METHOD OF EEPROM

摘要

PURPOSE: To improve the security by preventing EEPROM data from being forged. ;CONSTITUTION: When a control ROM area 24b where 4 process routine P for EEPROM rewriting is called from a user program area 24a through a subroutine, a jump to a control ROM area 24b is made through a jump table 24c once. When this jump table 24c is referred to, an offset value (y) stored in a register 30 composed of an EEPROM is added by an adder 31 to call the process routine P assigned to a fixed address even when an entry address (x) which is different, user by user, is assigned.;COPYRIGHT: (C)1995,JPO