CONTROL SYSTEM CAPABLE OF PROTECTING EXTERNAL PROGRAM CODE

摘要

PURPOSE: A control system capable of protecting an external program code is provided to prevent a data drain of an external ROM using an address encryption key and a multiple encryption key. CONSTITUTION: An external ROM(800) encodes/stores a program code. A micro controller(700) reads a program stored in the external ROM(800) and controls a system using the program. A multiple encryption analysis unit(710) analyzes/converts an encryption program code being transmitted from the external ROM(800) into the original program code capable of being used in the micro controller(700) using encryption information. An external ROM interface(720) transmits a program code being transmitted from in the multiple encryption analysis unit(710). A command register(730) stores a program code being transmitted from an internal code bus. A program counter(740) includes position information of a program code to be read in the external ROM(800) and outputs an address signal(Add(15:0)). An address encryption unit(750) encodes the address signal(Add(15:0)) being transmitted in the program counter(740) for an encryption of an address and outputs an encoded address signal(Add_enc(15:0)).