| 摘要 |
PURPOSE:To provide a memory part within the MPU package connected to the program writing memory via an external wiring to give the pass word written from outside to the address converting part after storing the word, thus preventing an imitation of the system using this device. CONSTITUTION:The address converting part 2, which is connected between the address terminals A1-An of the processor part 1 and the address terminals A1'- An' of the package to make through or invert each bit, is provided within the package of the MPU which is used with a connection to the program writing memory via an external wiring, along with the processor part 1. Furthermore, the pass word memory part 3 of PROM is added to give the pass word commanding the above-mentioned through or inversion to the part 2. Thus the pass word is written from outside for storage. As a result, an imitation of the system using this MPU via an outsider since the contents of the pass word can never be detected at the side of terminals PW1-PWn after the pass word has been once written. |
