| 摘要 |
PURPOSE:To prevent a program from being copied or decoded by forming a means enabling to set up address information previously, and at the start of operation, regarding an address set up by the means as a starting address to read out the contents of a memory and actuate a microcomputer. CONSTITUTION:When electric power is supplied to the one-chip microcomputer 1, the set value of an address information switch 2 is set up in a program counter 3. Only at the start of operation connecting the power supply to the computer 1, the gate 2-1 is made effective, and after the start of the operation, the computer 1 operates as a normal one-chip computer. The set value of the switch 2 is set up at the production of the computer 1 or at the time of utilization on the basis of its structure. Since the starting address of the program stored in a ROM4 can be set up to an optional value by the switch 2, the contents of the ROM4 can be prevented from copying or decoding due to reading-out of the contents. |
