| 摘要 |
PURPOSE:To quickly repair the fault of the ROM of a ROM device to reduce the process down time of the ROM device by utilizing a remote maintenance circuit which makes data transfer with a center at a remote place and adding simple hardware. CONSTITUTION:When it becomes clear that a bug exists in the firmware stored in ROMs 31-3n, a maintenance attendant operates a terminal device 7 at a center and transfers repairing data containing a parity and the number information of a faulty chip storing the part of firmware bug to a processor unit 8 through a remote maintenance circuit 6. A CPU 5 makes the sent number of a faulty chip to be stored in a ROM select register 21 and sets the output level of the ROM select register 21 corresponding to the faulty ROM at 'L' level. As a result of the above-mentioned operations, the faulty ROM is set to a disabled state. When an address within the address range held by the faulty ROM is outputted to an address bus 100 thereafter, the RAM 11 of a substituting data section is set to an enabled state. |
