| 摘要 |
PROBLEM TO BE SOLVED: To provide a controller for not obstructing the outside by stopping/ permitting the operation of a communication control part by a protection means. SOLUTION: This controller is provided with the protection means for stopping/permitting the operation of the communication control part. Relating to the controller, a read/write protection means 8 is composed of a negative logic OR gate, a permission register and a NAND gate. Then, the read/write protection means 8 stops the entire access to the outside of a back plane bus controller 9 by reset signals and initialization signals when the initialization of power supply and restart, etc., is started. Then, at the point of time of normally ending the self diagnosis of hardware, the access to the outside of the back plane bus controller 9 is permitted by set signals. Thus, to a fault such as the runaway of a software at the time of the initialization start, the disturbance such as the closure of the internal bus of a back plane bus 6 and the other device is prevented.
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