| 摘要 |
PURPOSE:To detect the occurrence of a real fault while internal diagnosis is being performed by a host device and to confirm the normalcy of fault notification even for a CPU reset fault by masking the fault notification to the host device when the internal diagnosis is rendered, and storing a fault to reset the CPU of a device when it occurs. CONSTITUTION:The CPU 11, when receiving an internal diagnosis instruction from the host device 2, masks the notification of the fault to the host device by operating a host notification masking circuit 16 or 17, then conforms the notification of the fault to the CPU 11 by operating a pseudo fault generation circuit 12 or 13. Also, when the fault to reset the CPU 11 occurs, the CPU 11 gives an operation instruction to the host notification circuit 17 before reset, and the reset of the CPU 11 is stored in the host notification circuit 17 by generating a pseudo fault for the internal diagnosis. The CPU 11 reads out whether or not the operation instruction of the host notification masking circuit 17 is executed after reset, and continues the internal diagnosis by judging that the pseudo fault to reset the CPU 11 is generated by the internal diagnosis when the operation instruction is executed. |
