| 摘要 |
PURPOSE:To directly refer the error status (abnormal status) or the like of an external circuit from a diagnosing device without passing a processor by switching an address line in a diagnosis interface in accordance with the state whether the processor is in the operating state or not. CONSTITUTION:The processor 1 is provided with the 1st circuit 5 for inhibiting the access of a processor peripheral circuit 2 from the processor 1 at the stopped state of the processor 1 and the 2nd circuit 6 for switching an address line 41 constituting a diagnosis interface 4 to two directions in accordance with the operating state of the processor 1 or its stopped status. At the stopped state of the processor 1, access from the processor 1 side to the peripheral circuit 2 is inhibited and the peripheral circuit 2 is accessed from the diagnosing device 3 side. Consequently, the peripheral circuit 2 such as an external register can be monitored by the diagnosing device 3 without using an ordinary state monitoring line. |
