| 摘要 |
PURPOSE:To read data out of an optional address of a main memory of a system of the remote side by obtaining only an answer by a central processing unit at the remote side of a direct memory access data transfer system. CONSTITUTION:When a register access of a data transfer device of the remote side arrives at a connection control circuit 11 via a bus control circuit 10, the circuit 11 drives an answer time monitoring circuit 12 to monitor the answer sent from the data transfer device of the remote side for a prescribed period of time. When an answer to the register access is given from the data transfer device of the remote side via an input/output interface 14, the circuit 11 resets the circuit 12. If no answer is given for a fixed period of time, the circuit 12 releases its own system bus. Thus it is possible to read out the contents of a memory of the system of the remote side despite of a fault of a central processing unit of the remote side. |
