| 摘要 |
PURPOSE:To make the analysis easy at a trouble detection time, by storing the state on a bus in certain continuous cycles including idle cycles and reading out this stored information to use it for trouble analysis at the trouble detection time. CONSTITUTION:A bus log storage circuit BHR 15 connected to a bus 10 is provided. The circuit 15 incorporates a memory having a certain capacity and stores bit states of an address/data line, a command line, etc. on the bus 10 in the incorporated memory at intervals of every bus cycle time including idle cycles with respect to required information of these lines. Stored contents are rewritten in order from the oldest contents if they exceed a certain quantity of words, and a certain quantity of the latest information is always stored. Information of the data line, the command line, a unit ID line, and a control line are stored in individual words. Consequently, the contents of the circuit 15 are referred to at the time when a trouble is detected to make the analysis easy. |
