| 摘要 |
PURPOSE:To avoid missing the information showing the stage under which a device is hung although the device is actually hung, by controlling the writing to a history memory in accordance with the result of comparison between the content of a latch group and the content of history data. CONSTITUTION:When a device is hung, the same plural statuses and commands are successively latched to a latch group 11. Then the content of the group 11 is identical with the content of a history buffer 13. As a result, the dissident signal delivered from a comparator 19 is set at logic ''0'' to inhibit the writing of the history data to a history memory 16. At the same time, the renewal of a history pointer 17 is also inhibited. Thus the information showing the stage under which the device is hung is preserved in the memory 16 in case the device is actually hung. |
