| 摘要 |
PURPOSE:To prevent the service lowering in case an autonomous scanner becomes inactive, by securing a reading of the read data given from a circuit to be scanned through a scanning read data line for both autonomous scanner and a processor. CONSTITUTION:Both driving and reading are secured by not only an input/output control device IOC but a processor CPU via an input/output bus for both scan address bus and read data bus which scan and read the circuits A1-An to be scanned of an autonomous scanner SCN. Thus a selection is possible between addition and an addition of the scanner SCN in accordance with the scale of system. In case the scanner SCN becomes inactive, the processor takes the place of the scanner to prevent the service lowering. |
