| 摘要 |
PURPOSE:To facilitate confirming the normality of a scan path and pointing hardware having an abnormal position at the abnormality time by reading out code information through the scan path and discriminating read-out code information. CONSTITUTION:A control means 21 decodes a control command to output a control signal which sets code information to a flip flop group of a scan path 22. The means 21 decodes the control command to output a control signal by which the scan path 22 performs one-bit shift operation. Setting of code information and setting of the control command of the one-bit shift operation are repeated until information is outputted from all flip flops on the scan path 22; and if the scan path 22 is normal, data other than code information is set and left in a comparison data register 141 by a diagnostic processor. If the scan path 22 is abnormal, code information of hardware of maintenance and replacement having the abnormal position of the scan path 22 is left in the comparison data register 141. |
