| 摘要 |
<p>PURPOSE:To execute a loop back test without being affected by the abnormality of a clock supplied from the outside by providing a loop back select part, loop back control part, loop back monitor part and internal clock generation part. CONSTITUTION:A clock monitor part 3 monitors the abnormality of the external clock supplied from the outside for operating a loop back select part 1 and a device to be tested. When any abnormality is detected, the clock supplied to the loop back select part 1 and the device to be tested is automatically switched to an internal clock generated by an internal clock generation part 2 by a loop back control part 4. Thus, without requiring any complicated operations, the loop back test can be executed without being affected by the abnormality of the clock supplied from the outside.</p> |
