| 摘要 |
<p>PURPOSE:To easily detect a breakdown or to easily diagnose an operation by a method wherein a nonvolatile memory element which is written by a level of a power-supply voltage is installed and a changeover between a test mode and a normal mode is set by its memory state. CONSTITUTION:A mode changeover circuit 3 and a setting circuit 4 are constituted in such a way that they set a test mode in an erased state of a memory element M and that they set a normal mode in a written state. In a semiconductor integrated circuit device 10 the test mode is automatically set in an initial state that the memory element M is not written. Accordingly, it is possible to efficiently execute a test to detect a breakdown, to diagnose an operation or the like in this state. If this test is completed, only a product judged to be good is selected; a prescribed write voltage is impressed on power-supply terminals P1, P2; the memory element M is written; the test mode is released and the normal operation mode can be set. By this setup, a changeover between the normal mode and the test mode can be set without increasing the number of terminals; it is possible to detect the breakdown or to diagnose the operation easily.</p> |
