| 摘要 |
PURPOSE:To eliminate the need for formation in an input/output cell region of an input/output circuit exclusive for a test, and to use the input/output cell region efficiently by sharing an input/output circuit and changing over a memory circuit to a normal operation mode or a test mode. CONSTITUTION:A detecting signal is output when a signal detector detects a command signal commanding the test of a memory circuit 30, and a changeover circuit 33 changes over connection to the memory circuit 30 through a logic circuit 34 of an input/output circuit 31 or direct connection to the memory circuit 30 of the input/output circuit 31 in response to the detecting signal output from the signal detector. Consequently, the memory circuit 30 can be changed over to a normal operation mode or a test mode, sharing the input/output circuit 31. Accordingly, an input/output circuit 31 exclusive for a test need not be shaped in an input/output cell region, and other input/output cell regions can be used for the input/output of circuits except the memory circuit 30 while the memory circuit 30 can be tested. |
