| 摘要 |
PURPOSE:To detect efficiently a defect in a short time by a simple test procedure, and to switch automatically the redundancy of a memory device on the basis of its result, by containing a means for detecting whether a defect exists or not in a semiconductor memory device. CONSTITUTION:Flag registers 15a, 15b and 15c are reset, subsequently, a test data setting signal TD0 is set to ''H'' state, TD1 is set to ''L'' state, and TE0 is set to ''H'' state. As a result, ''0'' information is written in the lump in each memory cell in a memory device. Next, a test timing signal TE1 is set to ''H'' state, and whether the information is written and held exactly in the memory cell concerned is inspected. Also, the test data setting signal TD0, TD1 and TE0 are set to ''L'', ''H'' and ''H'' states, respectively, ''1'' is written in the lump in each memory cell, and the memory cell is inspected. On the basis of the inspection result by said procedure, switching is executed automatically by a redundancy switching circuit 24. |
