| 摘要 |
PURPOSE: To realize a memory module in which electrical an assembly check of a memory device and a test for write-in and read-out operations of simple data can be performed with an inexpensive tester, the number of input/output pins for test is small and data input/output characteristics of a memory device is not deteriorated. CONSTITUTION: Switch groups SD0a-SD7a are provided to data lines DQ0-DQ63 connected to memory devices MD0-MD7. The switch groups SD0a-SD7a connect whole data lines DQ0-DQ63 to the outside of a memory module MMa at the time of a memory operation, and connect them to the input terminal of an exclusive NOR circuit EXa after common one bit data are written into each memory devices MD0-MD7 at the time of a test operation. The erroneous operation of the memory devices MD0-MD7 is detected by an output signal TMSa of the exclusive NOR circuit EXa.
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