| 摘要 |
<p>PROBLEM TO BE SOLVED: To eliminate the need for developing a larger unrewritable nonvolatile memory than existing one by providing an interface circuit corresponding to external access that handles a specific number of unrewritable nonvolatile memories as a single rewritable nonvolatile memory having the same address. SOLUTION: The interface circuit 4 is provided corresponding to flash memories 2 and 3 and the interface circuit 4 tests the flash memory 3 as a single 16×1M-bit flash memory having 16-bit output data width in the case of mode select signals S=1 and S=0. Further, when the mode select signals are set to S1=1 and S2=1 and address signals are set to A19=1 and A18=1, the flash memory 2 is selected and when the address signals are set to A19=1 and A18=0, the flash memory 3 is selected. Therefore, the development cost can be reduced and the development time can be shortened.</p> |
