| 摘要 |
PURPOSE:To prevent increase of memory space that can not be accessed by increase of the number of banks by inputting a data signal and selecting a memory space at the time of a bank switching mode. CONSTITUTION:When an address signal for bank switching is inputted, the mode goes to a bank switching mode. Supposing that a data signal corresponding to bank Bm is inputted from an inputting buffer 16, the FF 32 is set, and a bank enable signal BEm is retained at high level, and the bank Bm goes to the state of selection. When the set signal Sm of FF 32 goes to high level, resetting is made to FF32 of all other banks B1-Bm-1. Bank enable signals BE1-BEm-1 are retained at low level, and other banks are not selected. When a bank other than the bank Bm is selected, one of input signals S1-Sm-1 of an OR circuit 30 of the bank Bm goes to high level, and accordingly, FF32 of the bank Bm is reset, and the bank Bm is switched to the state of non- selective.
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