| 摘要 |
PROBLEM TO BE SOLVED: To expand the storage capacity which a system can use without being accompanied with the increase in the number of chip enable signals required for control and the drop in access speed by switching a flash memory chip where the value of bit data in higher order than a bit positioned in the highest order coincides with the value of an allocated extension address into an accessible state. SOLUTION: A chip select circuit 130 of the flash memory 100 deals with the value of bit data of an inputted address signal as an extension address and selects a chip to which the extension address is allocated as an access object. A decoder 121 outputs control signals to NAND gates 122-125 by the value of the bit data of an address signal inputted through bins 112 and 113. The NAND gates 122-125 output signals corresponding to the control signals to a chip enable terminal and switch the chips 117-120 to which the extension addresses and address spaces are allocated into an accessible state.
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