| 摘要 |
PURPOSE:To use effectively an EPROM by limiting the access to the EPROM to one of plurally divided parts of memory capacity, and allocating selectively one divided area to one of plurally divided parts of the memory on an address. CONSTITUTION:Address signals a0-a12 from a control circuit 1 and the output of an OR gate 7 are given to an address decoder 3, and one address on an EPROM2 is selected by the address decoder 3. If the address exceeds 4k when 4k-number of bytes are selected, a NAND gate 13 reports it to the control circuit 1 that the address exceeds 4k, and the output of the EPROM2 is stopped.
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