| 摘要 |
PURPOSE:To form a nonvolatile external memory of easy access, high speed and large capacity, by combining a nonvolatile memory and a random access semiconductor memory. CONSTITUTION:Accessing is done to the random access semiconductor memory 11 only when an access request signal 6 is outputted, data of write data transfer 16 are written in an address represented with an address 20 when a write command 17 is given, the data of the address when read commands 191-193 are given is read out for read data transfer 181-183. In an example shown in Figure, since a new data is written in an address 0 with the write command 17, this data should be written in a corresponding address to a disc memory 1. This write is done in the intervals of the data transfer of the random access semiconductor memory 11. The write to the disc memory 1 should be completed before the power supply is interrupted 43. The control mentioned above is done by a controller 13 using a microcomputer, for example. |
