| 摘要 |
<p>PURPOSE:To realize a long service life of the IC memory card by constituting the card so that a power is supplied to only a RAM chip in which data is stored, and the power source is not supplied to a RAM in which data is not written. CONSTITUTION:At the time of write and at the time of read-out of data, a software of an external device 2 discriminates a use state of a file, and writes switch data in a register 40 so that a power is supplied to only an effective RAM chip in RAMs 11 - 14. A switch signal is supplied to only a switch circuit being the corresponding bit '1' of the switch data held in this register, and the power source is supplied to the connected RAM. In such a way, in an IC memory card 1 of a large capacity constituted of plural RAM-ICs, the storage contents can be saved for a long period by realizing a long service life of a built-in battery 30.</p> |
