| 摘要 |
PURPOSE:To easily and securely store data by using a random access memory RAM to external data input and output, storing the data of the RAM on a read-only memory EEPROM which is electrically erasable, and using a microprocessor for control between those memories. CONSTITUTION:The memory card is connected to external equipment 1 and when the memory card is powered on by an external power source 11, a power source monitor part 7 outputs a power source normalcy signal 12. Then, the microprocessor 5 starts operating to transfer the contents of the EEPROM 4 to the RAM 3 through an internal address bus 14 and an internal data bus 15. When the transfer is completed, the microprocessor 5 outputs a card readable signal as a memory card control signal 10. The external equipment recognizes that the memory card is usable from the card OK signal and inputs and outputs data to and from the RAM 3 through an external address bus 8 and an external data bus 9. Consequently, target data can securely be held on the memory card. |
