| 摘要 |
<p>PURPOSE:To protect existent data without erroneously writing data when a power source is inputted and canceled by providing a circuit to activate a storing element when the connecting signal of a memory card and an access signal to the memory card are simultaneously turned on. CONSTITUTION:When the power source is inputted and canceled in a condition that the memory card is connected to a read/write device, a latch 3 for control signal is cleared by a reset signal and all outputs to include the access signal to the memory card go to be a low level. However, since the output of an inverter 10 goes to be a high level and the output of an OR gate 11 also go to be the high level, a buffer 8 for control signal is in an inactive condition and the output of the buffer goes to be a high impedance. The level of the control signal, which is supplied to an EEPROM7 goes to be the high level by a pull-up resistance 9 and the EEPROM7 goes to be in a non-active condition. Thus, the existent data can be protected without erroneously writing the data.</p> |
