| 摘要 |
PURPOSE:To avoid the erroneous writing of a memory circuit as well as the breakdown of an internal semiconductor by turning on a power supply circuit and then a three-state buffer when a memory circuit is inserted and turning off the three-state buffer and then the power supply circuit when the memory circuit is pulled out respectively. CONSTITUTION:When a memory card 1 is connected to a terminal of an interface 24 set at the equipment side, two terminals of a short pin terminal 21 are connected to each other and a put-in/put-out signal 10 is set at an earth potential for the first time. Thus, the output side of a buffer 14 is set at 'L' and a power supply circuit 20 works. Then, the power supply input of the circuit 20 serves as the power supply for the card 1 via a transistor Trs. The power supplied to the card 1 is applied to an input terminal of an OR circuit 16 via an inverting circuit 15 as a power supply ON signal 12. At the same time, the signal 10 is sent to the other input terminal of the circuit 16 and the output 13 of the circuit 16 is set at 'L' to turn on a unidirectional buffer 17 and a bidirectional buffer 7. When the card 1 is pulled out, a three-state buffer and then the circuit 20 are turned off.
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