| 摘要 |
PURPOSE:To shorten the key operating time by forming a key matrix with 3-contact key switches in addition to the 1st and 2nd contacts connected to the 1st and 2nd ports and a 3rd contact of a prescribed potential and controlling simultaneously these 1st-3rd contacts in a conductive or nonconductive state. CONSTITUTION:When an optional key switch S21, for example, is pushed, the voltage VCC is supplied to a terminal A1 of an input port A as well as to a terminal B4 of an input port B. Thus both blocks A and B are actuated and therefore a specific key switch that is pushed in a block C is decided based on the input data on both ports A and B. Then the push of the switch S21 is decided. In the same way, another pushed switch is also decided in case an input operation is carried out with push of said switch. Thus it is possible to easily perform a quick input operation in a simple constitution.
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