| 摘要 |
PURPOSE: A circuit for inputting a key signal is provided to prevent lowering of the efficiency in sending signals and to simplify the progress of manufacturing and to reduce the prices by reducing input terminals of a micom and signal lines to the minimum unconcerned with the number of touch switches. CONSTITUTION: A circuit for inputting a key signal includes a signal managing portion, and a micom. The signal managing portion includes key sensing portions(521-52n), latches (531-53n), transistors(Q1-Qn/2) and resistance arrays(R1-Rn). The key sensing portions(521-52n) input the select signal output from the micom or the reverse select signal and sense the input of a key through each touch switch in the enable section of the select signal or the reverse select signal. The latches(531-53n) input the select signal or the reverse select signal and output the output of the key sensing portions(521-52n) by locking it with the select signal or the reverse select signal. The transistors(Q1-Qn/2) permit the output of the latch, in which the select signal is permitted, and the latch, in which the reverse select signal is permitted to the base in common. The resistance arrays(R1-Rn) are connected in series and the collectors of each transistor are connected between resistances and the output line between the resistances is connected to the micom.
|
