| 摘要 |
<P>PROBLEM TO BE SOLVED: To reduce the costs of a key matrix having a plurality of keys. <P>SOLUTION: When a key is depressed, first currents are driven from a first common node through a key matrix to a second common node via a first current path. The first measurement of the resistance value of the first current path is performed. Then, second currents are driven from a second common node via the key matrix to the first common node through a second current path. The second measurement of the resistance value of the second current path is performed. The depressed key is identified by using the first and second measurement. Each key is made to correspond to the unique set of the first and second measurement values. In one example, a non-linear resistance circuit is arranged at the terminal of the line conductor and column conductor of the key matrix so that the line resistance of the first current path can be measured independently of the column resistance of the second current path. <P>COPYRIGHT: (C)2012,JPO&INPIT |
