| 摘要 |
PURPOSE:To reduce the number of signal lines, and to miniaturize a connector, by dividing a key into groups. CONSTITUTION:Key switches 1-4 are connected to a common line CMN0 through diodes 19-22 as a first group, and key switches 5-8 are connected to a common line CMN1 through a diode group as a second group, and key switches 9-12 are connected to a common line CMN2 through the diode group as a third group. In such constitution, the detection of key operations for the keys 1-4 (the first group) are performed at a period T1 in the first cycle of dynamic scan, and a light emitting diode 13 is lightened. At the next period T2, the detection of the key operations for the keys 5-8 (the second group) are performed. At the next period T3, the detection of the key operations for the keys 9-12 (the third group) are performed, and simultaneously, a light emitting diode 15 is lightened. |
