| 摘要 |
PURPOSE:To eliminate a diode for preventing non-operation signal and to miniaturize a key input device, by inhibiting the processing of an operation signal when a counting value is discriminated as >=2 after counting the operation signals supplied from an output line. CONSTITUTION:The timing signals which are time-divided to input lines a0- a3 are supplied to key switches S00-S33 which are distributed in a matrix form form an input controlling part 6 via a buffer 8. The timing signal is delivered to output lines b0-b3 with operation of one of the switches S00-S33 and then supplied to counters 3a-3d as well as to the part 6 via a buffer 7. The counters 3a-3d count the timing signals, and a detecting signal is supplied to the part 6 from a line C2 via an OR gate 4 when the counting value of the timing signals becomes >=2. The part 6 transmits a resetting signal to a line C1 when the detecting signal is decided as a non-operation signal and at the same time delivers an inhibition code to the lines a0-a3 from an inhibition memory M to inhibit the processing of the operation signal. |
