| 摘要 |
PURPOSE:To get rid of a defect such as oscillation does not stop by the intra-key- matrix wiring capacity coupling when turning on and off a key, in a key input device which stops a scanning oscillation when turning off a key, and starts the oscillation when turning on one key. CONSTITUTION:When one key of a keyboard matrix 3 is turned on, it is detected, an oscillating circuit 1 starts its oscillation, a scanning signal is formed through a timing generating circuit 2 and a scan outputting circuit 4, and this signal is encoded in an encoder circuit 6 through a key inputting circuit 5. When the key is turned off, the scanning signal is not inputted to said circuit 5, and a timer circuit 10 for inhibiting a key input and read is operated at the time of rise of a key input deciding and detecting signal from a deciding circuit 7. When this timer time is made longer enough than the time when the scanning signal is applied to the circuit 5 by the capacity coupling, the oscillation stops at the time of an output from the timer circuit 10. |
