| 摘要 |
PURPOSE:To reduce the consumption of electric power and also reduce a chip area of an integrated circuit by discriminating and processing keys only for a prescribed period after the variation of a significant input through a selective differential circuit, an FF, a clock generating circuit and a key input deciding circuit, etc. CONSTITUTION:A selective differential circuit 10 detects signals from key input group SW1-SW3 and its output sets up an FF20, permitting an output signal (a) of the FF20 and the output of a sampling clock generating circuit 30. Subsequently an output signal (b) of the circuit 30 and a key input discriminating circuit 40 are actuated and, after prescribed discrimination, a signal (c) for resetting the FF20 is outputted and a key input is detected only for a prescribed period after the variation of a significant input from a circuit 10. When every key input signal coincides over the prescribed number of sampling times, it is discriminated that the circuit 40 has no chattering. |
