| 摘要 |
PURPOSE:To simplify the constitution by using an ROM to output a switch operating signal and generate a strobe in a chattering prevention circuit of plural switch groups and using a delay circuit in common to each group so as to eliminate chattering. CONSTITUTION:A switch number signal (A0-A2) corresponding to a depressed switch in witch groups G1-G3 is fed to the ROM 8 as an address and a signal representing which switch of which group is depressed is fed to a D-FF9 accord ingly. The ROM 8 gives a strobe to a delay circuit 10 at the same time and the D-FF stores the output of the ROM 8 by using the delay output after the chattering period at switch-on. The output of the delay circuit 10 is fed to the ROM 8 via a delay circuit 11 to cancel the output data of the ROM 8 after the chattering period at switch-off. No strobe generating circuit for each input device is required and the constitution is simplifed. |
