| 摘要 |
PURPOSE:To surely detect interruption whether it is caused by a noise, etc., or produced by a proper interrupt signal, by discriminating the state of an interruption requesting FF at the beginning of the interruption processing. CONSTITUTION:When a signal inpressed upon an interruption input terminal INT becomes '0' due to a noise, '1' is again impressed upon the terminal INT during a waiting time T, since the time T is set in a microcomputer 1 by means of a timer. Therefore, both an output terminal A1 and the input terminal INT become '0' and the fall is detected by a detecting circuit 2. After the fall is detected, an interruption requesting FF 3 is set. Therefore, an interruption requesting signal INTREQ is discriminated as '1' and the signal impressed upon the input terminal INT is discriminated as a noise, and the successive interruption processing program is not executed, but a prescribed instruction is executed and the FF 3 is reset. Furthermore, an interruption permitting FF 9 is set by means of a set instruction and operations are returned to the original program. |
