| 摘要 |
PURPOSE:To obtain a device which can protect effectively against a runaway of software in either of initial processing and normal processing when they differ in processing time, by providing a timer means wherein two different kinds of time are set. CONSTITUTION:Two different kinds of time are set in a timer means, which generates a reset signal to a processor when each of them elapses. For example, a high level signal is inputted invariably to the input D of a D type flip-flop D-FF11, an access signal from the processor is inputted to the clock input C, and the reset signal for the processor is applied to the reset input R. Then, a Q output is supplied from the D-FF11 to a switch 13, which is controlled to select either of time limit constant circuits 14 and 15, which is connected to a monostable multivibrator 12. The monostable multivibrator 12 generates pulses for a time determined by the connected time-limit constant circuit 14 or 15, and the inverted output Q of the monostable multivibrator 12 is supplied to the processor as a reset signal RESET. |
