| 摘要 |
PURPOSE:To reset quickly the runaway state of a microprocessor to a normal state by resetting a microprocessor in case the signal of a specific pattern is not outputted onto a data bus for a fixed period of time or longer. CONSTITUTION:A pattern detecting circuit 2 outputs a reset signal for a counter circuit 3 by a signal line S2 as long as the input signal is equal to a specific pattern. No reset signal is outputted from the circuit 2 in case a specific pattern is not outputted in a fixed cycle onto a data bus B1 or no write control signal is supplied from a signal line S1 for a fixed period of time or longer. Therefore the circuit 3 transmits a pulse. A pulse generating circuit 4 outputs pulses when a pulse is supplied from the circuit 3 and resets a microprocessor 1. The data on a specific pattern is put into an optional address on a program.
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