| 摘要 |
PURPOSE:To reset a faulty microcomputer to its normal state by stopping temporarily the supply of power after detecting a latch-up state of a peripheral circuit or the microcomputer caused by noises or a runaway of the microcomputer to restore the abnormal state of the microcomputer and extracting the data obtained before the microcomputer becomes abnormal out of a nonvolatile memory. CONSTITUTION:If the ports of a peripheral circuit 3 and a microcomputer 2 are latched up by the external noises, etc., the microcomputer 2 decides that an input port exceeds its limit and stops the output frequency to be inputted to a BPF circuit 5. In case of the microcomputer 2 being runaway, outputs to the band filter circuit 5 is stopped. Thus the circuit 5 detects an abnormal frequency and outputs a rigger signal to a timer circuit 7. The circuit 7 turns off a switch part 6 for a fixed period of time to stop the supply of power to the microcomputer 2, the circuit 3, a nonvolatile memory 4 and the circuit 5. Thus the circuit 3 and the microcomputer 2 are recovered from their latch-up states. |
