| 摘要 |
PURPOSE: An obstacle watching device receives hardware for communication device is provided to improve reliability of a watching device and to be able to use a low performance CPU. CONSTITUTION: An obstacle device receives hardware interrupt signal and judges whether the signal is lock signal or not. If lock signal is offered, a control unit(22) interprets CPU control signal from a CPU interface part(25) and generates watching control signal to an accumulator(26). the control unit(22) reads data in registers by hardware interrupt signal and accumulates the result in a state resister(27). If the received signal is not a lock signal, the control unit(22) makes latch signal to access hardware to a device interface part(21). The control unit(22) stores the data to a second buffer(24) using buffer control signal and generates watching control signal to the accumulator(26). The accumulator(26) reads a state of hardware device following the control signal generated the control unit(22) and increases non-zero register value. Comparing the increased register value and the value of critical value register(28), the accumulator(26) generates detection signal to the CPU interface part(25) if the increased value exceeds the critical value. the CPU interface part(25) generates CPU interrupt signal after receiving the detection signal.
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