| 摘要 |
PURPOSE: An apparatus for detecting a clock error without an external clock source and an operation method thereof are provided, which can detect an error of a clock under the condition that an external oscillator can not be attached in a space in a board. CONSTITUTION: The first divider part(11A) divides a duplicated signal into two, and the second divider part(12A) divides the signal divided in the first divider part into two. An XOR gate(15A) performs an XOR operation by reading the signal divided in the second divider part and a signal divided in the first divider part(11B) of a block processing another side of the duplicated signal through two D-flip flops(13A,14A). A latch-inverter part(16A) latches an output of the XOR gate with the signal divided in the first divider part(B) and inverts it. And a count-comparison part(17A,18A) indicates whether an input signal has an error or not, by comparing a counting value of an inverted signal of the output signal of the latch-inverter part with an non-inverted signal of the output signal of the latch-inverter part.
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