| 摘要 |
An apparatus comprising a clock for providing a clock signal, means for providing a delayed version of the clock signal, two transparent latches having clock inputs controlled by opposite polarities of the delayed clock signal, a multiplexer having (i) inputs fed by outputs of the latches, and (ii) a select input fed by the clock signal, and means for providing a select signal for selecting the latch whose clock is inactive. Preferably, each of the latches has a scan input gate and a scan output gate, and the scan output of the first latch is applied to the scan input of the second latch to form a scannable latch pair. Also, preferably, the apparatus further comprises a data port for applying data to the first and second latches, and an exclusive OR gate at the data port, whereby the apparatus produces a gated clock signal. Also disclosed is a method of operating this apparatus.
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