| 摘要 |
A glitch protect valid cell and method for maintaining a desired logic state value in response to a glitch signal and a timing signal. The glitch protect valid cell may be integrated with a content addressable memory (CAM) array for indicating whether word data stored within the CAM is valid. The glitch protect valid cell includes a memory element, a state machine, and a glitch protect circuit each responsive to one another. The glitch protect circuit includes a propagation delay assembly and a restore assembly electrically coupled to one another. The propagation delay assembly includes a first pull down network and a NOR gate electrically coupled to one another. The restore assembly includes a second pull down network electrically coupled to the propagation delay assembly. The first pull down network is responsive to the glitch signal and the timing signal to selectively engage the NOR gate. In a glitch protect condition, the glitch protect valid cell restores the initial logic state value of the true valid bit despite at least one glitch signal invalidating the initial value. As such, the first pull down network resets the initial state value of the true valid bit according to the timing signal and the glitch signal supplied to the glitch protect circuit. The initial state value of a true valid bit is restored in the memory element with the second pull down network via the timing signal and a restore signal provided by an enabled pull up network within the NOR gate. Specifically, the second pull down network is responsive to the pull up network selectively enabled within the NOR gate and resets the complement valid bit in the memory element to consequently restore the initial state value of the true valid bit.
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