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Table Of Contents
Modern Computer Architecture and Organization - Third Edition
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A device that changes its output state only when a clock signal transitions (from low to high or from high to low) is called an edge-sensitive device. Flip-flops are similar to latches, with the key difference that a flip-flop changes its output in response to a clock edge rather than continuously responding to its input while enabled.
The positive-edge-triggered D flip-flop is used in a wide range of applications. D flip-flops typically include set and reset input signals that perform the same functions as in the SR latch. This device has a D input that functions similarly to the D input of the gated D latch. Instead of an enable input, the D flip-flop has a clock input that triggers the transfer of the D input to the Q output and, with inversion, to the Q̄ output on the clock's rising edge. Outside a very narrow time window around the rising edge of the clock signal, the flip-flop does not respond to the value of the D input. When high, the S and R inputs override...