2.3.1 Gated D Flip-Flop

The D flip-flop (DFF) is a widely used and is often called "data" or "delay" flip-flop. When G input is high, the flip-flop captures the value of the D-input and the captured value becomes the Q output. If the G input is low, the D input is ignored and the Q output is unchanged from its last state. The DFF can be seen as a memory cell, a zero-order hold, or a delay line.

The D-input is driven by the even LUT output (LUT0), and the G-input is driven by the odd LUT output (LUT1).