FDRS_1

D Flip-Flop with Negative-Clock Edge and Synchronous Reset and Set

FDRS_1 is a single D-type flip-flop with data (D), synchronous set (S), and synchronous reset (R) inputs and data output (Q). The synchronous reset (R) input, when High, overrides all other inputs and resets the Q output Low during the High-to-Low clock (C) transition. (Reset has precedence over Set.) When S is High and R is Low, the flip-flop is set, output High, during the High-to-Low clock transition. When R and S are Low, data on the (D) input is loaded into the flip-flop during the High-to-Low clock transition.

The flip-flop is asynchronously cleared, output Low, when power is applied. Virtex and Spartan2 simulate power-on when global set/reset (GSR) is active. GSR defaults to active-High but can be inverted by adding an inverter in front of the GSR input of the STARTUP_SPARTAN2 or STARTUP_VIRTEX symbol.

Inputs				Outputs
R	S	D	C	Q
1	X	X		0
0	1	X		1
0	0	1		1
0	0	0		0