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FDCP_1

D Flip-Flop with Negative-Edge Clock and Asynchronous Preset and Clear

XC3000
XC4000E
XC4000X
XC5200
XC9000
Spartan
SpartanXL
Virtex
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Primitive

figures/x8357.gif

FDCP_1 is a single D-type flip-flop with data (D), asynchronous preset (PRE) and clear (CLR) inputs, and data output (Q). The asynchronous PRE, when High, sets the Q output High; CLR, when High, resets the output Low. Data on the D input is loaded into the flip-flop when PRE and CLR are Low on the High-to-Low clock (C) transition.

The flip-flop is asynchronously cleared, output Low, when power is applied. Virtex simulates 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_VIRTEX symbol.

Inputs
Outputs
CLR
PRE
D
C
Q
1
X
X
X
0
0
1
X
X
1
0
0
0

0
0
0
1

1

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