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