| XC3000 | XC4000E | XC4000X | XC5200 | XC9000 | Spartan | SpartanXL | Virtex |
|---|---|---|---|---|---|---|---|
| N/A | N/A | N/A | N/A | N/A | N/A | N/A | Primitive |
FDE is a single D-type flip-flop with data input (D), clock enable (CE), and data output (Q). When clock enable is High, the data on the D input is loaded into the flip-flop during the Low-to-High 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 | ||
|---|---|---|---|
| CE | D | C | Q |
| 0 | X | X | No Chg |
| 1 | 0 |  | 0 |
| 1 | 1 | | 1 |
