Libraries GuideChapter 7: Design Elements (LD to NOR16)
LDE_1
Transparent Data Latch with Gate Enable and Inverted Gate
XC3000
| XC4000E
| XC4000X
| XC5200
| XC9000
| Spartan
| SpartanXL
| Spartan2
| Virtex
|
|---|
N/A
| N/A
| N/A
| N/A
| N/A
| N/A
| N/A
| Primitive
| Primitive
|
LDE_1 is a transparent data latch with data (D) and gate enable (GE) inputs. Output Q reflects the data (D) while the gate (G) input is Low and gate enable (GE) is High. The data on the D input during the Low-to-High gate transition is stored in the latch. The data on the Q output remains unchanged as long as G is High or GE is Low.
The latch 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
|
|---|
GE
| G
| D
| Q
|
|---|
0
| X
| X
| No Chg
|
1
| 0
| 0
| 0
|
1
| 0
| 1
| 1
|
1
| 1
| X
| No Chg
|
1
| 
| D
| d
|
d = state of input one setup time prior to Low-to-High gate transition
|
