LDE

Transparent Data Latch with Gate Enable

LDE is a transparent data latch with data (D) and gate enable (GE) inputs. Output Q reflects the data (D) while the gate (G) input and gate enable (GE) are High. The data on the D input during the High-to-Low gate transition is stored in the latch. The data on the Q output remains unchanged as long as G or GE remain 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	1	0	0
1	1	1	1
1	0	X	No Chg
1		D	d
d = state of input one setup time prior to High-to-Low gate transition