User guide

14-6
Negative Timing Checks
Figure 14-4 ASIC Cell with Long Propagation Delays on Data Events
The violation window shifts to the left when there are longer
propagation delays on the data event. This left shift requires a
negative hold limit:
$setuphold (posedge clock, data, 31, -10, notifyreg);
Figure 14-5 illustrates this scenario.
Figure 14-5 Negative Hold Limit
causes
long
delay
causes short delay
clock
data
clk
d
q
setup
limit
hold
limit
violation window
reference
event
data
event
data
event
clock
data
0
31
10