User guide

13-35
SDF Backannotation
Simultaneous Multiple Source Transitions
When there are simultaneous transitions on more than one source
port instance, the algorithm for the +multisource_int_delays
option applies the shortest delay to all of these transitions instead of
the one specified in the SDF file.
For example, if the SDF file specifies the following:
(CELL
(CELLTYPE "stim")
(INSTANCE stim)
(DELAY
(ABSOLUTE
(INTERCONNECT stim.left1.bot1.botout stim.right1.rightin (2))
(INTERCONNECT stim.left1.lout1 stim.right1.rightin(1))
)
)
)
Here the delay values are reversed from the previous SDF example.
The delay from output port botout to rightin is 2 and the delay
from output port lout1 to rightin is 1.
Figure 13-2 shows the waveforms for these ports and for net int that
connects these ports and to which you backannotate the
INTERCONNECT delay.
Figure 13-2 Simultaneous Source Transitions