Altera SDC and TimeQuest API - Manual (Page 58)

2–48 Chapter 2: SDC and TimeQuest API Package and Commands
sdc_ext
SDC and TimeQuest API Reference Manual © December 2009 Altera Corporation
get_fanouts
Usage
get_fanouts [-inverting_paths] [-no_logic] [-non_inverting_paths] [-through ]
Options
-inverting_paths: Only follow inverting combinational paths
-no_logic: Do not follow combinational paths
-non_inverting_paths: Only follow non-inverting combinational paths
-through : Valid through nodes (string patterns are matched using Tcl string
matching)
: Valid starting nodes (string patterns are matched using Tcl string matching
or collection)
Description
Returns a collection of fanout nodes starting from the in the design. When the -no_logic option is
used, get_fanouts ignores the paths that pass through combinational logic elements other than buffers and
inverters.
When the -non_inverting_paths option is used in conjunction with the -no_logic option, get_fanouts does
not follow any paths that include an odd number of inverters. Similarly, when the -inverting_paths option
is used in conjunction with the -no_logic option, get_fanouts does not follow any paths that include an
even number of inverters. Both the -non_inverting_paths and -inverting_paths options require the
-no_logic option and are mutually exclusive.
When the -through option is used, only the fanouts that can be reached by going through those nodes are
returned.
The filter for the collection is a Tcl list of wildcards, and must follow standard Tcl or TimeQuest-extension
substitution rules. See the help for use_timequest_style_escaping for details.
Example
set fanouts [get_fanouts $item]
foreach_in_collection fanout_keeper $fanouts {
lappend fanout_keeper_list [get_node_info $fanout_keeper -name]
}
set fanouts_no_logic [get_fanouts $item -no_logic]
foreach_in_collection fanout_keeper $fanouts_no_logic {
lappend fanout_keeper_list_no_logic \
[get_node_info $fanout_keeper -name]
}
# Using through option to find the fanout registers whose enable input is
# connected to the signal while ignoring the inverting paths.
get_fanouts inst1 -no_logic -non_inverting_paths -through \
[get_pins -hierarchical *|ena]