Intel® Quartus® Prime Pro Edition User Guide: Scripting

ID 683432
Date 12/13/2021
Public

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Document Table of Contents

3.1.28.6. get_fanins (::quartus::sdc_ext)

The following table displays information for the get_fanins Tcl command:

Tcl Package and Version

Belongs to ::quartus::sdc_ext

Syntax get_fanins [-h | -help] [-long_help] [-asynch] [-clock] [-inverting_paths] [-no_logic] [-non_inverting_paths] [-stop_at_clocks] [-synch] [-through <names> ] <filter>
Arguments -h | -help Short help
-long_help Long help with examples and possible return values
-asynch Traverse through asynch edges
-clock Traverse through clock edges
-inverting_paths Only follow inverting combinational paths
-no_logic Do not follow combinational paths
-non_inverting_paths Only follow non-inverting combinational paths
-stop_at_clocks Return clock targets as fanin/fanouts rather than traversing through them
-synch Traverse through synch edges
-through <names> Valid through nodes (string patterns are matched using Tcl string matching)
<filter> Valid starting nodes (string patterns are matched using Tcl string matching or collection)
Description

Returns a collection of fanin ports, registers (and optionally clock targets) reachable from the <filter> in the design. When you supply the -no_logic option, get_fanins ignores paths that pass through combinational logic elements other than buffers and inverters. NOTE: the -no_logic option does not consider logic absorbed into the cells of the <filter> nor the cells of fanin registers, ports or clock targets. When you use -synch, -asynch, or -clock options, get_fanins traverses the netlist through corresponding edges. You can specify more than one of these options. If you do not specify any of these three options, the command does not ignore any paths. When the -non_inverting_paths option is used, no_logic does not follow any paths that includes odd number of inverters. Similarly, when the -inverting_paths option is used, no_logic does not follow any paths that includes 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 fanins that can be reached by going through those nodes are returned. When -stop_at_clocks is used, combinational clock targets may be returned (in addition to clock or non-clock registers and ports), and registers or ports that can only be reached by traversing through a clock target will not be returned. The filter for the collection is a Tcl list of wildcards, and must follow standard Tcl or Timing Analyzer-extension substitution rules. See the help for the use_timing_analyzer_style_escaping command for details.

Example Usage
set fanins [get_fanins $item -synch -clock]
foreach_in_collection fanin_keeper $fanins {
	lappend fanin_keeper_list [get_node_info $fanin_keeper -name]
}

set fanins_no_logic [get_fanins $item -no_logic -asynch]
foreach_in_collection fanin_keeper $fanins_no_logic {
	lappend fanin_keeper_list_no_logic [get_node_info $fanin_keeper -name]
}

#-through example
get_fanins inst18 -through inst11
Return Value Code Name Code String Return
TCL_OK 0 INFO: Operation successful

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