Define false path
Syntax
set_false_path [‑setup] [‑hold] [‑rise] [‑fall] [‑reset_path]
[‑from <args>] [‑rise_from <args>] [‑fall_from <args>] [‑to <args>]
[‑rise_to <args>] [‑fall_to <args>] [‑through <args>]
[‑rise_through <args>] [‑fall_through <args>] [‑quiet] [‑verbose]
Usage
Name | Description |
---|---|
[-setup]
|
Eliminate setup timing analysis for paths |
[-hold]
|
Eliminate hold timing analysis for paths |
[-rise]
|
Eliminate only rising delays for the defined paths |
[-fall]
|
Eliminate only falling delays for the defined paths |
[-reset_path]
|
Reset this path before setting false path |
[-from]
|
List of path startpoints or clocks |
[-rise_from]
|
Apply to paths rising from the list of startpoints or clocks |
[-fall_from]
|
Apply to paths falling from the list of startpoints or clocks |
[-to]
|
List of path endpoints or clocks |
[-rise_to]
|
Apply to paths with rise transition at the list of endpoints or clocks |
[-fall_to]
|
Apply to paths with fall transition at the list of endpoints or clocks |
[-through]
|
List of through pins, cells or nets |
[-rise_through]
|
Apply to paths rising through pins, cells or nets |
[-fall_through]
|
Apply to paths falling through pins, cells or nets |
[-quiet]
|
Ignore command errors |
[-verbose]
|
Suspend message limits during command execution |
Description
Sets false timing paths in the design that are ignored during timing analysis.
Arguments
-setup
- (Optional) Eliminate setup timing analysis for specified timing paths.
-hold
- (Optional) Eliminate hold timing analysis for specified timing paths.
-rise
- (Optional) Eliminate rising delays for the specified timing paths.
-fall
- (Optional) Eliminate falling delays for the specified timing paths.
-reset_path
- (Optional) Reset the timing path before setting false path. This clears all exception-based timing constraints from the defined timing path.
-from
<element_name> - (Optional) List of path origins or clocks. A valid startpoint is a clock object, the clock pin of sequential logic, or an input or bidirectional port.
-rise_from
<element_name> - (Optional) Apply to paths rising from the list of origins or clocks
-fall_from
<element_name> - (Optional) Apply to paths falling from the list of origins or clocks
-to
<element_name> - (Optional) List of path endpoints or clocks
-rise_to
<element_name> - (Optional) Apply to paths with rise transition at the list of endpoints or clocks
-fall_to
<element_name> - (Optional) Apply to paths with fall transition at the list of endpoints or clocks
-through
<element_name> - (Optional) List of through pins, cells or nets
-rise_through
<element_name> - (Optional) Apply to paths rising through pins, cells or nets
-fall_through
<element_name> - (Optional) Apply to paths falling through pins, cells or nets
-quiet
- (Optional) Execute the command quietly, returning no messages from the command. The command also returns TCL_OK regardless of any errors encountered during execution.
-verbose
- (Optional) Temporarily override any message limits and return all messages from this command.
set_msg_config
command.Examples
The following example eliminates the setup timing for paths from the bftClk:
set_false_path -setup -from bftClk
The following example excludes paths between the two clocks from timing analysis:
set_false_path -from [get_clocks GT0_RXUSRCLK2_OUT] \
-to [get_clocks DRPCLK_OUT]