Intel® Quartus® Prime Pro Edition User Guide: Scripting

ID 683432
Date 12/13/2021
Public

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3.1.27.7. derive_clocks (::quartus::sdc)

The following table displays information for the derive_clocks Tcl command:

Tcl Package and Version

Belongs to ::quartus::sdc

Syntax derive_clocks [-h | -help] [-long_help] -period <period_value> [-waveform <edge_list> ]
Arguments -h | -help Short help
-long_help Long help with examples and possible return values
-period <period_value> Speed of the default clock in terms of clock period
-waveform <edge_list> List of edge values
Description
Creates a clock on sources of clock pins in the design that do not
already have at least one clock sourcing the clock pin. This command
is equivalent to calling create_clock on each clock source in the
design that does not already have a clock assigned to it.

See the help for create_clock for more information.

Intel does not recommend using this command during final sign-off
analysis of a design. derive_clocks should only be used early in the
design phase when the clocks are not completely known. When possible,
create_clock and create_generated_clock should be used instead.
Example Usage
# Automatically create a 10ns, 60% duty cycle clock on all
# unconstrained clock sources
derive_clocks -period 10 -waveform {0 6}
Return Value Code Name Code String Return
TCL_OK 0 INFO: Operation successful

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