Altera Quartus II Scripting - Manual (Page 615)

Chapter 3: Tcl Packages & Commands 3–485
timing_assignment
© July 2013 Altera Corporation Quartus II Scripting Reference Manual
create_base_clock
Usage
create_base_clock [-comment ] [-disable] [-duty_cycle ] [-entity
] -fmax [-no_target] [-tag ] [-target ] [-virtual]
Options
-comment : Comment
-disable: Option to disable assignment
-duty_cycle : Duty cycle
-entity : Entity to which to add clock assignment
-fmax : Clock frequency
-no_target: Option to not assign clock to node
-tag : Option to tag data to this assignment
-target : Clock node name
-virtual: Option to specify the clock as a virtual clock
: Clock name
Description
Creates the base clock. The base clock is an absolute clock.
The "-fmax" option can take the format:
For example, if the fmax is 10.55ns, "10.55" is the and "ns" is the .
The following table displays possible time units:
If you specify the "-virtual" option, the base clock is not assigned to any node in the timing netlist. You
cannot specify the "-virtual" option and the "-target" option at the same time.
For entity-specific assignments, use the "-entity" option to force the assignment to specified entity. If you
do not specify the "-entity" option, the value for the FOCUS_ENTITY_NAME assignment is used. If the
FOCUS_ENTITY_NAME value is not found, the revision name is used.
Time Unit Description
s second(s)
ms millisecond(s)
us microsecond(s)
ns nanosecond(s)
ps picosecond(s)
fs femtosecond(s)
Hz hertz
KHz kilohertz
MHz megahertz
GHz gigahertz