multicycle path (set_cycle_addition)
Paths are described using from/through/to parameters and the specified
cycle_value is added to the paths. This can be used to describe
multicycle paths, 1/2 cycle paths, etc.
type contraint
applies to paths
depends on
verified by timing analysis
parameters
name value type semantics
from list of pins (see to parameter semantics)
through list of pins (see to parameter semantics)
to list of pins from/through/to used to describe paths
that span multiple cycles. Note there
can be multiple throughs. Each parameter
can be a list. A path matches the pattern
if at least one pin in the parameter list
is on the path, and each parameter is
satisfied. The order of the throughs
is also important.
from_clock clock_name (See multicycle path to_clock parameter)
to_clock clock_name This is similar to the from/to paramter,
except that all registers triggered by
the specified clock are considered as the
from/to of the path.
from_edge rise/fall The edge on the from pin(s).
through_edge rise/fall The edge on the through pin(s).
to_edge rise/fall The edge on the to pin(s).
analysis_type early/late The early paths can be described separately
from the late paths.
cycle_value float The number of cycles that are added
to the paths described by the from/through/to
parameters. Note, all paths by default have
one cycle. The cycle_value for a two
cycle paths would be 1.
Negative numbers and fractions can also be
used to get 1/2 cycle paths.
disable path (set_false_path)
Paths are described using from/through/to parameters and these paths
are disabled.
type contraint
applies to paths
depends on
verified by timing analysis
parameters
name value type semantics
from list of pins
through list of pins
to list of pins (See multicycle path to parameter)
from_clock clock_name
to_clock clock_name (See multicycle path to_clock parameter)
from_edge rise/fall The edge on the from pin(s).
through_edge rise/fall The edge on the through pin(s).
to_edge rise/fall The edge on the to pin(s).
analysis_type early/late The early paths can be described separately
from the late paths.
disable arc in library cell (affects all instances) (set_disable_cell_timing)
This command disables a timing on a library cell, disabling the timing
arc on all instances of that cell. The arc is specified with a from_pin
and a to_pin.
type contraint
applies to library cell
depends on
verified by timing analysis
parameters
name value type semantics
library_name library_name The library where the cell is found.
cell_name cell_name The cell on which the arc is to be disabled.
from_pin pin_name The from pin on the arc.
to_pin pin_name The to pin on the arc.