- The list of nodes for the
-through
option should be a list of valid pins, ports, or nets. - Multiple elements can be provided.
By default, the timing engine includes the clock skew inside the slack computation.
The -datapath_only
option can be used to remove the clock skew from
the slack computation. The -datapath_only
option is supported only
by the set_max_delay
command, and requires the
-from
option.
The following table summarizes the impact of -datapath_only
in the
behavior of set_max_delay
constraint.
The common behavior for the path delay calculation of set_max_delay
with or without -datapath_only
is:
- Input delay is included in the path delay calculation when the path starts on an
input port and that a
set_input_delay
has been specified on the port - Output delay is included in the path delay calculation when the path ends on an
output port and that a
set_output_delay
has been specified on the port - The data pin setup time is included in the path delay calculation when the path ends on the data pin of a sequential element.
set_max_delay | set_max_delay -datapath_only | |
---|---|---|
Path delay calculation | Skew included when the constraint starts on the clock pin of a sequential element or ends on the data pin of a sequential element. | Skew never included. |
Hold Requirement | Untouched | False-ed path |
-from Option | Optional | Mandatory |