Tcl Package and Version |
Belongs to ::quartus::sta 1.0
|
Syntax |
report_skew [-h | -help] [-long_help] [-append] [-detail <summary|path_only|path_and_clock|full_path>] [-exclude <Tcl list>] [-fall_from_clock <names>] [-fall_to_clock <names>] [-file <name>] [-from <names>] [-from_clock <names>] [-greater_than_skew <slack limit>] [-include <Tcl list>] [-multi_corner] [-npaths <number>] [-panel_name <name>] [-rise_from_clock <names>] [-rise_to_clock <names>] [-show_routing] [-stdout] [-through <names>] [-to <names>] [-to_clock <names>] |
Arguments |
-h | -help |
Short help |
|
-long_help |
Long help with examples and possible return values |
-append |
If output is sent to a file, this option appends the result to that file. Otherwise, the file will be overwritten. This option is not supported for HTML files. |
-detail <summary|path_only|path_and_clock|full_path> |
Option to determine how much detail should be shown in the path report |
-exclude <Tcl list> |
A Tcl list of parameters to exclude during skew analysis. This list can include 1 or more of the following: utsu, uth, utco, from_clock, to_clock, clock_uncertainty, ccpp, input_delay, output_delay, odv |
-fall_from_clock <names> |
Valid source clocks (string patterns are matched using Tcl string matching) |
-fall_to_clock <names> |
Valid destination clocks (string patterns are matched using Tcl string matching) |
-file <name> |
Sends the results to an ASCII or HTML file. Depending on the extension |
-from <names> |
Valid sources (string patterns are matched using Tcl string matching) |
-from_clock <names> |
Valid source clocks (string patterns are matched using Tcl string matching) |
-greater_than_skew <slack limit> |
Limit the paths reported to those with skew values greater than the specified limit. |
-include <Tcl list> |
Tcl list of parameters to include during skew analysis. This list can include 1 or more of the following: utsu, uth, utco, from_clock, to_clock, clock_uncertainty, ccpp, input_delay, output_delay, odv |
-multi_corner |
When set, running this command with the -panel option will create a folder containing versions of this report for multiple operating conditions. This option has no effect when used with the -stdout or -file options. |
-npaths <number> |
Specifies the number of paths to report for each latest and earliest arrival skew result (default=1) |
-panel_name <name> |
Sends the results to the panel and specifies the name of the new panel |
-rise_from_clock <names> |
Valid source clocks (string patterns are matched using Tcl string matching) |
-rise_to_clock <names> |
Valid destination clocks (string patterns are matched using Tcl string matching) |
-show_routing |
Option to display detailed routing in the path report |
-stdout |
Send output to stdout, via messages. You only need to use this option if you have selected another output format, such as a file, and would also like to receive messages. |
-through <names> |
Valid through nodes (string patterns are matched using Tcl string matching) |
-to <names> |
Valid destinations (string patterns are matched using Tcl string matching) |
-to_clock <names> |
Valid destination clocks (string patterns are matched using Tcl string matching) |
Description |
This report performs skew analysis on selected
paths. As opposed to report generated by
report_max_skew command, this command does not depend
on the existance of set_max_skew assignments. This
report computes skew with respect to the latest and
the earliest arrival of each selected path.
By default, "Skew for the Latest Arrival" is computed
by comparing the latest arrival of each path with the
earliest arrival of the path that has the smallest
value for early arrival of all other paths included
in the constraint. Similarly, "Skew for the Earliest
Arrival" is computed by comparing the earliest arrival
of each path with the latest arrival of the path that
has the largest value for late arrival of all other
paths included in the constraint. No path is compared
with itself.
When on-die variation is excluded, "Skew for the Latest
Arrival" is computed by comparing the arrival times of
paths assuming all signals are late-arriving. Similarly,
"Skew for the Earliest Arrival" is computed by comparing
the arrival times of paths assuming all signals are
early-arriving.
Use the -stdout option to direct the report to the Tcl
console (default), the -file option to write the
report to a file or the -panel_name option to direct
the report to the TimeQuest graphical user
interface. You can use these options in any
combination.
Use the -include and -exclude options to include or
exclude one or more of the following: register micro
parameters (utsu, uth, utco), clock arrival times
(from_clock, to_clock), clock uncertainty
(clock_uncertainty), common clock path pessimism
removal (ccpp), input and output delays (input_delay,
output_delay) and on-die variation (odv). By default,
max skew analysis includes data arrival times, clock
arrival times, register micro parameters, clock
uncertainty, on-die variation and ccpp removal. Among
these, only ccpp removal is disabled during the Fitter
by default. When -include is used, those in the
inclusion list are added to the default
analysis. Similarly, when -exclude is used, those in
the exclusion list are excluded from the default
analysis. When both the -include and -exclude options
specify the same parameter, that parameter is
excluded.
When TimeQuest Spectra-Q is enabled, -exclude and -include are
not supported. All components will be included.
Use the -npaths option to limit the number of path
result pairs reported for each set_max_skew
constraint. If you do not specify this option,
report_skew only reports the result pair for the
single worst-case path. Use the -less_than_slack
option to limit output to all paths with skew greater
than the specified value, up to the number specified
with -npaths.
Use the -detail option to specify the desired level of
report detail. The "-detail summary" option generates a
single table listing only the highlights of each path
(and is the same as -summary option, which this
replaces. "-detail path_only" (default) reports the
path from the source to the destination without any
detail about the clock path. Instead, the clock
network delay is shown as a single number. "-detail
path_and_clock" extends the arrival and required paths
back to the launch and latch clocks. "-detail
full_path" continues tracing back through generated
clocks to the underlying base clock.
The -show_routing option displays detailed routing
information in the path. Lines marked "IC" without the
option are shown, but only as a placeholder. The
routing elements for that line are broken out
individually and listed before the line.
The return value of this command is a two-element
list. The first number is the number of paths found in
the analysis. The second is the worst-case skew, in
terms of the current default time unit.
The "RF" column in the report output uses a two-letter
symbol to indicate the rise/fall transition that
occurs at that point in the path.
Possible "RF" values are:
Value Description
------- -------------------------------
(empty) Unknown transition
R Rising output
F Falling output
RR Rising input, rising output
RF Rising input, falling output
FR Falling input, rising output
FF Falling input, falling output
The "Type" column in the report uses a symbol to
indicate what type of delay occurs at that point in
the path.
Possible "Type" values are:
Value Description
------- -------------------------------
CELL Cell delay
COMP PLL clock network compensation delay
IC Interconnect delay
iExt External input delay
LOOP Lumped combinational loop delay
oExt External output delay
RE Routing element (only for paths
generated with the -show_routing option)
uTco Register micro-Tco time
uTsu Register micro-Tsu time
uTh Register micro-Th time
|
Example Usage |
project_open my_project
create_timing_netlist
read_sdc
update_timing_netlist
# show worst 10 paths for each earliest and latest arrival results
report_skew -from [get_ports input[*]] -to [get_registers *] -panel_name "Report Skew" -npaths 10 -greater_than_skew 0.100 -detail full_path
delete_timing_netlist
project_close
|
Return Value |
Code Name |
Code |
String Return |
|
TCL_OK |
0 |
INFO: Operation successful |
|
TCL_ERROR |
1 |
ERROR: Options -include and -exclude are not supported in TimeQuest Spectra-Q. |
|
TCL_ERROR |
1 |
ERROR: Timing netlist does not exist. Use create_timing_netlist to create a timing netlist. |
|
TCL_ERROR |
1 |
ERROR: Report database is not open |