Intel® Quartus® Prime Pro Edition User Guide: Scripting

ID 683432
Date 10/04/2021
Public

A newer version of this document is available. Customers should click here to go to the newest version.

Document Table of Contents

3.1.29.2. check_timing (::quartus::sta)

The following table displays information for the check_timing Tcl command:

Tcl Package and Version

Belongs to ::quartus::sta

Syntax check_timing [-h | -help] [-long_help] [-append] [-file <name> ] [-include <check_list> ] [-panel_name <name> ] [-stdout]
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.
-file <name> Sends the results to an ASCII or HTML file. Depending on the extension
-include <check_list> Checks to perform
-panel_name <name> Sends the results to the panel and specifies the name of the new panel
-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.
Description

Checks for problems in the design or problems with design constraints. The check_timing command performs a series of different checks based on user-specified variables and options. There is no default list of checks. Use the -include option to specify which checks to perform. You must preceed check_timing with update_timing_netlist. The no_clock check reports whether registers have at least one clock at their clock pin, and that ports determined to be clocks have a clock assigned to them, and also checks that PLLs have a clock assignment. The multiple_clock check verifies that registers have at most one clock at their clock pin. (When multiple clocks reach a register clock pin, it is undefined which clock is used for analysis. The generated_clock check verifies that generated clocks are valid. Generated clocks must have a source that is triggered by a valid clock. The no_input_delay check verifies that every input port that is not determined to be a clock has an input delay assignment. The no_output_delay check verifies that every output port has an output delay constraint. The partial_input_delay check verifies that input delays are complete, and ensures that input delays have a rise-min, fall-min, rise-max, and fall-max portion set. The partial_output_delay check verifies that output delays are complete, and makes sure that output delays have a rise-min, fall-min, rise-max, and fall-max portion set. The io_min_max_delay_consistency check verifies that min delay values specified by set_input_delay or set_output_delay assignments are less than max delay values. The reference_pin check verifies that reference pins specified in set_input_delay and set_output_delay using the -reference_pin option are valid. A reference_pin is valid if the -clock option specified in the same set_input_delay/set_output_delay command matches the clock that is in the direct fanin of the reference_pin. Being in the direct fanin of the reference_pin means that there must be no keepers between the clock and the reference_pin. The latency_override check reports whether the clock latency set on a port or pin overrides the more generic clock latency set on a clock. Clock latency can be set on a clock, where the latency applies to all keepers clocked by the clock, whereas clock latency can also be set on a port or pin, where the latency applies to registers in the fanout of the port or pin. The loops check verifies that there are no strongly connected components in the netlist. These loops prevent a design from being properly analyzed. The loops check also reports if loops exist but were marked so that they would not be traversed. The latches check reports latches in the design and warns that latches may not be analyzed properly. For best results, change your design to remove latches whenever possible. The pos_neg_clock_domain check determines if any register is clocked by both the rising and falling edges of the same clock. If this scenario is necessary such as in a clock multiplexer, create two separate clocks that have similar settings and are assigned to the same node. The pll_cross_check checks the clocks that are assigned to a PLL against the PLL settings defined in design files. Inconsistent settings or an unmatched number of clocks associated with the PLL are reported to the user. The uncertainty check reports each clock-to-clock transfer that does not have a clock uncertainty assignment set between the two clocks. When a device family has derive_clock_uncertainty support, this report also checks if a user-defined set_clock_uncertainty assignment has a less than recommended clock uncertainty value. The virtual_clock check reports all unreferenced virtual clocks. It also reports if design does not have any virtual clock assignment. The partial_multicycle check ensures that each setup multicycle assignment has a corresponding hold multicycle assignment, and each hold muticycle assignment has a corresponding setup multicycle assignment. The multicycle_consistency check reports all the multicycle cases where a setup multicycle does not equal one greater than the hold multicycle. Hold multicycle assignments are usually one cycle less than setup multicycle assignments. The partial_min_max_delay check verifies that each minimum delay assignment has a corresponding maximum delay assignment, and vice versa. The clock_assignments_on_output_ports check reports all the clock assignments that have been applied to output ports. The input_delay_assigned_to_clock check verifies that no input delay value is set for a clock. Input delays set on clock ports are ignored because clock-as-data analysis takes precedence. The internal_io_delay check reports all the IO delays that have no specifications for -reference_pin and -source_latency_included, and -clock is a clock that is not assigned to a top level input or output port.

Example Usage
# Constrain design
create_clock -name clk -period 4.000 -waveform { 0.000 2.000 } [get_ports clk]
set_input_delay -clock clk2 1.5 [get_ports in*]
set_output_delay -clock clk 1.6 [get_ports out*]
set_false_path -from [get_keepers in] -through [get_nets r1] -to [get_keepers out]

# Check if there were any problems
check_timing -include {loops latches no_input_delay partial_input_delay}
Return Value Code Name Code String Return
TCL_OK 0 INFO: Operation successful

Did you find the information on this page useful?

Characters remaining:

Feedback Message