Intel® Quartus® Prime Standard Edition User Guide: Design Constraints

ID 683492
Date 4/18/2022
Public
Document Table of Contents

1.2.4. Synopsys* Design Constraint (.sdc) Files

Intel® Quartus® Prime software keeps timing constraints in .sdc files, which use Tcl syntax. You can embed these constraints in a scripted compilation flow, and even create sets of .sdc files for timing optimization.

.sdc File

The example shows the timing constrains of a small design.

## PROGRAM "Quartus Prime"
## VERSION "Version 17.0.0 Build 595 04/25/2017 SJ Standard Edition"		
## DATE    "Wed May 10 14:03:25 2017"  		
##
## DEVICE  "EP4CGX15BF14C6"
##
#**************************************************************
# Time Information
#**************************************************************
set_time_format -unit ns -decimal_places 3  		
#**************************************************************
# Create Clock
#************************************************************** 		
create_clock -name {clk} -period 4.000 -waveform { 0.000 2.000 } [get_ports {clk}]
create_clock -name {clkx2} -period 4.000 -waveform { 0.000 2.000 } [get_ports {clkx2}]
#**************************************************************
# Set Clock Uncertainty
#**************************************************************
set_clock_uncertainty -rise_from [get_clocks {clkx2}] -rise_to [get_clocks {clkx2}]  0.020  
set_clock_uncertainty -rise_from [get_clocks {clkx2}] -fall_to [get_clocks {clkx2}]  0.020  
set_clock_uncertainty -fall_from [get_clocks {clkx2}] -rise_to [get_clocks {clkx2}]  0.020  
set_clock_uncertainty -fall_from [get_clocks {clkx2}] -fall_to [get_clocks {clkx2}]  0.020  
set_clock_uncertainty -rise_from [get_clocks {clk}] -rise_to [get_clocks {clkx2}]  0.040  
set_clock_uncertainty -rise_from [get_clocks {clk}] -fall_to [get_clocks {clkx2}]  0.040  
set_clock_uncertainty -rise_from [get_clocks {clk}] -rise_to [get_clocks {clk}]  0.020  
set_clock_uncertainty -rise_from [get_clocks {clk}] -fall_to [get_clocks {clk}]  0.020  
set_clock_uncertainty -fall_from [get_clocks {clk}] -rise_to [get_clocks {clkx2}]  0.040  
set_clock_uncertainty -fall_from [get_clocks {clk}] -fall_to [get_clocks {clkx2}]  0.040  
set_clock_uncertainty -fall_from [get_clocks {clk}] -rise_to [get_clocks {clk}]  0.020  
set_clock_uncertainty -fall_from [get_clocks {clk}] -fall_to [get_clocks {clk}]  0.020  
#**************************************************************
# Set False Path
#************************************************************** 		
set_false_path -from [get_clocks {clk clkx2}] -through [get_pins -compatibility_mode *]  -to [get_clocks {clk clkx2}]

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