Synopsys Timing Constraints And Optimization User Guide 2021 ((better))

This guide is deeply integrated with the format—an industry-standard, TCL-based language used to communicate design intent regarding timing, power, and area across Synopsys tools like Design Compiler, IC Compiler, and PrimeTime.

: Understanding static timing analysis (STA), setup and hold time, and the role of constraints in the synthesis flow. The SDC Format

# Disable timing analysis on a test mode signal set_false_path -from [get_ports test_mode] Use code with caution. Multicycle Paths

# Define a main system clock with a 10ns period and 50% duty cycle create_clock -name SYS_CLK -period 10.0 [get_ports sys_clk] Use code with caution. Generated Clocks synopsys timing constraints and optimization user guide 2021

-waveform 0.0 1.0 : Defines a 50% duty cycle (rises at 0.0, falls at 1.0). create_generated_clock

report_timing -delay_type min : Generates hold (min delay) reports.

Data must travel from point A to point B before the clock ticks again. This guide is deeply integrated with the format—an

# Allow 3 clock cycles for data to propagate through a complex multiplier unit set_multicycle_path 3 -setup -from [get_pins mult_core/start_reg/CP] -to [get_pins mult_core/end_reg/D] # Adjust the hold check accordingly to point to the launch cycle set_multicycle_path 2 -hold -from [get_pins mult_core/start_reg/CP] -to [get_pins mult_core/end_reg/D] Use code with caution. 6. Synthesis and Optimization Strategies

Note: The engine will actively sacrifice area and power to fix a Max Transition or a Setup timing violation. Key Optimization Commands High-Effort Optimization

: Completing port constraints with drive strength and load information. 4. Timing Exceptions False Paths Multicycle Paths # Define a main system clock

Here is why you should re-read (or read) this guide, and the three key takeaways that will improve your PPA (Power, Performance, Area).

The 2021 release of the user guide sits at a sweet spot. It bridges the gap between the traditional PrimeTime/ICC2 flows and the modern complexities of multi-corner, multi-mode (MCMM) design.

For the physical synthesis flow (IC Compiler), the guide discusses:

addresses advanced topics that are critical for high-performance design. It explains concepts like time borrowing , where a latch can borrow time from the next clock phase to resolve a timing violation, and introduces techniques like normalized slack analysis . This metric helps identify paths that have the greatest impact on overall clock frequency, even if their absolute slack is not the worst in the design.

To establish a clock domain at an input port of the design, the create_clock command is utilized. This defines the period, waveform shape, and name of the clock.