And Optimization User Guide 2021 - Synopsys Timing Constraints

"When creating a generated clock using create_generated_clock, always specify the -source object as the master clock pin. In 2021, the -divide_by or -multiply_by options are recommended over -edges for simple frequency division to improve propagation accuracy. For non-integer division, use -edge_shift with care, as it may introduce glitches if the source clock edge alignment is not validated."

Don't read it front to back. Do this instead:

If you want, I can:

Synopsys Timing Constraints and Optimization User Guide (specifically versions around ) is a critical resource for designers using tools like Design Compiler Fusion Compiler

provides the methodology for defining timing requirements and using optimization engines to meet Performance, Power, and Area (PPA) goals Key Features and Updates (2021 Era) SDC 2.1 Support : The 2021 documentation aligns with Synopsys Design Constraints (SDC) version 2.1 , which introduced changes such as replacing the set_clock_sense command with set_sense -type clock for better clarity in constraint scripts. Fusion Technology Integration : The guide emphasizes Synopsys Fusion Technology

, which enables a unified timing analysis engine across synthesis, placement, and routing to ensure timing signoff correlation and reduce iterations. Advanced Timing Analysis All-Aware Analysis

: Support for thermal-aware, aging-aware, and IR-aware timing to account for nanometer-scale physical effects. Multi-Input Switching (MIS)

: Enhanced modeling for more accurate delay calculation in complex logic gates. Constraint Management & Verification Timing Constraints Manager

: Incorporates technology for "low-noise" constraint verification, automatically flagging real issues (like incorrect timing exceptions) while filtering out irrelevant warnings. Automated Promotion/Demotion

: Tools to manage constraints as they move from RTL to gate-level and from IP blocks to the full SoC. Optimization Strategies Adaptive Retiming : Techniques using commands like compile_ultra -retime synopsys timing constraints and optimization user guide 2021

to move registers across combinational logic for better performance without changing functional behavior. Machine Learning Integration

: Inclusion of ML-based power recovery and Path-Based Analysis (PBA) to squeeze extra performance and power savings from the design. Multibit Optimization

: Automatic mapping of single-bit registers to multibit components to save area and reduce power. picture.iczhiku.com Core Functional Areas Design Compiler Optimization Reference Manual

* 1. Basic Concepts for Optimizing Designs. Using DC Ultra . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . picture.iczhiku.com

Defining Timing Constraints in Four Steps - 2025.2 English - UG1387

Introduction

Synopsys Timing Constraints and Optimization User Guide 2021 is a comprehensive guide that provides detailed information on how to use Synopsys tools to constrain and optimize digital designs for timing performance. The guide covers the basics of timing constraints, optimization techniques, and best practices for achieving optimal timing results.

Understanding Timing Constraints

Timing constraints are used to specify the timing requirements of a digital design. They define the relationships between signals and the timing relationships between different parts of the design. There are several types of timing constraints, including: Don't read it front to back

Defining Timing Constraints

To define timing constraints, you need to use a constraints file, which is a text file that contains a set of commands that specify the timing requirements of the design. The constraints file is used by Synopsys tools to analyze and optimize the design.

Here are some common commands used to define timing constraints:

Optimization Techniques

Synopsys tools provide several optimization techniques to improve the timing performance of a design. These techniques include:

Using Synopsys Tools for Timing Optimization

Synopsys provides a range of tools for timing optimization, including:

Best Practices for Timing Optimization

Here are some best practices for timing optimization: If you want, I can:

Example Use Case

Here is an example use case for timing optimization:

  • Optimization goal: Achieve a maximum delay of 10 ns between the input and output ports.

    • Step-by-Step Solution

    Here is a step-by-step solution to the example use case:

    create_clock -name clk -period 10 -waveform 0 5
set_input_delay -max 3 -clock clk [get_ports input_port]
set_output_delay -max 2 -clock clk [get_ports output_port]

    dc_shell -f design.tcl -o design.sv

    pt_shell -f design.tcl -o design.rpt

    Conclusion

    In conclusion, Synopsys Timing Constraints and Optimization User Guide 2021 provides a comprehensive guide to constraining and optimizing digital designs for timing performance. By following the guidelines and best practices outlined in this guide, designers can achieve optimal timing results and ensure that their designs meet the required specifications.

    References

    Appendix

    Here is an appendix of useful commands and syntax:

    The guide introduces a "Board-Aware" constraint flow.

    The guide concludes with a "Best Practices" section, highlighting common errors: