The user guide frequently addresses "Classic Scenarios" faced by designers during synthesis and implementation, offering proven solutions to common roadblocks.
Automated insertion of gating cells to reduce dynamic power. Multi-Vt Optimization: Using high-threshold voltage ( Vtcap V sub t
| | Example SDC Command | Description | | :--- | :--- | :--- | | Basic Clock | create_clock -period 5.0 [get_ports CLK] | Creates a clock on port CLK with a period of 5.0 ns and default 50% duty cycle. | | Generated Clock | create_generated_clock -source [get_ports CLK] -divide_by 2 [get_pins U1/Q] | Creates a clock at pin U1/Q that is half the frequency of the master clock at CLK . | | Virtual Clock | create_clock -period 10.0 -name VIRT_CLK | Defines an ideal clock VIRT_CLK to be used for I/O constraints. |
Here are some common commands used to define timing constraints: synopsys timing constraints and optimization user guide 2021
Detail the difference between set up and hold time optimization. Give tips for resolving high-fanout net issues. Let me know which topic you'd like to dive into! Synopsys Timing Constraints And Optimization User Guide
The "Synopsys Timing Constraints and Optimization User Guide" is primarily distributed to licensed customers through the support portal. The guide is also shared across online engineering communities as a valuable resource.
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] Give tips for resolving high-fanout net issues
The guide provides best practices for leveraging multicore processing. It details the set_host_options command and explains how the optimization engine partitions the design graph for parallel processing. The 2021 updates highlight improvements in the "incremental compile" flow, allowing engineers to make
: Configuration registers written once during boot-up and left unchanged during operational mode.
Generated clocks are derived from primary clocks via internal design logic like clock dividers, phase-locked loops (PLLs), or multiplexers. They must be explicitly declared so the timing engine can maintain phase relationships. For complex SoCs
While slight over-constraining can help achieve closure, extreme over-constraint can lead to excessive runtime and poor area/power results. 4. Advanced Optimization Techniques
Note: For the latest specific commands and methodology, always consult the documentation within your Synopsys SolvNetPlus account associated with your tool version.
For complex SoCs, Synopsys highlights the Timing Constraints Manager (TCM) , which automates the verification and promotion of constraints from IP to SoC levels.
While the core SDC syntax remains consistent, the 2021 user guide places increased emphasis on: