Synopsys Timing Constraints And Optimization User Guide 2021 _verified_ Online

Explain how to set up create_clock or set_input_delay for a specific interface.

# Prioritize timing over area considerations during compile set_max_area 0 # Fix hold time violations automatically during synthesis (compile_ultra) set_fix_hold [all_clocks] # Enable high-effort optimization for aggressive timing closure compile_ultra -retime -gate_clock Use code with caution.

: set_clock_uncertainty adds margin for jitter and skew, while set_clock_latency models insertion delay.

Input delay defines the time elapsed before data reaches the input port of your design, measured relative to an external clock edge. synopsys timing constraints and optimization user guide 2021

Ensures that the data remains stable long enough after the capturing clock edge to prevent race conditions. It is independent of clock frequency. 2. Establishing the Clock Network

: Start with "loose" constraints to explore the design space, then tighten them as the physical floorplan matures.

Modern System-on-Chips (SoCs) employ dozens of clock domains. By default, Synopsys tools assume all clocks are synchronous and will attempt to analyze paths between them. You must explicitly override this behavior for asynchronous domains. Asynchronous and Logically Exclusive Clocks Explain how to set up create_clock or set_input_delay

: Constraining the external environment for the chip's ports.

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

: Used for setup analysis. It tells the tool that the external device takes up to 0.6 ns to drive the data, leaving less time for internal logic. -min : Used for hold analysis. Output Delay Input delay defines the time elapsed before data

Mastering requires a balance between strict constraints and intelligent design methodologies. By utilizing the 2021-2022 recommended approaches—robust SDC writing, smart environmental settings, and leveraging Synopsys' power-aware optimization—designers can achieve superior performance and power efficiency.

Choosing the best drive strength for timing vs. power.