Specifies frequencies, duty cycles, and uncertainties.
If you are a Digital Design or STA (Static Timing Analysis) engineer, two things keep you up at night: and timing closure .
# Set the driving cell for an input port to mimic real circuit behavior set_driving_cell -lib_cell BUFX2 -pin Y [get_ports data_in] # Set the capacitive load on an output port set_load 0.05 [get_ports data_out] Use code with caution. 4. Managing Complex Clock Relationships synopsys timing constraints and optimization user guide 2021
: Defining clocks derived from internal logic (e.g., dividers, PLLs) using create_generated_clock Clock Characteristics
Modeling jitter and skew. 5. Static Timing Analysis (STA) with PrimeTime Specifies frequencies, duty cycles, and uncertainties
: Defining the maximum allowable rise/fall time for signals. 6. Optimization Techniques Optimization Phases
Synopsys tools rely on the industry-standard format to understand the performance goals of your circuit. Without proper constraints, synthesis and implementation tools cannot optimize the logic effectively, leading to either unroutable congestion or missed performance targets. The Role of Static Timing Analysis (STA) Static Timing Analysis (STA) with PrimeTime : Defining
Defining clock relationships and Clock Domain Crossing (CDC) constraints to manage asynchronous interfaces.
Mastering Synopsys timing constraints and optimization is a continuous process. By 2021, the emphasis was on a unified, physically-aware optimization flow (Fusion Compiler) and rigorous, multi-corner sign-off (PrimeTime). Properly creating SDC constraints and utilizing the advanced optimization capabilities of the Synopsys toolchain ensures that designs meet the high-performance demands of the modern digital landscape.
This command defines the setup and hold requirements of the external device receiving signals from your chip's output ports.
Synopsys Timing Constraints and Optimization User Guide 2021: Achieving Optimal PPA