Synopsys Timing Constraints And Optimization User Guide 2021 ✯
The 2021 guide emphasizes a methodical approach to defining the design environment. The constraints are categorized as follows:
A key point of emphasis in the user guide is . Choosing the wrong method for specifying an exception can lead to long runtimes. For example, when dealing with false paths between two clock domains, applying the exception at the clock level ( -from [get_clocks CLK1] -to [get_clocks CLK2] ) is far more efficient than listing hundreds of individual register-to-register paths.
The primary goal of providing accurate constraints is to enable the tools to optimize the design. The user guide details how synthesis and physical design engines use constraints to drive their optimization algorithms. synopsys timing constraints and optimization user guide 2021
At the heart of the guide lies the principle of . Unlike dynamic simulation, which tests functionality using specific input vectors, STA is a much faster and more thorough method that mathematically verifies the timing performance of a design. It breaks the design into all possible timing paths, calculates the signal propagation delay along each path, and checks for violations of timing constraints.
The guide details techniques for achieving while balancing area and power: Timing Constraints Manager | Synopsys The 2021 guide emphasizes a methodical approach to
# Declare two clock domains as completely asynchronous set_clock_groups -asynchronous -group SYS_CLK -group TX_CLK RX_CLK Use code with caution. 5. Non-Standard Timing Paths: Exceptions
Max Input Delay=Tclk_to_q_ext+Tpcb_trace_maxMax Input Delay equals cap T sub clk_to_q_ext end-sub plus cap T sub pcb_trace_max end-sub For example, when dealing with false paths between
Specifying input and output delays relative to system clocks.
: Creating real, virtual, and generated clocks to establish the timing baseline.
By default, synthesis tools assume all paths must close timing within a single clock cycle. When this assumption is false, timing exceptions must be declared to avoid wasting optimization effort on false paths. False Paths