Clock Usage for Registered Interface - 1.0 English - PG375

There are a variety of clocks that can be used to clock the register, if enabled. These rules are applied in order:

1. If clock domain crossing is enabled and an interface-specific AXI clock is not needed, then the clock created for the clock domain crossing sychronizer (<interface name>_ref_clk) is used to clock the register.
2. If an interface-specific AXI clock is needed (<interface name>_aclk), then that is used to clock the register.
3. If the core has an AXI clock already (aclk) because it has AXI control or status interfaces, then aclk is used to clock the register.
4. Otherwise, decouple_ref_clock is enabled and is used to clock the register.