SPRUI30H November 2015 – May 2024 DRA745 , DRA746 , DRA750 , DRA756
The controller has two main clock domains: the L3_MAIN bridge (ports) and the PCIe core.
The L3_MAIN bridge runs on a single clock. That same clock is used to run both the PCIe controller master and slave ports. It can be divided, with independently ratios for master and slave. However, both sides are typically expected to run at the same speed, as both are capable of the same performance.
There is an auxiliary clock - LP_CLK which is a PCIe_SS internal low-power clock, used when pipe clock is stopped. It is assumed to be always available when the module is not idle.
The PCIe core runs on the PIPE clock whenever that clock is provided by the relevant PCIe_PHY. When the PCIe link is in a low-power state and the PIPE clock is not available, the core splits in two sub-domains: