SPRADH9 June 2024 AM6442
Each component of PCIe communication (except for redrivers) have the following control signals: PERST, WAKE, CLKREQ, and REFCLK. These signals work to generate high-speed signals and communicate with other PCIe devices. Figure 2-2 shows the diagram of PCIe devices with the control signals. This diagram shows that all of the control signals except REFCLK are active low signals.
In Figure 2-2, the repeater is referred as retimer