SNLA415 August   2022 DS160PT801

 

  1.   Abstract
  2.   Trademarks
  3. 1Introduction
  4. 2History
  5. 3Components of PCIe Communication
    1. 3.1 Root Complex
    2. 3.2 Repeater
    3. 3.3 Endpoints
  6. 4Signaling
    1. 4.1 PERST
    2. 4.2 WAKE and CLKREQ
    3. 4.3 REFCLK
  7. 5Link Training
    1. 5.1 Receiver Detect (Rx Detect)
    2. 5.2 Polling
    3. 5.3 Configuration
  8. 6Link Equalization
    1. 6.1 Phase 0 and 1
    2. 6.2 Phase 2 and 3
  9. 7Summary
  10. 8References

4 Signaling

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 4-1 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.

GUID-20220804-SS0I-T7RZ-SQM9-KZFCNZXCKJBX-low.png Figure 4-1 PCIe Control Signals