3.2.1 Using PERSTn When PCIe is Configured as a Root Port

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PERSTn is a fundamental reset signal defined in both PCI Express Base Specification and PCI Express Card Electromechanical Specification. Root port issues this reset signal through PCIe slots to reset the entire PCIe fabric hierarchy. The APB Master can assert PCIe PERSTn signal through PCIe APB register space. When the host is power cycled, the PERSTn signal is asserted by the PCIe_INIT_MONITOR until the PCIe controller in the Root port is initialized.

The following figure shows the PCIe configurator when PCIe is configured as a PCIe Root port.

Figure 3-10. PCIe Configurator When PCIe is Configured as a PCIe Root Port

The following figure shows the example of PCIe interface with the PERSTn signal.

Figure 3-11. Complete PCIe Interface Example with PERSTn Signal