Advantech AIMB-233 User Manual page 59

 M.2 [Enabled]
Enable or disable PCI Express Root Port controller.
ASPM Support [Auto]

L1 Substates [L1.1 & L1.2]

 PCIe Speed [Auto]
3.2.3.7 PCIe configration
PCIEx1 [Enabled]

Enable or disable PCI Express Root Port controller.
 ASPM Support [Auto]
 L1 Substates [L1.1 & L1.2]
 PCIe Speed [Auto]
47 AIMB-233 User Manual