X4 Slot; Express Card Example; Figure 5 Pcie X4 Reference Schematic - Emerson COM Express Carrier Design Manual

 WAKE0# is asserted by the slot card to cause COM Express module wake-up at module pin B66. This
is an open-drain signal. It is an input to the module and is pulled up on the module. Other WAKE0#
sources may pull this line low; it is a shared line.
Slot JTAG pins on A5-A8 are not used.

3.4.4 x4 Slot

Figure 5 PCIe x4 Reference Schematic

The difference between x1 and x4 PCIe slots is the addition of three PCIE lanes and a PRSNT2 signal in
the x4 slot.

3.4.5 Express Card Example

ExpressCards are small form factor hot-swappable peripheral cards designed primarily for mobile
computing. The card's electrical interface is through either an x1 PCIe link or a USB 2.0 link. Per the
ExpressCard Source Specification, the host interface should support both the PCIe and USB links. The
ExpressCard device may utilize one or the other, or both interfaces.
There are several form factors defined: 34 mm x 75 mm; 54 mm x 75 mm; 34mm x 100mm, and
54 mm x 100 mm. All of the form factors use the same electrical and physical socket interface.
ExpressCards are the successor to Card Bus cards (which are PCI-based). Card Bus cards, in turn, are the
successors to PCMCIA cards. All three formats are defined by the PCMCIA Consortium.
The source specification document for ExpressCards is the ExpressCard Standard.
Page 24 of 103 COM Express Carrier Type 2
Design Guide