Advantech SOM-Express Design Guide
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Chapter 5 Carrier Board Design Guidelines
5.10.2.3 Terminating
Unused PCI Express Ports
If a PCI Express port will not be implement on the platform, the PCIE _TX+/-[x] and
/-[x] signals may be left as No Connects.
Note:
Where “x” is the port number left as No Connect.
If no PCI Express ports will be implemented on the platform, the PCIE _TX+/- [0:5]
and PCIE _RX+/- [0:5] signals may be left as No Connect and the WAKE# signal
should be pulled-up to VccSus 3_3 with a 680
Ω
– 1 k
Ω
resistor. Figure 5-46 shows
the circuit.
SOM-Express
TX [0]+
TX [0] -
RX [0]+
RX [0] -
.
.
.
.
RX [5] -
WAKE#
VccSus 3_3
Figure 5-46 Example of terminating unused PCI Express ports
