Use of LINKCAP
The backplane signal LINKCAP indicates the link configuration of the used PXIe chassis. The PXIeCOMe is only capable of using a PXIe chassis with a 4-link configuration, and so LINKCAP should always be ‘1’. The current solution to be able to read the value of LINKCAP through IC33 and CEX_GPI1 is debatable.
A better solution would be to also use LINKCAP in the circuit to control PE_PS_ON_N (see PXIeCOMe schematic page Power Management On/Off/Standby and SMBus).