Can I connect unused GXB_RX pins to GND in Arria V and Cyclone V devices?

Description

Yes, you can connect unused GXB_RX pins in Arria® V and Cyclone® V devices directly to GND. 

The Cyclone V Device Family Pin Connection Guidelines (PDF) version 1.0 and Arria V Device Family Pin Connection Guidelines (PDF) version 1.1 state unused GXB_RX pins should be tied to GND through a 10-k. resistor.  This guideline can still be followed, however, for a more simple board layout, you can tie unused GXB_RX pins directly to GND without the use of a pull down resistor.

Resolution

Future versions of the Arria V and Cyclone V Pin Connection Guidelines will be updated to state the unused GXB_RX pins can be tied directly to GND.