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AR# 55833

How to connect unused GT I/Os


Why does the documentation suggest to leave the unused GT I/O ports connected to GND, but Xilinx development boards have all available GT I/Os floating?


The user guide provides all details about how to connect unused GT I/Os. A floating I/O is needed on development boards because any GT I/O must be accessible for tests and measurements. If a particular GT is not used, this seems to be in contrast with UG recommendation.

The user guide also suggests to ground unused GT I/Os because this is a "good design" practice. Of course, an I/O that is floating or (that is a similar condition) connected to decoupling capacitor will not break just because it is floating.
AR# 55833
Date 05/02/2013
Status Active
Type General Article
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