The IBUFDS_IBUFDISABLE (HP and HD I/O banks only) primitive shown in the following figure is a differential input buffer with a disable port that can be used as an additional power saving feature for periods when the input is not used. The IBUFDS_IBUFDISABLE primitive can disable the input buffer and force the O output to the internal logic to a logic Low when the IBUFDISABLE signal is asserted High.
The IBUFDS_IBUFDISABLE_XP5 (XP5IO I/O banks only) can be used as an additional power saving feature for periods when the input is not used in an XP5IO I/O bank. The IBUFDS_IBUFDISABLE_XP5 primitive can disable the input buffer and force the O output to the internal logic to a logic High when the IBUFDISABLE signal is asserted High. The USE_IBUFDISABLE attribute must be set to TRUE, the IBUFDISABLE port must be controlled and SIM_DEVICE set to ULTRASCALE_PLUS for this primitive to have the expected behavior that is specific to the Spartan UltraScale+ devices. This feature can be used to reduce power whenever the I/O is idle.