Input buffers, 3-state outputs, and bidirectional buffers can have a weak pull-up resistor, a weak pull-down resistor, or a weak keeper circuit. PULLTYPE attribute has the following possible values.
• NONE
• PULLUP
• PULLDOWN
• KEEPER
This feature can be invoked by adding the following possible constraint values to the relevant net of the buffers. These attributes use the following syntaxes in the XDC file:
set_property PULLTYPE value [get_ports port_name]
For more information on implementing these attributes on either individual I/Os or globally for all I/Os, see the pull-up, pull-down, and keeper descriptions in the Vivado Design Suite Properties Reference Guide (UG912) [Ref 6] .