Inferred Tristate buffers are implemented with different device primitives when driving the following:
• An external pin of the circuit ( OBUFT )
• An Internal bus ( BUFT ):
° An inferred BUFT is converted automatically to logic realized in LUTs by Vivado synthesis.
° When an internal bus inferring a BUFT is driving an output of the top module, the Vivado synthesis infers an OBUF .